Radiology Exam 1

panosteitis in

Large breed dogs German shepherd - common Basset hounds others Young - 5-12 months Common thru 2 years Rare 2 to 7 years Can be recurrent Non-inflammatory Self-limiting

Additional imaging

Repeat rads of area in 710 14 days -Rate of lesion character change -Aggressive lesions commonly show aggressive progression over time Comparative or Skeletal survey radiographs Thoracic imaging for evidence suggesting - metastasis or changes more suggestive of other systemic disease (eg.) mycoses hypertrophic osteopathy CT / MRI / Scintigraphy to further characterize lesion, particularly the extent

T or F: The radiographs show well-defined borders to the palpated mass that separate it from the thigh muscle.

True

Which of the following is the radiographic diagnosis for this patient?

a. Aggressive bone lesion with pathologic fracture. d. Osteosarcoma - this is an etiologic diagnosis. A good etiologic differential, however it coould be another tumor type. Most osteosarcomas begin in the metaphyseal region of the bone, so this one is not adhering to that common distribution. A biopsy would be needed RIGHT HUMERUS: Mediolateral and craniocaudal projections were obtained. There is a region of osteolysis within the proximal portion of the humeral diaphysis. The cortices are thinned and there is marked geographic to permeative lysis. Proximal and distal zones of transition are not discrete, however a portion of the distal zone is better defined. Best appreciated in the craniocaudal projection, is an obliquely oriented radiolucent line (fracture) extending from proximomedial to distolateral through the lytic region with the distal portion of the humerus mildly displaced medial, caudal and proximal at the level of the fracture. The surrounding soft tissues are mildly circumferentially thickened and cranially convex over the fracture site. No other regional abnormalities. Conclusions: 1. Marked (aggressive)proximal humeral lysis with complete short oblique pathologic fracture is most consistent with a malignant neoplasia (metastatic infiltrate associated with an unknown primary, a primary hemangiosarcoma, or round cell tumor; osteosarcoma is considered less likely due to the diaphyseal location) however fungal osteomyelitis is also a differential. Fungal antigen testing could be considered to rule out fungal disease as well as discussing history of travel. Biopsy will likely be needed for definitive diagnosis. This lesion is aggressive with a pathologic fracture. Relative to the zones of transition in the cranial-caudal view it seems to be very discrete distally but this is not well correlated in the medial-lateral view. So this is reminding us of a couple of things - 1) we need to put the 2 orthogonal views together to get a better "picture" of the overall changes; 2) the most important/significant features of the lesion in this dog is the change in the cortical thickness. There is thinning of the cortex in areas other than the plane of the fracture. In this case, the fracture is probably what has caused the acute lameness that prompted the presentation to you the Veterinarian. But the quality of the bone - that it is not normal - indicates that pre-existing or underlying bone disease has allowed the bone to fail and thus fracture. With every fracture it is important to assess the quality of the bone. Normal bone requires a fairly strong force to cause it to break; diseased bone can fail and fracture under minimal stresses/forces. This lesion gives rise to a list of etiologic differentials because of the signalment. Without considering the patient signalment primary bone tumor is probably at the top of the list because it is an aggressive lesion and the 2 most common aggressive lesions are neoplasia and infection. Osteosarcoma is the most common of the primary bone tumors; and the humerus is a common location BUT that common location is the proximal humeral metaphysis and this dog's lesion is centered in the proximal diaphysis so that would make this not a "classical" example. When you factor in the breed - that supports osteosarcoma; but age - 3 yrs - is not as common as older around 7 - but there is a bimodal age relative to the documented cases of osteosarcoma with peaks and 2-3 and 7. The younger age peak is significantly less common that the older peak. Many other tumor types could occur here including metastatic - however the dog is young for other body organ tumors. So infection - most likely mycotic agent - still remains a reasonable differential for this dog and has to be considered in the "what to do next" phase of case management.

Fracture

discontinuity in the cortical bone

Lysis =

dissolution or destruction of cells

horse locations of OCD

**Intermediate ridge distal tibia * Lateral trochlea talus# (# Also commonly seen as a subchondral depression without fragmentation) *Lateral femoral trochlea Medial trochlea talus# Medial femoral trochlea Dorsal sagittal ridge MC/MT 3

Border effacement effects

-Loss of expected border because of loss of contrast Two substances or structures of the same radiographic opacity when in contact cause the contacting borders to become "invisible". • Feline thorax ○ Can't see the cardiac shadow § Pleural space is full of fluid □ Fluid is surrounding the cardiac muscle and it's the same opacity on a radiograph □ Border effaced the cardiac shadow and diaphragm (by disease process) ® Helps define pathology in most cases • Border effacement can be normal in some cases • Usually when you say border effacement, talking pathology

Geometric Effects

-Magnification Minimal problem in most images -Distortion - unequal magnification Long bone length Long axis needs to be parallel with the film to minimize this. -Distortion - positional Most common in the spine in the depiction of the width of intervertebral disc spaces • If patient on top of sensor, on right, left kidney won't be on • Magnification: patient farther from sensor than right on it • Most of the time, it's a minimally significant effect ○ Majority interpreted as normal feature of animal • If needed to do some precise objective measurement, need scaler of known size ○ Math to figure out magnification factor § Orthopedic surgery • Distortion is significant problem ○ Have object like long bone and one part of long bone is magnified more greatly than another part so it doesn't have appropriate shape and size throughout the structure of that bone ○ See most commonly in the long bones and that's because we don't have the long axis of the bone parallel with the surface of the sensor ○ Want long axis of structure parallel with sensor surface as much as possible • Another type of distortion typically identified in spine occurs when center of x-ray beam is not in good alignment with the object ○ The object is 3D and our image we are creating is 2D § Intervertebral disk space □ If we look at entire lumbar spine on laborador ® No way x-ray beam can enter every disk space parallel to the end plates of the vertebrae so we end up foreshortening or artificially shortening width of disk space ◊ Ends up giving false diagnosis of collapse of disk space • 3 ways to radiograph humerus • A: cranial caudal view • B: caudal cranial view • C: cranial caudal view • In every image, line not parallel to table surface • In every radiograph, we will display an abnormal length and distortional size and shape to that humerus because there's no way you can effectively get nice complete parallel alignment between humerus and tabletop • A is best if most interested in humerus because can move elbow up and down to get line more parallel but bone will be magnified because it's a fair distance away from sensor • Since we can put marker on of known length and calculate magnification factor, interested in getting parallel as we can as opposed to magnification A, B and C make different images of humerus--could mistake appearance for pathology

a. What specific area of the body is being evaluated with these images? b. What are the correct names of the views/projections in this radiographic study?

Abdomen - Same rationale for not using abdominal cavity as was given above for thoracic cavity. This consists of right lateral and VentroDorsal (VD) views. Notice in this case there is no DV or VD letter marker in the image. This is because the constant standard protocol for the abdomen is a VentroDorsal or VD.

Bone Loss (Resorption; Lysis; Osteopenia) What do we see?

Abnormal Radiolucency Decreased thickness A lag time for radiographic detection 7-14 days More Easily detected when: Focal vs Diffuse Compared to: Opposite limb or Adjacent vertebra Compared over time • Lysis pathologic change ○ Use for aggressive processes • Osteopenia: a little more benign and more long standing • Just like new bone, there's a lag time for bone resorption • In image, looking at maxillary arcade of dog ○ Teeth should be in firm bony sockets § No bone around fourth premolar so it's an area of lysis ○ Also lysis around 3rd premolar: look like floating in soft tissue ○ Radiographic diagnosis: mildly aggressive process § Don't think it's horribly aggressive § Could be seen with chronic severe periodontal disease and periapical abscess ○ No new bone: characteristic of dental abscesses If exam see soft tissue mass on gingiva, change etiology and make it more likely a neoplastic process; both needing biopsy to make final determination • New bone easy to see especially when periodontal • Bone loss difficult to identify especially when uniform effect in region looking at as the case for this particular dog • This dog had 2 year duration of L front leg lameness ○ Irregular bone opacity § Horizontal/diagonal areas of mineral opacity with a lot of lucency around them § Fairly diffuse and not very focal § Unusual length of lameness for neoplastic process • Radiograph other leg ○ Entire bone structure of LF leg had changed, not just focally § Cortex on L thinner § Same bars present on normal leg □ They are trabeculae but small trabeculae have been reabsorbed in abnormal leg ○ Made diagnosis of unknown cause; disuse osteopenia in single leg § Never resolved actual reason □ Could be neuropathy, etc. • Least likely: metabolic; they are systemic and symmetrical and diffuse ○ Most likely: neoplastic (could be neoplasm in soft tissue affecting mobility of leg) infectious • Any time there is change in bone, easier to identify when focal because have small spot • Compare vertebrae • Easier to see when compared over time ○ Recheck assessment

This is the lateral view from the recently adopted Pomeranian. Which femur is the abnormal femur in this lateral view of the spine and pelvic region?

Femur labeled B There are a couple of ways to determine which femur is R versus L. However for this dog 1 of those methods would not necessarily be reliable in this image. Method #1 - effect of Magnification. Magnification is the simple enlargement of an object because that object is moved farther from the image receptor (x-ray detector). In order to determine R from L femur (or any of the long bones) in this lateral (most long/proper naming is lateral-lateral) view of the caudal body we would have to know what side the dog was placed on during the positioning. Unfortunately there is no R or L marker to make that known for us. If this was a Right-to-Left Lateral (shortened to Left lateral) then the left femur would be closest to the detector and its diameter should be the smallest and the right would be the opposite. If this was a Right Lateral (full name would be Left-to-Right Lateral - remember that the full name describes the point or surface of x-ray entry followed by x-ray exit and the detector is at the exit) then the left femur would be magnified more so than the right femur. For an elective lateral view of the caudal body, often the standard is a R lateral, but in cases of lateralized pelvic or hip pain, the patient may be positioned with the non-painful side on the table/detector. Bottom-line is that the "down side" label is pretty important to identification of laterality. Method #2 - something anatomically unique is present in the affected side to allow determination of that side. This is the method that I used for this dog. Based on the VentroDorsal (VD) views I had determined that the right coxofemoral joint was luxated. So the expected radiolucent curved space for the right hip joint should be absent in this lateral view. A lot of you may not find that the lateral view of the pelvis is very useful for the hip joints because of the amount of summation but with intact hip joint spaces, the lucency of the joint space should be visible. In this Pomeranian only one of the hip joint lucent spaces is visible and thus the other one must be the luxated right joint. Also one femoral head is markedly cranially positioned compared to the other. Correlating with the VD views the cranially positioned femral head must be the right femoral head. The head can be followed to the femoral diaphysis and it is the femur labeled B in the quiz question. Here is a zoomed in view of just the hips with some labeling: Right femoral head - 3 white arrows Right acetabular cavity edge - curved dotted white line Left femoral head - double headed arrow Left femoral greater trochanter - dashed single arrow Contour of the left femoral head - solid curved line. The joint space for the left coxofemoral joint is then the curved lucency dorsal or around the left femoral head.

Choosing either enthesophyte or osteophyte fill in the blank for each statement.

In image A the arrow points to new bone formation best classified as an enthesophyte. Ths is the site of attachment of the flexors of the digits. An enthesophyte is formation of new bone (most often in the shape of a "hook" or curved extension of the new bone) originating at the sites of ligaments, tendons, or joint capsule attachments. In image B, the arrow points to new bone formation best classified as an osteophyte. An osteophyte is formation of new bone (often in the shape of a "hook" or curved extension of the new bone) originating at the periarticular/perichondral rim of bones of a joint.

2 Important points

In order to respond the bone tissue must have a viable blood supply. Bone resorption and bone production cannot occur in the absence of vascular supply. Osteoblasts - from mesenchymal stem cells (in periosteum & bone marrow) Osteoclasts - from fusion of circulating monocytes • Bone has to have intact blood supply to make new bone or take bone away ○ If it doesn't, it will sit there and won't do anything • Osteoblasts come from mesenchymal stem cells along periosteum and bone marrow where osteoclasts come from blood supply (circulating monocytes) • Image is CT study of horse mandible showing nice cortical bone in mandible on left and very radiopaque structure of tooth • On right side, can see new bone formation and note that it's not as hyper attenuating as what normal cortex is because it's not mineralized as intensely as original cortical bone ○ Dark section in center § It is just as radiopaque if not more as original cortex □ Why isn't new bone on top of this segment of bone? ® Because there is no blood supply in this segment of bone ® It's a sequestrum: dead piece of bone ® This horse had infection associated with tooth that caused separation of a region of the bone ◊ Isolated from blood supply ◊ Causes problem until removed ◊ Can happen in long bones as well ◊ Good example of fact that need blood supply to make more bone or take away bone

angular limb deformity: What direction(s) is the distal portion pointing

In the frontal plane = Valgus or Varus In the sagittal plane = Pro(ante)curvatum or Recurvatum May have torsion component = Internal or External • Looking in frontal plane ○ Valgus means lateral § (L) in valgus so it goes lateral ○ Medial deviation is varus • Saggital or looking at limb from side: ○ If looking from side, many of the limbs have slight curve to them in the first place ○ If more curved cranially or toward the front, procurvatum ○ If curving toward caudal: recurvatum • 3D printrs: print bone model of animal to practice doing cuts to put back in best normal anatomical position CT

lesions of panosteitis

Increased diaphyseal medullary opacity -Proliferation of medullary bone trabeculae and fibrovascular tissue -Microscopically no inflammatory cells Convex borders Border may efface the endosteum Variable sized lesions -Common close to nutrient foramen Smooth continuous periosteal new bone - in more severely affected Fibrovascular tissue becomes mineralized and allows you to see it radiographically

Signs of Joint Disease

Increased joint cavity volume -What can be seen? *Regional size and shape change centered at the joint *Soft tissue/fluid opacity (Increased opacity effect if contrasting fat) Earliest and often least well detected radiographic change How easy/difficult will this be to see in the hip or shoulder versus the carpus, tarsus, or stifle? • Signs of joint disease ○ If lucky and asked to look at with acute onset of lameness, maybe can see soft tissue change ○ Acute onset in healthy joint: don't see subchondral bone or periarticular change unless trauma with fracture • Only successful with soft tissues in areas where there isn't a lot of muscle • In hip joint if that animal has increase in synovial fluid in hip joint, won't see ○ Buried amongst muscle ○ Same thing with shoulder ○ In carpus, tarsus, stifle should see radiographically • If you have joint with some fat ○ Stifle joint ○ Top image: abnormal stifle § Changes with infrapatellar fat pad § Anatomically that fat pad lies between the outer fibrous layer and the inner synovial tissue of the joint § Fat: shade of darker gray § Normally fat is extremely close to the bone so it goes from inside visual margin of the patellar ligament almost to touching the subchondral bone § The only reason it doesn't touch subchondral bone is because there is thin layer of articular cartilage § Moderate increase in soft tissue fluid opactiy in joint because reduced size of infrapatellar fat pad § Caudally see triangle of fat between cranial border of gastrocnemius, caudal border of joint and more distal muscle related to popliteal tendon area § Those fat pads are very sensitive to increases in fluid and/or soft tissue enlargement within synovial joint cavity • Bottom image: ○ Similar feature in carpus and stifle (so does cat) ○ Fat pads associated with antebrachiocarpal and metacarpal joints Can determine if swelling is intracapsular or extracapsular

Altered subchondral bone opacity

Increased stress/load leads to new bone - thickening of the subchondral trabeculae (sclerosis) Penetration of inflammatory or infectious products through the articular cartilage causes lysis • Altered subchondral bone opacity • Lucency within subchondral bone on side that is more narrow ○ Disease in structure of joint due to: § Cystic process § Inflammation § Infectious inflammation or sterile inflammation • In area around the lucency, looks more mineral opaque: sclerosis ○ Sclerosis: increase in subchondral bone opacity Unique to that region of bone

New Bone Production What do we see? (location)

Location (where the osteoblasts are) -Periosteal -Endosteal -Trabecular -Subchondral Lag time between osteoid matrix formation & matrix mineralization 7-10 day in immature skeleton 10-14 day in mature skeleton • When making description, tell where you see that new bone. Subchondral: bone immediately deep to the articular cartilage • Waited 4 weeks to recheck because there's a lag time between formation of new bone and what we can see radiographically ○ Unless something unusual is happening with patient in terms of soundness or improving lameness after doing fixation, not a good reason to radiograph until you expect to see a change ○ Lag time is 7-10 days in immature skeleton and longer in adult • Should also give indication of what to do radiographically with patient with lameness, radiograph and see nothing (don't recognize any abnormality) so send home on conservative treatment and still lame ○ Smart thing to do with radiographic test: repeat radiograph § Puppy, foal, calf, etc. repeat sooner because more likely chance you will see something Adult: won't do any good unless you wait up to 2 weeks for change to show up

motheaten

Multiple lytic foci -Poorly defined to Discrete borders -Variable sized Cortical disruption? Periosteal new bone? Zone of transition? mage without plate ○ Abnormal area very mottled § No uniformity to the change in opacity ○ See areas of lucency § Mottled, stippled lucency § Don't have increase in mineral opacity occurring in that area □ Have areas where bone is going away • Moth-eaten: ○ Holes have fairly discrete borders but are fairly small ○ If moth was aggressive, holes may be close together and start merging but typically can see distinctness in area ○ How would you draw? § Little dots of black: moth-eaten area § Swath of black: more geographic • This dog has cortical disruption ○ Not sure if it's due to moth-eaten pattern because dog has pathologic fracture § Happened in pre-existing diseased bone • Zone of transition poor ○ That is starting to move towards a more aggressive type of processes as opposed to non-aggressive process • Sometimes patterns change or define selves more at different time point • This dog had fracture repaired with bone plate and screws ○ Did the small lucencies go away? § No they are bigger, maybe more well-defined, some merging together § This dog still has evidence of aggressive process going on § It is not chaotic □ Still has some form and shape to process • Missing new bone response associated with primary disease Hemangiosarcoma of the bone

Are all radiolucent areas in bone caused by lysis?

No! - Don't forget these possibilities!! Normal vascular tunnel Normal bone contours Normal cartilage Retained cartilage Relative lucency (Adjacent area is actually abnormally radiopaque) Summation effect • When seeing focal lucency, is it really caused by bone lysis? ○ Have to remember effects of summation ○ Lysis is destruction or dissolution of cells ○ Bone lysis is destruction of bone ○ Focal lucency associated with bone shadow in this dog Area of concern: • Different bone contours create different degrees of bone opacity through an area • Right coxofemoral joint: ○ Part of femoral head is apparently more opaque than another part of femoral head due to summation of dorsal rim of acetabulum • Normal cartilage exists ○ Cartilage in sacroiliac joint ○ Not area of luxation or lysis • Retained cartilage: ○ Distal ulna example and other areas of skeleton can have island of cartilage that doesn't mean anything clinical Not classically normal but not clinically significant

Based on your answer to #2 what are the other roentgen sign features of the abnormality?

Number: Multiple - but best to count confirming in both views - 10 in the lateral and 10 in the VD - YEA they agree! Size: Variable - largest is half the length of an L2 vertebra; smallest is less than 1/4th the size of the largest. Shape/Contour: Discoid to round & smooth to mildly irregular Margin: Well-defined Opacity: Faintly to moderately mineralized - but do not appear to be of solid mineral - have somewhat of an "egg-shell" appearance. Position/Location/Distribution: scattered from just caudal to the liver to the level of urinary bladder neck, ventrally and in right half of abdomen. But are they contained within the gastrointestinal tract or just in the peritoneal cavity? At least 5 are definitely not within shadows of the intestines. A really good question that might have been asked is - how can you determine that these mineralized opacities are not just superficial, i.e. like dirt in hair? Such determination requires you to use information from both views combined together. If these opacities were superficial they should appear to be outside of the abdominal cavity in one view. So if they were on the right side body wall they could appear to be within the abdomen in the lateral view but they would appear on the right lateral side in the VD view. But because they appear within the abdominal cavity in both views they must be in the abdominal cavity and not superficial.

permeative

Numerous foci of lysis -Most poorly defined -Variable sizes -Some coalescing Cortical disruption? Periosteal new bone? Zone of transition? • Permeative=invasive ○ Spreads all the way through without much confinement • Amorphous or poorly defined shapes • Through region of ulna and now in diaphysis and metaphysis of ulna, see lucency that is spreading without discrete shapes • New bone response • There are multiple areas where cortex is thinning and completely disrupted • Cortex thin and area of no cortex on medial aspect • No cortex on lateral aspect • Poorly defined as you go proximally • Mediolateral view (right) ○ Cranial cortex thin and caudally there is definitely disrupting ○ Zone of transition: poorly defined § Mounting evidence that this is an aggressive process and it's an active process as well

Assess the Roentgen signs for this leg. Roentgen signs are the categories of radiographic features used to describe how the anatomy is changed or differs from normal. Once you determine that the area/organ is abnormal you need to describe the change from normal using one or more (usually more than one) of these categories a. Position/Location/Distribution (Are the bones in their normal orientation to each other? Or if there is an alteration in the opacity or shape or margin where is it located?)

One way to approach the Roentgen sign is to express what it is that first makes you say that some aspect of the anatomy is abnormal. What first captured your attention when you looked at the images? In this case that is pretty easy. The parts of the elbow joint aren't fitting together correctly. So that leads to the MAJOR Roentgen sign being one of position/location/distribution. Notice that I made each of the Roentgen categories into a question - eg. In the images above, the elbow doesn't look as I expect, i.e. it is not normal. This is a good way to get started. Describing what or how the area of anatomy or the specific anatomical structure differs from the expected normal constitutes the RADIOGRAPHIC DESCRIPTION OR FINDINGS. Each normal anatomical structure is defined by its radiographic features - basically the same categories as above. Generally we reserve the use of the phrase Roentgen Signs to indicate the description of abnormal.

Juvenile Hematogenous Osteomyelitis

Osteomyelitis located in the metaphyseal and epiphyseal regions of the skeletally immature Vascular loops in the metaphyseal zones Discontinuous metaphyseal capillary endothelium Transphyseal vessels (large animals; not small animals) May be concurrent with septic arthritis Large animals most frequently associated with: Failure of passive transfer of immunity Systemic infections Umbilicus entry infections Uncommon in small animals • If there are bacteria in vessels, greater contact time of bacteria in metaphyseal region and it can increase the incidence that they will develop an infection at that location • Some vessels that go across physes ○ In large animals, not small ○ May explain difference in frequency to some degree • Hematogenous osteomyelitis somewhat more common in association with septic arthritis ○ Not always but can ○ Large animals more likely to have than small animals VERY rare in small animals ○ Tells you where to look at bone • Bone in carpal region OK ○ Soft tissue telling you not where lesion will be • Two bone lesions ○ Area of lucency in metaphysis ○ Area of lucency in epiphyseal bone on either side of physis ○ Width of physis normal ○ One area of cortical disruption where marker is ○ Lesions on medial side of leg because accessory carpal bone always lateral • On lateral medial view (right), a standard shot ○ Bone lesion difficult to identify ○ Summated too much to be as discrete as on dorsal palmar view on left Juvenile hematogenous osteomyelitis

Assessment points for normal hip

Position: >50% of the femoral head should be summated by dorsal acetabular rim shadow Shape: cranial acetabular concavity should parallel the femoral head convexity to the level of the fovea capitis (from fovea capitis caudally parallelism is normally lost Shape: smooth sculpted femoral neck to greater trochanter curve • First thing is amount of superimposition of dorsal rim over femoral head ○ If less than 50% some degree of subluxation • These criteria based on optimum position ○ Pelvis not obliqued ○ Femurs not rotated or abducted • Second is parallelism of subchondral bone ○ Femoral head has flattened area: fovea capitis § Ligament of head of femur inserts there § Because flat, not possible for margins to be parallel § Parallell zone lokoing for is cranial region of fovea capitis § Ideally convexity of femoral head should match concavity of acetabulum ○ Acetabulum rim incomplete and is filled in with ligament § Radiographic opacity of ligament is radiolucent so radiolucency caudal of femur head normal--where acetabular ligament is located • Shape refers to shape of contour from femoral head to greater trochanter ○ Should have sculpted curve to it ○ If concavity doesn't exist, probably filled in with bone--sign of secondary change developing image: • Right is normal • Left abnormal ○ Subluxated NOT luxated ○ Emphasized looking flat area § Easier to see because not tucked into acetabulum § Not pathological flattening of area of head ○ A little new bone on femoral neck ; not very concave as going from head to trochanter § Secondary changes that have started ○ Acetabular edge where cranial curve meets dorsal curve § Cranial effective acetabular edge § Point flattened

Boggs: 3 year old male-neutered Golden Retriever History: Enlargement at distal end of leg. No lameness but is slowing on the daily 2-3 mile run. Physical Exam: normal vitals. firm swelling at distal radius/ulna that is not painful to palpation.

Radiographic Diagnosis(es): 1. Moderately aggressive distal radius metaphyseal centered proliferative lesion. 2. Distal ulnar medial metaphyseal cortical metaphyseal concave defect. Etiologic Diagnosis (for each Radiographic Diagnosis & ranked by most likely to least likely): 1. Differentials for radius lesion are neoplasia such as a primary bone tumor (osteosarcoma or chondrosarcoma) and chronic low grade infections osteitis/osteomyelitis (such as mycotic infection). 2. Differentials for the ulnar lesion are secondary remodeling induced by the radius lesion or extension of the radial lesion into the ulnar cortex. Recommendations for further diagnostics (these should be procedures logically selected to resolve the diagnostic uncertainties left after the image study interpretation): The age of the dog is at the younger age peak (young peaking at 2-or 3 depending on source) for the bimodal age distribution of osteosarcoma. So a biopsy will be needed to make this definitive diagnosis. Mycotic osteomyelitis could very well look like this and thus if the owners want to step-by-step with diagnosis and do not want to biopsy first you could ask about travel within areas of the country endemic for the major mycotic organisms and submit a urine antigen titer. CT and MRI could provide a much better assessment of the portions of the bone involved and the overall extent of the lesion but will not provide a definitive cellular diagnosis.

21 month male-neutered DSH History: not using RH leg for 1 day. Owners were gone for 2 days and left cat indoors with another cat. George was lame when owners returned. Physical exam: normal vitals. very painful on palpation of inner right thigh when extending and flexing the leg

Radiographic Diagnosis(es): Right proximal femoral physeal simple fracture (Salter Harris Type I). Etiologic Diagnosis (for each Radiographic Diagnosis & ranked by most likely to least likely): Probable trauma. Recommendations for further diagnostics (these should be procedures logically selected to resolve the diagnostic uncertainties left after the image study interpretation): Radiographs are diagnostic for the fracture.

Common Patterns of Bone Responses: new bone production

Smooth vs Irregular -Lamellar -Palisade (columnar) -Spiculated (Sunburst) -Amorphous The feature smooth vs irregular is more critical than names of subtypes

What species is this and how do you know that?

So how should you know that this is a dog and not a cat? The general answer is you can tell by the differences in the appearance of the anatomy - shape of bone, shape and size of thoracic cavity, etc. For consistency in radiographic interpretation, I do advocate a standardized "hanging" protocol, meaning a standardized manner in which you hang analog films on viewboxes and the way you orient the patient regions on a digital screen. The rationale behind this hanging protocol is that it reinforces a systematic approach to image assessment. Additionally by looking at the images in the same orientation time-after-time you are training your eye-brain connection for pattern recognition. As the recognition of the pattern strengthens, you can increase your speed of assessment - faster pattern of anatomy recognition while still being able to recognize abnormalities in the pattern. This concept and the accepted standards are discussed/listed in the MK text on pp82-85 and in the Thrall text Chapter 5 page 82. To take anatomy review further, I could have added on to this question - What are the specific appendicular bones and joints included in these images? And your answers should have been: a. Shoulder joint or glenohumeral joint b. Humerus c. Elbow joint or cubital joint d. Radius e. Ulna Can you name the processes and protruberances of these limb bones? You will need to be able to do that. And a review of major muscle, tendon, and ligaments wouldn't hurt to do as well. Can you recognize the Deltoid Tuberosity? It is on the lateral surface of the humerus.

What are the correct names of the views/projections that were obtained for you to evaluate?

The names of the views were given as the titles of the figures in the MyPACS. The names designate the direction of the x-ray beam from point of entry to point of exit. There are fairly standard protocols for each area of the body. For the appendicular skeleton in the small animals, most of the view protocols are selected for the animal's comfort and to achieve a radiograph with the least amount of distortion of the projected anatomy. To achieve the least distortion the area of interest should be: 1) as close to the detector as possible and 2) the long axis of the bone should be as parallel to the surface of the detector as possible. For the elbow, the medial-lateral protocol puts the leg of interest on the x-ray table with the detector under the leg - the lateral surface of the leg is on the table/detector. The x-ray beam enters the medial side and exits to the detector on the lateral side. This protocol quite easily achieves the desired closeness and parallel-to-the-detector criteria to produce an image with little to no distortion of the anatomy. The cranial-caudal is typically done with the dog in sternal recumbency. The leg is extended and care is taken to put the long axis of the radius/ulna parallel to the detector while extending the elbow. The elbow should be positioned such that the tip of the olecranon is projected in the midline of the humerus. These views are described and illustrated in the MK text p70-71 and figs 2.41 & 2.42. The cranial-caudal view is the more difficult to achieve, with it not being uncommon for some degree of medial or lateral rotation of the elbow to be induced. Depending on what might be abnormal, some degree of obliquity in the cranial-caudal view may be tolerable. When looking at these radiographs, it is not possible to determine that they were done as medial-lateral versus lateral-medial and cranial-caudal versus caudal-cranial. There are no unique anatomical features that can tell you that; but protocol/standard dictates how they were obtained. If you think about trying to position the elbow region and detector in the opposite manner it would seem to be rather awkward.

A radiographic abnormlity is present in this view that is considered incidental (i.e. not clinically sigbificant to the preenting complaint which was a visible mass on the leg). Click on the abnormlity in the radiographic image to record your answer.

The white rectangle in the image shows where the "hotspot" was for a correct answer. Within this rectangle is the medially severely subluxated/luxated patella. It does not relate to the mass that was the reason for why the owner presented the dog to you. It may have some effect on the dog's gait but the owners were concerned about the enlarging mass. As best I could tell with where you made your various clicks, some of you clicked on the femur where the patella should be located. But really the femur is not abnormal, it is the patella that has the Roentgen sign of being in an abnormal position - so it is the patella that is the abnormality.

Is there a fracture in the region circled? Answer Yes or No. If yes, name the bone or bones that are fractured.

There are summations of the foot pad that create lucencies positioned with the 1st phalanges (P) of digits 3 & 4 that simulate fractures. When you look at these simulated fractures you can see that the border of the curved lucency extends outside of the plane of the bone - this would not be true for a fracture unless there was fragment displacement. The distal physes of metatarsals (MT) 3 & 4 are open and radiolucent and not fractures. The proximal sesamoid bones of the metatarsophalangeal joints superimposed with the distal MT epiphyses cause variation in bone opacity across the medial-to-lateral dimension of these epiphyses that simulate fractures. Some indicated a possible fracture in P2 of digit 3. The orientation of P2 and P3 of digit 3 at the distal interphalangeal joint is different than that of the other digits. This is the effect of positioning of this digit and the diagonal faint radiolucency at the distal axial corner of P2 of this digit is not a fracture but is the portion of the joint space between the ungual crest of P3 and P2. There is no soft tissue enlargement around this digit distally and that should be expected if there was an acute fracture. Reminder about FEET: The feet are comprised of digits and each digit is comprised of metacarpals or metatarsals and phalanges. There are 3 phalanges for each digit. So done confuse digits and phalanges.

The names of the views provided are Right Lateral and DorsoVentral. What specifically does each of these names tell you regarding: a) direction of the x-ray beam; and b) positioning of the dog?

a. Right Lateral i. Direction of the x-ray beam - the Fig 1 legend in the MyPACS is actually the most correct name using the "point of entrance followed by point of exit" of the x-ray beam standard for naming the views. The legend indicated that this was a "Left-to-Right recumbent lateral". This can be a cumbersome naming but it tells you exactly how the animal was positioned and the direction of the x-ray beam. Shortening of the view names and sometimes the use of abbreviations for the view names are used - BUT it is imperative that you know and understand what those shortened and/or abbreviated view names mean. 1. So in the long name: a. the first word = point of x-ray entrance into the body b. the second word = point of x-ray beam exit from the body and logically the location of the x-ray detector. i. If "recumbent" is added then it follows that the second word = that the patient was lying on the x-ray table or x-ray detector on that side. ii. If "standing" is added then it follows that the x-ray detector is held against that side of the limb or body surface. 2. In the shortened name: a. The use of right or left for head, spine, thorax, abdomen, pelvis means that the patient was lying on that side when recumbent or that the x-ray detector was held adjacent to that side if the patient was standing. b. For small animals almost all radiographs are produced with the animal recumbent. c. For large animals the majority of radiographs are produced when the animal is standing. ii. Positioning of the dog - the dog was lying on its right side. b. DorsoVentral i. Direction of the x-ray beam - the x-ray beam enters dorsal and exits ventral. ii. Positioning of the dog - the dog was resting on the table or detector on its sternum. This is ventral recumbency. Dorsal recumbency = lying on the back. • Without labeling (without R = right, L = left, DV or VD) in the views how do I know by looking at the image that this is a DV view? For the dog this can usually be determined by the appearance of the anatomy of the thorax no matter which view is obtained. The same is not true for the cat. This will be thoroughly addressed in the unit on the thorax.

Where do the bone regions start/stop from each other

a. The hardest of this to determine is probably between metaphysis and diaphysis. A couple of things come to mind. i. Cortical thickness. The diaphyseal cortex is the thickest. The cortex normally thins at the region of the metaphysis and then stays thin throughout the epiphysis. ii. Visibility of trabecular bone. These are the linear mineral opacities in the ends of the long bones. There are very few trabeculae visible in the diaphyseal medullary cavity. So going from the mid-diaphysis to where you start seeing more numbers of trabeculae is a good indicator that it is the metaphysis going into the epiphysis. iii. To the best of my knowledge there is not specific location in each bone for a clear-cut distinction. b. Obviously in the skeletally immature animal the cartilage of the physis separated the epiphysis from the metaphysis. When the physis closes it typically leaves a thin mineral opaque line where it was. This is more evident in some bone than in other. So this mineral opaque line is the differentiating level between epiphysis and metaphysis in the adult.

This patient has a 2nd abnormality that may not be as obvious. It can be most easily found by using comparison of anatomy features within this patient.

a. What are the paired organs that are visible in this region of the body? By paired, I mean that there are 2 reasonably identical or a matched set. By visible, I mean that you should expect to see them in the radiographs of this region of the body. So I was thinking of - ribs; pelvic bones; hip joints, kidneys, sacro-iliac joints. i. Are the individuals of these pairs similar or different in this patient? 1. ribs - similar; 2. pelvic bones - different particularly in apparent width in the VD view; 3. sacroiliac joints - different 4. hip joints - more similar than different 5. kidneys - more similar than different - particularly when you utilize both views i. If different, which individual of the pair is different from your perception of normal? 1. The right ilium is wider than the left; 2. The left sacroiliac joint space is lucent and the right is not visible. This effect on the lucency and width of the sacroiliac joint is totally positional and not due to subluxation or luxation. i. If different are they different most likely because of. patient positioning a. What are the organs or structures radiographically visible in this region for which there are multiple similar components? By this I mean, which organs or organ systems have multiples of them, not just matched pairs. Vertebrae; small bowel loops i. Are the individual components of these organs or structures similar or different in this patient? Some are similar and some different ii. If different, which one (or more) is (are) different from your perception of normal? L7 and S2 are different than their comparative vertebrae. iii. If different are they different most likely because of pathophysiologic abnormality PELVIS: Lateromedial and ventrodorsal (VD) views of the pelvis were obtained. FINDINGS: The patient is midly axially rotated in the lateral projection and the limbs are flexed. The right femoral head is displaced minimally dorsally and moderately cranially from the acetabulum. The right ilium is remodeled cranial to the original acetabulum into a shallow and elongated concavity immediately adjacent to the new position of the right femoral head. The left coxofemoral joint is subjectively normal. The right patella is medially located in the VD and lateral projections. In the lateral projection. There is a mild amount of smoothly marginated new bone extending ventrally from caudal L7. Additional osseous or soft tissue abnormalities are not identified. CONCLUSIONS: 1. Chronic right cranial coxofemoral luxation with formation of a pseudoarthrosis with the right ilium. The primary differential is secondary to past trauma. 2. Right medial patellar luxation, differentials are congenital versus traumatic. 3. Incidental L7 spondylosis deformans. After the quiz, I pointed out the change in contour of the right ilium where you see the concavity in the ilial contour and a rounded and mildly pointed projection of bone forming the cranial rim of the "new" acetabulum. This effect is due to the femoral head contacting this region during flexion and extension effectively creating a new "joint" surface on the ilium. This is called a pseudoarthrosis. Here is a zoomed in view of that region

Elbow dysplasia =

abnormal development of elbow -Ununited anconeal process -Medial coronoid disease *Fragmented coronoid process - medial portion -Osteochondrosis of medial humeral condyle -Ununited humeral medial epicondyle -Asynchronous radial-ulnar growth -Idiopathic incongruity -->mechanical dysfunction; synovitis; pain; secondary degenerative joint disease (DJD) Primary and concurrent flexor enthesopathy Fragmentation does not mean fracture; DEVElLOPMENTAL FRAGMENTATION of the bone. Most common but most difficult to recognize radiographically Enthesopathy: bone production where you see enthesophyte Digital flexor enthesopathy where thye insert on humerus (medial epicondyle)

This distal bone structure pointed out by arrow B is specifically called the

medial malleolus To answer this correctly you needed to determine/recognize: Region of limb anatomy = tarsus Medial vs lateral - there are several clues: Fibula is lateral; Tibial is medial; 4th tarsal bone is lateral This is a skeletallly immature dog - lots of open physes. The arrow is pointing to the distal tibial epiphysis which has the specific name of medial malleolus. The lateral malleolus is the specific name for the distal epiphysis of the fibula.

The bone structure pointed out by the arrow is the

patella Shape is the clue. It is highly likely that this dog has a luxated patella. There is rotation of the femur - based on the superimposition of the greater trochanter with the femoral neck - but this is quite an abnormal position for the patella, so I suspect it is also luxated and may be in large part the reason that the femur is rotated

Chondrosynovial zone or bone adjacent to joint pouches

• Fetlock joint of horse • This horse has chondrosynovial region change • See large, concave defect in contour of the palmar (front leg) aspect of fetlock ○ All related to proliferation of synovium in caudal joint pouch § Constant pressure over long period of time, signaling bone to remodel around it Also some soft tissue mineralization in that lesion as well

5 fundamental radiographic opacities

• Gas in intestinal tract and lung so they are blacker ○ May not be pure black but blacker than other areas • Fat • Astric is falciform ligament fat: darker shade of gray • Soft tissue fluid look identical to eachother • On a planar radiograph, can't differentiate fluid from soft tissue • Whenever you see opacity of spleen or liver • Location, location, location • Fluid has exact same radioopacity as soft tissue organs • Bone • See bone because it has mineral in it § If it didn't have mineral, would look like soft tissue • Metal in gastric lumen • Don't absolutely know they are in stomach-need orthogonal view Could be in L or R body wall and be superimposed

canine panosteitis variations

• Image 2: multiple small patches • L: larger patch • R: long zone of involvement • Periosteal new bone on caudal aspect of R • This disease difficult to make diagnosis of because doesn't have just one appearance to it • Common thread in appearance: increase in mineral opacity in medullary cavity Lesion of mineral opacity

hypertrophic osteodystrophy

• Left: normal ○ Normal mineral opacity in initial part of metaphysis § Very radiopaque □ Most intensively mineralization § When osteodystrophy occurs, first level happens as it should but then get zone of necrosis in bone. The lucency is the lesion, NOT the mineral opacity in the metaphsyis. § Similar when you look at ulna □ Normal mineralized cartilage to bone ® Proximal zone of necrosis to give lucency Lucency going proximally still physes; 3D bone flattened This lucency is physeal cartilage and it's normal

Tilting the ventral aspect of the pelvis to the left or right results in an asymmetry that will improve the apparent conformation of one hip joint and worsen the other.

• Orange line represents spinous process of vertebrae • Left: how it should be • If rotate pelvis such that pubis is going to the right, that definitely changes ○ Dorsal rim of left side more lateral so it looks like it's covering more head Right: thrown more dorsally and doesn't look like it's covering as much

more PennHIP

• Passive distraction or laxity ○ Difference in diameters between head, radius, and radius of acetabulum • If have tight fit, centers of one would be in center of other • More relaxed, center of head moves out of center of acetabulum • Research says that any dog breed with distraction laxity of 0.3 or less is extremely unlikely to develop hip dysplasia ○ Every breed is settling into own breed laxity or distraction index so that varies by breed ○ Rottweilers more lax in hip joint than gray hound ○ Distraction index where Rottweilers will not likely have hip dysplasia is higher than that of greyhound May have speciifc breed indices for normal

non-ionizing radiation modalities

• Radiation: passage of energy through space • Ultrasound: non-ionizing, mechanical energy passed through the body • The machine passes the energy through, comes back as an echo and that echo is picked up by the receiver and changed into digital and analog type of signal that we can then look at on a screen • Left: image of dog's adrenal gland • MRI: ○ Picture mode of NMR spectrum ○ Looking at magnetization of protons in body § Disturb protons, let magnetization come back again, pick up signal with radiofrequency signal that then goes through computer that makes it into a picture ○ Looking at brain ○ This dog has meningioma that can be seen in different planes ○ Beauty of MRI: soft tissue contrast § It is exceptional for demonstrating differences between soft tissues ○ It's a long study in terms of time it takes ○ Each plane has to be done independently Can't just gather a volume and reconstruct or reformat

moderate hip dysplasia

• Same dog as previous • Radiographic diagnosis: moderate hip dysplasia • Etiologic diagnosis: ○ Developmental orthopedic disease ○ Constellation of all the radiographic changes with the breed leads to radiographic diagnosis of hip dysplasia • First always look at positioning ○ Look at 7th lumbar vertebrae § Spinous process should be in midline plane of vertebrae § If have 6 and 5 even better to assure spine well positioned ○ Width of wings of ilia should be identical § If pelvis tilted, one wider than the other ○ Obturator foramina size and shape should be identical § Tilting pelvis changes shape and size ○ Patella should be on midline § Good on left and a little medial on right one--it was a little more internally rotated with the positioning ○ Ideally want long axis of spine parallel to long axis of each femur Right a little off but acceptable for assessment Severe subluxaton Mild remodeling of the cranial acetabular edge giving a wider open acetabular cavity. Caudal curvilinear osteophyte on each femoral neck

scintigraphy

• Scintigraphy • Scapula, ribs, spinous processes on top left • Top right is humerus • Not getting well-defined anatomy • Ghostly outline • Given IV injection of 99mTC tagged to phosphate-->through blood-->bone-->tags to area of active bone • Looking for areas where uptake is excessive • IV injection has made horse radioactive ○ Why GP's don't do this study ○ Special licensing tightly regulated by government ○ Keep in isolation stall for period of time until radioactivity goes to background ○ Put gamma camera in front of horse and that camera picks up radiation coming out of horse, converted to digital signal that is then converted to analog image for us to look at • X-ray beams don't make animal radioactive

Effect of summation of the perpendicular orientation of the columns of new bone

• This metatarsal has circular rings within it ○ This is dorsal plantar view ○ If had perpendicular view, circular rings would be columns sticking out of dorsal surface of metatarsal ○ Often when have new bone formation, maki

Joe case: "Joe" 3 yr Male German Shorthair Pointer History: 3 months of nasal discharge not responsive to antibiotics. Physical Exam: All normal except mucopurulent discharge predominately from the right nares. Is Radiography a good diagnostic test choice? Is there any negative to planar radiography for this dog?

• Unless you have endoscopy, only way to look inside nose • Should have a range of differentials for this dog, from rhinitis to malignant tumor ○ Young for malignant tumor ○ Mycotic infection ○ Foreign body • Disadvantage: if make poor quality radiograph it's basically useless Anatomy of skull difficult--need optimum quality radiographs negatives: • Have to anesthetize or heavily sedate for optimal radiographs of nasal cavity If referred to ISU, would immediately have CT study--more sensitive and specific information

bone development: endochondral

• Vertebrae all formed by endochondral ossification and feature of that is in the name: endochondral (within cartilage) ○ A cartilage model present initially, then sites ossification begin within that cartilage precursor § Method by which long bones elongate □ Physis is cartilage ® Within that cartilage, close to the epiphysis is the zone where the cartilage cells are multiplying ◊ Line up, as get closer to level of metaphysis, cartilage undergoes calcification, blood vessel bring in osteoblasts-->lay down new bone on top of calcified cartilage structures and then that becomes mineralized and turns into what we see as bone • Image at bottom of screen: ○ Fracture of distal humerus stabilized using implants ○ Most important: look at the change in the bone that's occurring over time § First image: □ On the ulna, no olecranon process visible ® It's there but it's just cartilage ◊ No mineral in cartilage so not radiographically identified ® Distal ulna: □ Radius: can see distal epiphysis § Second image □ Can see distal ulnar epiphysis and can see small ossification region in the olecranon process § Third image: □ More typical looking adolescent going to adult shape of styloid process of ulna ® Distal epiphysis □ Olecranon process getting bigger □ Shape of distal ulnar metaphysis flared ® Adult canine ulna doesn't look like that so it's all going to have to be remodeled into the adult shape as part of the normal growth cycle § All happening by endochondral ossification • Fair number of lesions that occur by defects in endochondral ossification ○ Developmental defects into early adult age § Failure of proper ossification changes related to epiphysis and physeal-metaphyseal zones • Be able to use terminology metaphysis, diaphysis etc and regions of parts of bone • Compact=cortical bone • Spongy bone=trabecular bone ○ Metaphysis and epiphysis • Physes=epiphyseal plate • Healthy bone has 2 processes that it can undergo ○ All changes in radiographs consequence of these 2 processes 1. Production of new bone 2. Resorption of existing bone • During growth phase, production exceeds resorption because it's making a lot of bone • Once maturity reached (physis closed) and no more growth, resorption and production equal ○ Balanced based on stresses put on bones every day, all the time ○ Walking around, stresses put on bone ○ In adult, no net gain in new bone or loss of old bone § Matches to keep structure

What is the ideal sample of choice for diagnosis of anticoagulant rodenticide intoxication in live animals?

Extended hip VentroDorsal pelvis VentroDorsal Extended hip Extended hip VentroDorsal femurs > For full credit for this part you needed to have some form of extended hip or extended leg. When the positioning of a joint influences the interpretation of the joint the name of the view should emphasize the positioning of the joint. Usually this is going to be with respect to flexion and extension, but can also be reference to abduction and adduction or to stress applied to the joint such as medial or lateral stress to demonstrate a palpated laxity of the joint. > A reduction in scoring was done if you only provided the abbreviation VD - proper name is not abbreviations)

dog locations of OCD

**Humeral head# *Medial trochlea talus Medial humeral condyle# (# Also commonly seen as a subchondral depression without fragmentation) Lateral femoral condyle Medial femoral condyle Lateral trochlea talus

Which imaging modality is best for evaluating esophageal motility?

. Fluoroscopy - This form of x-ray imaging is used for assessment of motion, such as esophageal motility, or respiratory motion, or cardiac motion with blood flow, and others.

Intra-articular calcified opacities (bodies)

-Avulsed cartilage or osseous fragments; -Osteochondral fragments of a severely diseased joint surface; -Synovial osteochondroma : Synovial thickening cartilage metaplasia ossification (Not to be confused with sesamoid bones) -Meniscal calcification • Sometimes intraarticular calcified bodies or joint bodies that show up on occasion ○ Sometimes clinically relevant ○ Other times an incidental finding § No clinical relevance □ Tend to know if patient had lameness or not associated with thtat particular joint ○ Can arise by avulsion of cartilage segment or osseous fragment that comes loose and stays in joint cavity § Cartilage and bone fragment: if embedded in synovial tissue, continue ot have nutritional support-->that body can further grow □ If cartilage, can undergo calcification and maybe progress to ossification § When embedded in synovium, called synovial osteochondroma □ Need histopathology to confirm • Don't confirm sesamoid bone with intraarticular bodies • In stifle, can have dystrophic mineralization of cartilage ○ Can have island of mineral opacity in location where you expect meniscus to be • Dog on right: shoulder joint ○ Osseous body within the caudal joint pouch § From a dog with osteochondriosis dissecans of humeral head □ Humeral had flatter on surface ○ When cartilage came off, moved and trapped in caudal distal part of joint cavity § Will not cause mechanical interference with joint movement □ Distal to articular surface □ Not lame as consequence of joint body in that locaiton ○ No normal sesmoid in shoulder • Left: cat ○ Multiple mineralized bodies in addition to patella, gastrocnemius, sesmoid, and popliteal sesamoid ○ No contoured deficits in subchondral bone ○ No deficits in contour where collateral ligaments insert ○ Possibly synovial osteochondromas and may or may not be caus eof clinical problem ○ Seen commonly in limbs when not evaluating joint for lameness--may be on edge of abdominal radiograph

Ununited Anconeal Process

-Failure of the anconeal process (apophysis) to fuse with the olecranon portion of ulna -Should be fused by 150 days (~21 wks/~5mos) -Large breed dogs most susceptible -German shepherds over-represented

Common Patterns of Bone Responses: bone lysis

-Geographic -Moth-eaten -Permeative These patterns types are not as critical as presence or absence of cortical bone destruction • Geographic: tends to mean big • Moth-eaten and permeative: going down in size ○ Terms of size and somewhat terms of border of area • Pattern names used a lot but are confusing and relative amount of visual overlap between moth-eaten and permeative • Of most importance is whether or not cortex of region is disrupted ○ Typically when see cortex disrupted, in something that's not fracture, tends to signal more aggressive process than non-aggressive • New bone: ○ Spiculated: sharp spikes ○ Amorphous: no recognizable structure; a mess ○ One of the most important features is whether surface is smooth or irregular § Smooth: more chronic and bone has though about process of making new bone Irregular: happening fast; more on unregulated side of things

Summation effects

-Positive = relative increase in opacity May simulate a mass May falsely interpret as pathologic opacity May falsely interpret adjacent region as abnormally lucent -Negative = relative decrease in opacity May falsely interpret as bone destruction (lysis) May falsely interpret as break in bone structure • These are the 2 kidneys of dog and they are summated in space • Absoprtion of one adds to absorption of another • Trap is that sometimes you visually create a mass at the superimposition or summation area Every time you see increase in opacity you didn't expect, have to consider it's summation artificat by other view • Negative summations ○ Gas good example § Summated/superimposed with structure and makes you think there is a lesion • History of trauma--may be looking for fracture in pelvic bones and there is radiolucent gap ○ Gas in rectum, not a fracture of bone • Intervertebral foramen ○ Doesn't have gas but has soft tissue in it ○ Sometimes mistake for it a lytic lesion in ileal wing § Know by anatomy that it is a summated structure

X-Radiation based

-Radiography (planar): X-ray film (analog), Digital sensor -Fluoroscopy -Computed Tomography (CT • Planar radiography: getting image that has 2 dimensions ○ No 3D perspective in any of these images ○ In order to get 3D perspective of patient, have to have minimum of 2, 2D radiographs § One perpendicular to the other ○ Orthogonal view: the VD view ○ Combining lateral and orthogonal-can identify spatial location for any abnormality we identify ○ Dog on left has mineralized calculi in urinary bladder, located in central region of urinary bladder in each of the orthogonal views ○ Image on right: equine metacarpophalangeal joint § Metacarpal and not metatarsal because the letter L □ L implies front leg □ If hind leg, should have been labeled LH § Fractures of both proximal sesmoids in mid-body of sesmoid and severe displacement of fragments § Additional base fracture of one of the sesmoids as well

Radiographic Densities

-X-ray beam (many x-rays) energy -Tissue composition Tissue Thickness Physical density Effective atomic number Ending result is Differential Absorption of the x-ray beam by the patient's tissues.

groups of joints

-fibrous (syndesmoses, sutures, gomphoses); teeth -cartilaginous (hyaline cartilage, fibrocartilage) -synovial

Ionizing Radiation Based Modalities

1. x-radiation based 2. gamma radiation based • Well done analog radiograph better in spatial resolution (how well defined borders are) than digital radiographs • Human error lessened and processing enhances edges with digital radiographs • Fluoroscopy ○ GI motility ○ Swallowing ○ Etc • CT / cat scan ○ X-ray imaging in slices ○ Has taken away the summation of all parts of the body together • In general practice typically don't do gamma-radiation based imaging ○ Do have in hospital ○ Scintigraphy over-arching name § Scintillation of light generated by x-ray □ Use to look at physiologic things as opposed to anatomical structure Poor resolution for looking at shape and borders, etc.

Bone's Responses to Insult or Injury

2 Responses: RESORPTION NEW BONE PRODUCTION Usually a combination, but one can predominate; predominance can change throughout the course of the disease • When bone insulted or injured, 2 responses ○ Bone resorption and/or new bone production § Both go on to some degree at same time but one may predominate over other § During course of disease process, it may shift □ May be resorptive to begin with then become productive at end or reversal might occur • Healing fracture: lot of new bone that forms in many calluses so get enlarged region of bone ○ Once fracture healed and animal starts using bone more normally, resorption starts to occur and moves it back, remodels back to more normal shape of bone § Slow process § Such would be the case for this radiograph □ Ulnar and radial fracture □ Radial fracture with bone plate and screws □ Don't stabilize ulnar fracture § Look at in 6-12 months, starts looking at normal ulna due to remodeling

How many sesamoid bones are present in the 4th metacarpophalangeal joint of the canine?

3 = 2 proximal palmar sesamoids and 1 dorsal sesamoid Based on some of the responses, I think some of you did not read this question carefully. It was asking for the number of sesamoids at only 1 of the metacarpophalangeal joints, not at 4 joints. So be sure you read all quiz/exam questions carefully.

avascular necrosis--bilateral or unilateral?

90% unilateral • Each has radiographically normal hip joint thus we can do comparison • Dog on L: ○ Not round ○ Not uniformally mineral opaque ○ Acetabulum has some shape changes ○ A little elongated ○ In process of making secondary changes visible • Dog on right: ○ Right head abnormal ○ Head no longer round ○ Not uniformly mineral opaque ○ Opacity of femoral neck wider/thicker than opposite side and more radiopaque in region of neck as you go down into diaphyseal medullary cavity • Hip joints not comfortable for the dogs ○ If don't sedate well, don't have optimal VD view • Soft tissue noticed on exam ○ Volume in effected leg compared to opposite leg

Which bones show the classical radiographic changes of panosteitis? Choose all that are correct

A - multifocal patches of increased medullary mineral opacity are present in the humerus. C - although there is summation of the femur with inguinal and preputial soft tissue and the os penis, there are patches of increased mineral opacity in the femoral medullary cavity. Additionally there is periosteal new bone at the cranial femoral periosteal layer of the cortex, that is a radiographic feature of more severe cases of panosteitis.

hip dypsplasia

Abnormal development of the coxofemoral joint NOT Congenital Is heritable but phenotypic expression markedly influenced by environmental factors Variable degrees of joint laxity seen as subluxation Leading to: Remodeling of the acetabular rim Periarticular osteophytes and enthesophytes Femoral head & neck Acetabular borders All changes of osteoarthritis • Subluxation of joint starts process off and leads to variable degrees of osteoarthritis, that being the problem when that starts happening • Lysis NOT part of process All breeds have been identified to have or develop hip dysplasia Any breed dog but more prevalent in > 30 lbs Has been documented in cats Clinical signs often expressed by 6 months Can be detected by some methods in dogs as young as 16 weeks Invariably leads to degenerative joint disease Poor correlation between radiographic changes and clinical expression of disease • Maine coon have greater disposition • Clinical signs variable to when expressed ○ May not be expressed at all, as early as 6 months, or as adult • Some schemes used for identification will not make determination until dog at least 24 months old ○ Phenotypic expression may take that long if not longer to become identified • POOR CORRELATION BETWEEN RADIOGRAPHIC CHANGES AND HOW ANIMAL GETS AROUND ○ Can have dogs with terrible gait and minimal changes ○ On flip side, a lot of older adult dogs for abdominal problems and hip joints included in image and can have severe degenerative joint disease and owner says they're getting along fine Self-adapted to process and not out running a lot

lamellar new bone production (single or multilayered)

Appears separated from cortex by lucent layer May blend/become solid with increased time • Can have single or multiple layers • Doesn't happen very often but can see on occasion • Zoomed out view of metacarpal and zoomed in view of region of new bone • Zoomed in region can see layers from cortex ○ More radiolucent-->radiopaque-->radiolucent-->radiopaque § Tells us that things have occurred in waves in way new bone has been formed • Surface is more smooth than it is highly fuzzy or irregular but still not super crisp so it's likely active • Depending on what caused this and time frame that you might see it and watch it over course of time, this could eventually all turn to uniform mineral opacity • If you can resolve disease process, might go away and wouldn't know it had been present • Dog with hypertrophic osteopathy ○ Don't memorize ○ Not how every one looks Orientation parallel to long axis of bone

What am I looking at?

Appendicular vs Axial Specific region Specific bone(s)

2 important points...2

Bone adapts to the loads under which it is placed meaning that bone adapts to the stresses applied. Increased stresses--> addition of bone Decreased stresses -->reduced bone • Change way we walk-->shape change in bone ○ May not be problem but could be detected in radiographic study if changed enough • Increased stress on bone: add bone • Decreased stress: takes away • As people age, more so in women, there is disuse osteoporosis ○ Bone becomes less bulky because not using it • Dog had premature closure of growth plates resulting in subluxation at elbow ○ If not corrected, dog will develop arthritis in elbow that may cause long term problems ○ To correct, surgeons did ulnar ostectomy (ectomy-remove) ○ Took out segment of ulna ○ Rechecked (always do to make sure elbow reaching congruency) § Distal ulna going away □ Tells us that ® It has good blood supply ® No more typical/normal stress going through ulna at that level ◊ Going from proximal ulna-->intraosseous ligament-->radius and majority of weight distribution Removal of ulna because it doesn't think it needs to be there anymore: example of disuse osteoporosis or osteopenia

Which dog or dogs have the radiographic features of an ununited anconeal process?

C: This is the only dog that exhibits an ununited anconeal process The other 3 cases are examples of superimposition of portions of the humeral medial epicondylar physis that is still open and casts is lucency with the contour of the anconeal process. What do you notice as being different in the positioning of A, B, and D, compared to C? C is positioned with the elbow in a greater degree of flexion than the other 3. Dog C still has an open olecranon process physis and is thus not a skeletal mature dog, but it is also not a very young puppy as in the case of dog B. But the added flexion of elbow C has moved the humeral medial epicondylar physeal lucency away from being summated with the anconeal process and thus the vertical lucency within the shadow of the anconeal process is a true lucency in the anconeal process and is typical of the ununited anconeal process. This stresses the importance of adding a flexed, and preferrably a hyper-flexed, medial-lateral view to your study when the clinical suspicion of elbow dysplasia due to ununited anconeal process is high.

Foal Angular limb deformity

Carpus most common Congenital Joint laxity Incomplete ossification carpal bones Acquired developmental Asynchronous growth across the distal radial physis Abnormal development of the distal radial epiphysis Abnormal development of the carpal bones

bone as tissue

Cells -Osteoblasts -Osteoclasts -Osteocytes Extracellular Matrix (Osteoid) -Organic = Collagen -Inorganic = hydroxyapatite Calcium Phosphorus Ca5(PO4)3(OH) • Body categorized as connective tissue • Osteoblasts: produce osteoid • Osteoclasts: remove bone from that organ • Osteocytes: adult; trapped in lacunae • Osteoid an ECM and if we were to have a radiograph of that ECM, it would not be very visible if it was in the body because it's only when it becomes mineralized/calcified that we are actually able to see ○ Keep in mind when you see area more radiolucent in bone § Could it be just area of osteoid matrix that isn't mineralized? Not necessarily a severe pathologic process. □ Will see if we look over course of early healing of bone fracture ® In beginning of healing, have some osteoid matrix formed that won't be mineralized

What can we detect radiographically?

Characteristic changes of an underlying disorder. Non-specific features of secondary DJD No abnormalities i.e., Normal radiograph Medium to Larger breeds of dogs Younger (4-18 mos) more common but Age at detection varies - depends on individual dog tolerance; type and degree of activity Males > Females • Often detect secondary arthritic changes then exclude one of the others • Do other imaging (CT scan, going to surgery for arhtroscopy) to make diagnosis.

Medial coronoid disease

Chondromalacia, subchondral bone avascularity Fissures, fragmentation Medium & Large breed dogs Males > Females Clin signs as young as 4-6 months Difficult radiographic diagnosis Most frequently by rule-out of other causes for elbow centered pain/lameness in the appropriate patient CT imaging • Occurs most commonly • Absolutely most difficult to diagnose radiographically • Typically by radiographs process of elimination ○ Exclude others that are obvious and there are secondary degenerative changes (osteophytes and entheseophytes) • Can lead to fissures or fragmentations ○ Website shows where they can occur • If did medial-lateral direction radiograph, wouldn't profile that lucent zone at all • If you did true cranial to caudal or caudal to cranial likely won't profile that lucency • CT imaging ○ More sensitive and definitive ○ Also know that on CT, because it's simply x-rays, don't see cartilage § Cartilage not a unique feature on a CT scan ○ Some of these elbows with arthroscopy are finding cartilage lesions not visible on CT ○ Ultimate diagnostic grouping is imaging then arthroscopy if clinical signs still fitting ○ Generally speaking on CT, have changes in shape and contour that are more suggestive that coronoid the problem

What affects ability to see a structure?

Contrast Summation Border effacement • Need contrast but have other problems with planar radiograph ○ Summation § Any radiograph sum of surface A through body to outside surface § Get overlapping of anatomical absorption Border effacement: something is the same opacity as what you want to see and is touching it

What are the displacement directions for the abnormal position of the right femoral head? Choose all that apply.

Cranial All 3 directional planes need to be considered but there may not be shifting in all directions. Definitely cranial and that is easy to determine from the VD view. Also definittely Lateral but that choice was not given. If you were writing a description lateral would need to be included. So what about Dorsal or Ventral? Those directions are not possible to determine from the VD view, it has to be determined from the lateral view. In this dog in the lateral view, you needed to decipher which of the shadows represents the right femur and right femoral head. Referring to the labeled image in the explanation for Q1, you can confirm the cranial. So for either dorsal or ventral the head would need to be either "up/above" or "down/below" the plane of the acetabular cavity to be determined to be dorsal or ventral. Based on where I identified the right acetabular cavity - the original cavity - it seemed like the femoral head was simply cranail to it. With respect to the terms - there are directional or positional terms and surface terms. With respect to the appendicular skeleton there is never a ventral surface. The only time there is a ventral directional/positional shift is when you are referencing the femoral head or humeral head position relative to the pelvis or scapula. Likewise an "up" directional/positional shift of the femoral head or humeral head would be a dorsal shift. All other directional/positional shifts (excluding femoral or humeral heads relative to their normal joint positions) would be proximal or distal; lateral or medial; and cranial or caudal or dorsal or palmar/plantar. For surface terms, the level at which dorsal replaces cranial is at the antebrachial-carpal (or radial-carpal) and tibial-tarsal joints. At this same level caudal is replaced with palmar for a front limb and plantar for a hind limb.

Based on your interpretation, which Etiologic category of disease is most likely the cause of this dog's radiographic changes?

Developmental - means happening to the structure as it is developing - does not imply present at birth or genetic/hereditary

Joint malformation

End stage of chronic disease -Developmental disease -Traumatic Congenital disease

Magnification

Enlargement of image relative to actual size.

In a cranial caudal view of the canine stifle being evaluated for lameness, mild narrowing of the joint space is a reliable radiographic sign of articular cartilage damage.

False - in the dog, the standard views are non-weight bearing and thus the width of the joint spaces in these images is not a reliable sign of true articular damage

The abnormality in this dog is equally visible in both views - T or F?

False It is only well seen in the DorsalPlantar view.

Chondrosynovial zone or bone adjacent to joint pouches

Focal Lysis - Pressure induced remodeling/lysis Synovial inflammation or tissue hypertrophy bone erosion Neoplasia • Shows the joint pouches of the stifle and where, if we have increases in fluid or increases in tissue, that can cause a pressure and thus an erosion at the area wheres the capsule attaches ○ Doesn't happen commonly in dog or cat but happens more commonly in horse • On radiograph, would be seeing where green arrows are ○ See altered contour in cortex of bone § More of a geographic effect, not typically moth-eaten or permeative Depending on how long or short of duration, could have well defined zone of transition associated and can occur from either benign or malignant soft tissue processes

angular limb deformity: goal of initial radiopraphic study is looking for potential cause

Fracture - acute or chronic effect Non-fracture Retained cartilage core Infection or systemic disease Relative degree of alteration Remaining growth potential Excellent situation to use comparative limb radiography Effects at the proximal & distal joints Subluxation Secondary degenerative joint disease • Radiographic setting for dog presenting with angular limb deformity ○ Primary goal to identify cause § Fracture that created or something else? § Potentially retained cartilage core or evidence of severe hypertrophic osteodystrophy that really did alter growth rate of physis? Infection? ○ If surgeon, looking to see what to detect and derive from anatomy to fix • Secondary parts Look at joints and see how they are being affected by process

To evaluate for correct positioning look for symmetry of:

Ilial wing width Size & shape of obturator foramina Femurs - long axis parallel to each other and the long axis of the spine Spinous process should bisect the vertebral body shadow And Location of patella to be within the central portion of distal femur.

New Bone Production What can we see? Increased mineral opacity

Increased Mineral Opacity -Increased volume on a surface -Increased opacity within a part • With fractures, expect to see increase in volume on outside (easier to see than increase of volume on inside) ○ Can happen on outside or inside • Because it's making more bone, radiographic opacity of that part increases ○ Can see on tibial fracture § Right: immediate post surgery § Left: 4 weeks later recheck □ On outside, can see new bone along majority of the length of that area of fracture zone and some on lateral as well as medial side □ Can see cortex defined by sharp edges on inside and outside □ Fracture gap starts to disappear □ Orthogonal view would be similar

CAUTION / CAVEAT

Is it really too opaque or is it that the adjacent area is too lucent? Is it really too lucent or is it that the adjacent area is too opaque? Ask these "either / or" question(s). >Think of disease scenarios that could cause either Differentials >Determine plausibility of the scenarios Ranked differentials.

speculated-columnar new bone formation

Irregular overall contour to new bone surface Spikes of new bone - more sharply pointed -Radiate from a central location; "Sunburst" variation • Contour more irregular, less developed • Another analogy is the palisade looks like if you ran fingers over, it would feel lumpy but wouldn't hurt • On spiculated, if you put fingers over surface, might poke fingers and it would be sharp • More chaotic in appearance • Image on left: has smooth columns and some sharp spiky columns ○ Difference in degree of change that is happening in one area of bone compared to other areas ○ Can't define cortex ○ Definitely aggressive • Right image: ○ Metatarsus of horse ○ Sharp points on some of the columns ○ Cortex of horse pretty much intact § Little to no disruption of cortex § Laid down on normal cortex ○ Need to attend to it but highly unlikely that it's something that will potentially end up a demise disease for the horse • Sunburst variation ○ Spiculated ○ Used to describe primary bone tumors § Not all have ○ Some infections can have • Patterns of lucency: ○ Remember they are simply descriptive; do not denote unique disease process ○ Just tend to denote activity, aggressiveness of that process Other things come into play to help get to which disease is most likely

hypertrophic osteodystrophy (metaphyseal osteopathy)

Large & Giant breeds Weimaraners, Great Danes, Labradors, others 2-7 months old (may have relapses) Typically febrile and quite painful Systemic illness - dysregulated immune system Variable etiology theories Autoinflammatory Nutritional - contradictory evidence; now considered not a cause Viral - vaccines may trigger or be coincidental Maybe genetic - Weimaraners Very characteristic radiographic changes Variable with stage of disease Bilateral symmetry!!! Most frequent in distal radius & ulna In severe cases all long bones involved Rare involvement of vertebrae • Looking at radius in one plane ○ X-ray beams adds up everything it goes through ○ See undulations occuring § That's why in the radius there isn't just single flat line--undulations associated with the normal anatomical shapes § Occurs in tibia, and to some degree in ulna Why don't have flat line for physes and flat lucency for necrosis of bone Calcified cartilage turning to bone-constituted mineral opaque line adjacent to physis

Assuming this view is placed on the screen in the standard manner, which femur is marked with the asterisk?

Left Stardard orientation on the screen for any VentroDorsal or DorsoVentral view of head, spine, thorax, abdomen, pelvis is to place the animal's right side on the viewer's left side and visa versa. When describing/discussing any anatomy or lesion in the radiographic image we always refer to the patient not to ourselves.

palisading new bone production

Maintains perpendicular orientation to cortex Irregular contour to the region of new bone Smooth surface to each column

features to be described for fractures

Location of fx line Completeness Number of fx lines Direction of fx line Character of fx fragments Relationship of fx fragments Soft tissue injury Associated joint injury • Often dramatic displacement between segments of bone • Look at quality of bone (health of bone in region of fracture) ○ Healthy or diseased (pathologic fracture) • Gas in soft tissue that indicates fracture is open ○ Break in skin=open fracture • No break in skin=closed fracture • Any associated joint injury? Effusion in joint? Fissure fracture that goes into articular cartilage

Border Effacement

Loss of distinct borders of 2 objects of the same opacity that are touching.

joint cavity opacity (synovial +/- menisci and intraarticular ligaments)

Lucent (relative to subchondral bone)

early stage of hypertrophic osteodystrophy (metaphysical osteopathy)

Lucent zone in metaphysis close to physis Normal bone opacity separates lucency from the physis

The single word radiographic diagnosis for this dog is

Luxation - and specifically humeral-radial and humeral-ulnar (but not radial-ulnar) luxation. This means complete incongruency of the joint surfaces or that none of the joint surfaces are in their normal alignment and apposition.

angular limb deformity in dog

Most common secondary to Physeal Type V of distal ulna &/or distal radius Also happens in distal tibia Tibial & radial effect may not be uniform across the physis • If growth plate wide (radial growth plate) can have trauma to part of growth plate • Don't have to have compression trauma to entire dimension of growth plate Can occur in one part which can result in difference in growth rate and result in angular deformity

Things to be aware of

Most confident if change is evident in all projections of the affected structure. Normal structural variations - egs. -Nutrient foramen = focal lucency & disruption of cortex -Normally thinner cortices in metaphyses & epiphyses -Accepted normal breed variations *Disproportionate bone shapes in chondrodystrophic vs non-chondrodystrophic Age related normal variations -Bone growth regions -Non-consequential degenerative changes Geometric effects of image projection

signs of joint disease: altered width/thickness of the joint space : narrowing

Narrowing - cartilage loss Most valid in weight bearing images Fairly unreliable in small animals • CAUTION: this is most reliable if patient is weight bearing ○ Cats and dogs § Joint space width on radiograph is not reliable for thickness or thinness of articular cartilage because they are not weight bearing when radiographing and may be applying traction to limb ○ Horses § Weight bearing on radiographs § Try to make uniformly weight bearing on limb so you can use width of joint space as indicator of articular cartilage thickness ○ Cattle § Some weight bearing, some not • Image: ○ Don't know which leg ○ Proximal interphalangeal joint § Narrower than metacarpophalangeal or distal interphalangeal § Interpret to be real based on differences and other changes present • Angle of beam can effect ○ Standing animals: try to have constant angle for every area ○ Small angles Sometimes change animal positioning

Enthesophyte

New bone at site of insertion of tendon, ligament, joint capsule, or fascia to bone. Enthesopathy • Bovine foot • Zoomed image: projections of new bone ○ Smooth ○ Hook like shape ○ Not coming from the periarticular regions ○ Cruciate ligament between the two digits: where cruciate ligament inserts on P1 (axial surfaces of P1's) § Enthesophyte: new bone (same shape as osteophyte but different location) at tendon, ligament, joint capsule or other fascia associated with muscle on the bone ® Shape and appearance: these ones look non aggressive ◊ Singular Smooth margins

late stage hypertrophic osteodystrophy

New bone blends with cortex & remodels to normal bone shape • As it continues to resolve, everything starts blending toether ○ Lucency in metaphysis gone If look at it at age 3, might now have no clue that dog had that pro

This feline has an obvious fracture of the radius. Your colleague also questions the presence of incomplete fracture in the boxed areas of the zoomed in image (bones are oriented the same as in the zoomed out images) with the lucencies indicated by arrows. Your response to your colleague is

No - both are caused by the perception error called Mach bands. A Mach band occurs as a percieved white or black line when there is a dramatic boundary change where the opacity associated with summated and/or highly contrasted opacities occurs. See Fig 4-5 of the Papageores reading assignment. This question comes from the reading assignment of one of the chapters from a prior edition of the Thrall text that has been available on Blackboard and was listed in the the reading assignments in the class schedule. Just a reminder that quiz and exam questions can come from the reading assignments even if I have not specifically covered that element/topic in lecture or lab/discussion.

Why Radiograph?

Non-invasive way to look inside the body. Simple way to look at the anatomy "under the skin" to demonstrate: 1. normal or 2. pathological changes.

Based on your answer to #4 what are the other roentgen sign features of the abnormality?

Number 1 - there is only a single or focal area of abnormality Size In the DV view the abnormal opacity has a diameter that is approximately 1 intercostal space wide Shape/Contour Round Margin Well-defined and smooth Opacity Uniform soft tissue - the variations are due to summation with other shadows. Position/Location/Distribution Caudal-dorsal right thorax, in the right caudal lung lobe at the plane of the 10th rib just over halfway towards the chest wall from the spine. It is not easily seen in the right lateral view.

summation

Objects in different planes are superimposed.

bone

Organ - providing Protection Support Movement Mineral storage Blood forming cells • Bone being organ provides support for soft tissues ○ 90% calcium storage in body so performs those functions and hematopoietic cells in bone marrow Those things can be dysfunctional with respect to that organ

Radiographic Assessment Methods of hip dysplasia

Orthopedic Foundation for Animals (OFA) [any veterinarian] Extended hip, parallel femurs Ventral-Dorsal view of pelvis through stifles Pennsylvania Hip Improvement Program (PennHIP) [only PennHIP certified veterinarians] Extended hip, parallel femurs Ventral-Dorsal view of pelvis through stifles Hip Distraction Ventral-Dorsal Hip Compression Ventral dorsal • KNOW FULL NAMES • OFA often not sent to OFA for evaluation • PennHIP must be sent to veterinarian ○ Can talk to owners but they do the assessment ○ Vet just does technical side ○ Orthopedic service doesn't talk to them about what has beens een Wait for results which are forwarded to owner

osteochondrosis

Osteochondritis dissecans (OCD) -Cartilage flap / fragment: radiographically visible only if calcified -Osteochondral fragment *Usually remains in close proximity to subchondral bone origin *May become dislodged and migrate within the joint cavity

healthy bone tissue: 2 processes

PRODUCTION & RESORPTION -During growth production >> resorption -After maturity resorption = production no net gain or loss of bone

judge positioning first

Poor positioning Abducted leg position Externally rotated stifles Oblique positioned pelvis This confuses the interpretation & either artifactually worsens or improves the apparent hip conformation. • OFA may or may not accept ○ "indeterminate" § Questionable things on there □ Shouldn't send □ Spinous process not in middle □ Wings of ilia different widths □ Obturator foramina different sizes and shapes Femurs abducted and externally rotated

aggressive zone of transition

Poorly defined / vague / long

What are the proper names for these views?

Proper implies the full name of the standard view based on the point of entrance of the x-ray beam followd by the point of exit of the x-ray beam - NO ABBREVIATIONS!!! Dorsal-Plantar Tarsus(variations of DorsoPlantar or Dorso-Plantar are acceptable. Do I really know by the appearance of the anatomy that this is a Dorsal-Plantar versus a PlantarDorsal? No not really, but Dorsal-Plantar is the standard manner of positioning. See Fig 2.58 of Mulhbauer and Kneller for illustration. I use tarsus here because the centering of the x-ray beam is on the tarsus. This centering should include some of the tibial/fibula and the metatarsals. Medial-Lateral Tarsus - this is the standard positioning and x-ray beam projection for small animals.

OFA method

Required view: Extended hip, parallel femurs Ventral-Dorsal view of pelvis through stifles Evaluation: Semi-quantitative & Subjective assessment of Hip conformation • Very commonly used for any lameness problem in upper pelvic limbs, not just OFA • Strive for this • Can reject poor quality images PennHIP more likely to reject image; OFA more relaxed

intermediate stage of hypertrophic osteodystrophy

Resolved lucency "Cuff" of mineralized tissue separated from cortex by lucent space (single layer lamellar new bone) lucency disappears then get new mineralized tissue on outside ○ This intermediate stag: new mineralized tissue not connected to the periosteal surface of the bone - gap space between bone and mineralized tissue § Looks like sleeve or cuff around bone

smooth (& solid) new bone production

Smooth shaped layer or bulge May be slightly fuzzy during early & active formation • Takes bone having a lot of control over what's happening to make smooth new bone formation ○ Calm process • Right side of screen: ○ Dirt on screen ○ If follow cortex, it's very smooth and bulges a little (still smooth) then goes back to normal smoothness ○ There is soft tissue enlargement: something not normal ○ Endosteal side of bone: can see it bulges as well § Non-aggressive § Not very active ○ May be 4-5 weeks old or a month old as it's remodeling ○ Benign and innocuous • Left image ○ Carpal region of dog ○ 2 shapes of new bone that both have smooth surfaces and pretty solid in terms of bone opacity ○ One on more distal aspect has cortical thickness appearance with medullary component § Not the normal shape of a metacarpal ○ Both of these are older, new bone formations Not new things that just happened 2 days ago; probably happened months or years ago

best views for ununited anconeal process

Standard (minimally flexed) Medial-Lateral Hyper-Flexed Medial-Lateral Cranial-Caudal should be done primarily to assess for concurrent developmental disease changes • Hyper flexed best ○ Radiolucent cartilage still active in dog's humerus and where medial epidcondyle will fuse § When superimposed with ulna, can simulate lucency in anconeal process □ If know lucency is there, identify separation in anconeal process in more standard mediolateral view • Normal in hyperflexed ○ Older without open physeal areas • Cranial caudal view or caudal cranial view not helpful in identifying lesion of anconeal process ○ Don't see silhouette of lucency

medial coronoid process views/projections

Standard (minimally flexed) Medial-Lateral Hyperflexed Medial-Lateral Cranial-Caudal Cranial 15-250 Lateral-Caudal Medial

Joint displacement/misalignment

Subluxation (May only be visible with stress views) Luxation • Luxation: complete disconnection between surfaces of joint ○ No touching, no congruency of articular surfaces at all • Subluxation: still partial congruency • Fractures: convention or standard for describing displacement is to describe displacement of luxated bone or bone where it's no longer supposed to be • Coxofemoral joint: displacement of femur Use all three directions if shifted in all three directions

Lucency - Lysis

Summation effect Cartilage matrix -Known physis -Reparative cartilage Fibrous tissue -Replacement in bone defect Non-mineralized osteoid Bone destruction

Increased bone opacity

Summation effect New bone formation -Periosteal -Endosteal -Trabecular Failure of bone removal

What soft tissue structures are likely severely damaged as a result of the elbow's abnormal orientation?

The collateral ligaments, oblique and anconeal ligaments, and joint capsule. This is an extrapolation/speculation as we cannot specifically see these individual soft tissue structures radiographically. Muscle is no doubt bruised but not as likely to be severely damaged as the supporting ligaments of the joint.

From 3-D to 2-D and back again

The patient is 3-dimensional Radiographic images are 2-dimensional depictions of 3-dimensional patient No true depth perception in any single image 2 orthogonal views minimum needed to get a sense of the 3-D During interpretation strive to mentally reconstruct the 3-D.

So I am guessing that you have decided that the articular surfaces of the proximal radius and ulna are not in the appropriate normal position with the distal articular surface of the humerus. What are the directions of displacement of the radius and ulna? (Rule of displacement description is to describe the position of the distal portion of the leg relative to the proximal portion of the leg.)

The radius and ulna have shifted together in a cranial-proximal-lateral direction (this answers the "where is it displaced?") such that the radial head and coronoid process are at the approximate mid-level of the supratrochlear foramen of the humerus (this answers the "how much is it displaced?"). The direction of displacement needs to be related in all 3 dimensions! For this dog the direction that caused the most question is the cranial displacement of the radius and ulna. In class I used the radial subchondral bone surface and compared it to the subchondral bone surface of the humeral condyle. By comparing it to the normal you can better appreciate this. Likewise look for the trochlear notch of the ulna - that part that articulates with the caudal portion of the humerus and it is definitely cranial to the caudal articular portion of the distal humerus. From any medial-lateral view you can determine the directions cranial or caudal and proximal or distal; from any cranial-caudal view you can determine the directions medial or lateral and proximal or distal. For your refresher/review the normal directional reference terms are: FOR THE LIMBS: A. "Up-to down": [No above or below, or ventral in a limb] a. Towards the body = PROXIMAL b. Towards the ground/floor = DISTAL B. "Side-to-side": a. MEDIAL b. LATERAL C. "Front-to-back": a. Scapula through distal radius/ulna "Front" = CRANIAL & "Back" = CAUDAL b. Proximal femur through distal tibia/fibula "Front" = CRANIAL & "Back" = CAUDAL c. Distal periarticular level of radius/ulna through toes Front" = DORSAL & "Back" = PALMAR d. Distal periarticular level of tibia/fibula through toes Front" = DORSAL & "Back" = PLANTAR Here is a website that provides a quick interactive review of these Directions and Planes. Their illustration is for the dog but it also pertains to the cat, horse, dog, etc. We'll add Axial and Abaxial direction to these later. http://vanat.cvm.umn.edu/anatDirections/ I have added normal medial-lateral and cranial-caudal views of an elbow joint for your comparison with the case images. This is obviously quite helpful to confirm your decision of how it is that the case elbow looks abnormal. As you may not always have a normal image to compare to, it is a necessity that you review to re-establish or strengthen your mental library of normal radiographic anatomy.

The major Roentgen Sign abnormality in this dog is that of a/an

The shape of the medial trochlea of the talus does not match the concave shape of the grooves (cochlea) of the tibia. See fig. 4.46 of Mulhbauer/Kneller for DorsalPlantar illustration. If I had given the options of 'size' that would have been true as well, the width of the medial side of the tarso-crural joint is wider than that of the lateral side and the size of the medial trochlea of the talus is not the same as that of the lateral trochlear ridge. In general the opposing surfaces of bones participating in a joint match so that they move easily - meaning that if the bone on one side is convex, the bone on the opposite side will be concave so that they "fit together". There are few exceptions to this with the most obvious being the distal femur and proximal tibia; but you know that there is a cartilage meniscus between these bones so that they do indeed move wel together.

Why did the radius and ulna shift together as a unit?

They are connected by soft tissues - primarily the interosseous ligament of the antebrachium. So why ask this question? Often with skeletal system lesions, we get too focused on the bone and forget to assess the soft tissue. But really we should be sure to remember that the bones and joints are part of the MUSCULOSKELTAL SYSTEM. Assessment of the soft tissues and finding them to be abnormal can indicate a potential location of an underlying or associated bone lesion. Conversely, the effect on the adjacent soft tissues with respect to a discovered bone lesion has to be considered for prognosis and management of the found bone lesion.

What specific region of the body is being assessed with this radiographic study?

This is a front leg. That is as specific as you can get. Some of you wanted to make this a right leg but anatomically there are no features to distinguish a right from left front. The cranial-caudal view can be flipped (mirror-imaged) to look like either the right or the left. This is a reason for utilizing limb letter designations to appear in the image - this relates to medical-legal issues. No doubt as the veterinarian seeing this patient you know by history/palpation which leg this is. And as the veterinarian assessing this patient you should know that this is a canine

What area of the body is being evaluated with these images?

Thorax or Thoracic region. Why not thoracic cavity? - If strictly using the word "cavity" that might get you to thinking that you only need to look at the organs/structures inside the cavity. Hopefully by thinking thorax or thoracic region it prompts you to remember to look at all of the radiographic shadows/structures in this region - that includes the part of the neck included, the part of the spine and limbs included, the part of the abdomen included, etc. In other words don't get only fixated on the things on the inside of the thoracic cavity.

What we are hoping for in the diagnostic image?

To differentiate organ/tissue A from adjacent organ/tissue B. Portrayal in the picture of the true spatial features and relationships of A and B. • If looking at kidney, want to be able to comment on renal cortex or pelvis ○ Can't do on radiograph • Don't want any kind of artifacts, geometry effects to make organ look abnormal when it's normal Don't want distortion

avascular necrosis of femoral head (Aseptic necrosis, Legg-Calves-Perthes disease)

Toy & Small breed dogs Clinical signs typically @ 10 months Unilateral most common (~10-15% bilateral) Extended VD of pelvis and both femurs to do bilateral comparison since unilateral most common • Get necrosis in subchondral bone of epiphysis • Depending on area involved, may or may not get collapse of bone because weakened • Blood supply comes back to that area, dead bone removed so that • Lesion of femur; any injury in acetabulum a secondary issue • At beginning of vascular insult, radiographically typically see nothing • If you follow carefully over course of disease process, might be able to pick up subtle areas of lucency but that only occurs when blood supply has come to bone • Because we have change in shape, change in width of joint space Not because a lot of effusion or fibrous tissue but because have remodeled shape of head then may get subluxatio in terms of movement of head from acetabulum and secondary new bone changes will start

Distortion

Unequal magnification of different parts of the same object.

How to determine Lesion's Etiologic Diagnosis?

Unique lesion features + known statistics for a given disease Biopsy - histopathology & culture Joint fluid analysis +/- culture of fluid Clinical pathology -Blood chemistry/electrolyte and/or hormonal assay abnormalities to support metabolic cause. -CBC -Antigen - antibody titers

radiographic findings of medial coronoid process

Unsharp cranial border Blunted/rounded border "Stair-step" misalignment of radial head to coronoid Visible fragment - rare Secondary degenerative joint disease: -Prox anconeal process -Osteophyte medial coronoid process -Subtrochlear sclerosis • Want minimally flexed because trying to look at area that is more identifiable when not fully flexed • Hyperflexed: picking out subtleties of enthesophytes that are forming ○ Classically form on proximal border of anconeal process ○ Need to get anconeal process out from summation with epicondyle • Cranial caudal view: looking for periarticular osteophytes • Oblique: ○ Cranial view with beginning part of position of x-ray move, move 15-25 degrees to lateral side of elbow § Attempt to pick out one of the lucent edges of the fragment § Sometimes successful • Unsharp cranial border: ○ Not helpful ○ On almost all elbows • Bottom line is looking for secondary degenerative joint process ○ Osteophytes, enthesophytes, subtrochlear sclerosis § On the distal portion of the trochlear groove of the ulna □ Between the anconeal process and the coronoid process □ More distal than proximal Depositoin of new bone but since within the trabecular bone and subchondral area, it's sclerosi sinstead of entehsophyte or osteophyte because in deep substance of bone

Bone Insults/Injury-etiologic differentials

Vascular Infectious/Inflammatory Nutritional/Neoplasia Developmental/Degenerative/ Deficiency/Drugs Idiopathic/Intoxication/Iatrogenic Congenital Autoimmune/Allergic Trauma Endocrine/Environmental Metabolic

non-agressive zone of transition

Well defined / discrete / distinct / short / abrupt

altered width/thickness of the joint space: widening

Widened - Early may widen with increased synovial fluid volume Loss of soft tissue support Ligaments Joint capsule Subchondral bone lysis Filling of cavity with fibrous tissue / hypertrophied synovium • Coxofemoral joint space too wide • Other signs of presence of joint disease ○ If really early, think about increase in synovial fluid § May be where it's useful to have comparative limbs • Bovine foot ○ Have two digits ○ When on the restraining table/tilt table, each digit under same degree influence of non-weight bearing ○ Compare two digits and make assessment of joint space • Loss of ligament support ○ Loss of joint space too wide • Lysis ○ Destruction of bone and cartilage to increase width Can fill joint with more tissue than normal and can make it too wide

Contrast -

Without contrast a structure or its parts will not be seen. *If subject contrast is poor must rely on system to try to improve -Change settings within system -Add something to enhance the contrast -Change to a different system ~CT instead of radiography for bone ~MRI instead of radiography for brain ~Ultrasound instead of radiography for urinary bladder • Without good contrast, structure can't be seen • In dog on top lateral image, gallbladder can't be seen • In bottom image, can see gallbladder • Picking up attenuation of beam in smaller ratio ○ Fluids look different than soft tissue • Helps see contrast by picking different modality • Fluoroscopy clip ○ Adding contrast to the dog's body so we can see the lumen of the esophagus § Barium § Iodinated contrast § Gas • Frequently different modality is more expensive MRI most expensive of all modalities to purchase and operate

How do you get the image?

X-ray Tissue Interaction • Either x-ray beam may go through patient without any interaction whatsoever--when that gets to sensor it creates areas of blacker color • It could also be totally absorbed by a body part of metal in body ○ That x-ray will not get to sensor and will be area of whiteness • It could also scatter and come out of patient in non-true anatomical direction ○ That gives rise to a loss of contrast and some exposure where we didn't want it to fall on our sensor • Most of what happens is that x-ray beam has partial absorption or partial transmission so end up with image that gives differential absorption of x-ray beam based on the qualities of the tissue • Qualities that can effect absorption are thickness of tissue ○ Thicker tissue absorbs more of x-ray beam ○ Tissues with higher physical density absorb more of x-ray beam and effective atomic number of tissue or substance is also more absorptive • The x-ray also has an effect: the higher energy of x-ray beam, more able it is to penetrate through body parts or tissues Combination gives composite image with differential opacities from differential absorption so it allows us to see different areas of the body

The directions of displacement of the tibial fracture are

a. *cranial* b. caudal c. medial d. lateral e. proximal - extremely minimal shift in this direction f. distal g. dorsal h. ventral Remember that the rule for naming the directions of displacement are to name the directions that the distal portions have shifted. LEFT TIBIA/FIBULA: Standard medial-lateral and cranial-caudal views were obtained; the latter included through the digits. RINDINGD: There is discontinuity (fracture) of the tibial and fibular cortices at the junction of the proximal and middle thirds of the diaphysis. The fracture plane is transverse with a caudal-lateral angulation resulting in a mildly longer caudal-lateral cortical length to the distal segment. The distal tibial segment is mildly displaced cranially and laterally. There is insignificant shifting of the distal fibula. There is mild uniform soft tissue enlargement in fracture region. All other bone, joint, and soft tissue structures are normal. CONCLUSIONS: 1. Simple, closed, transverse diaphyseal fractures of the left tibia and fibula with mild displacement consistent with the trauma history. 2. Mild soft tissue enlargement most consistent with traumatic hemorrhage. This young dog has numerous open physes - all are normal.

Select the portions of the bone organ that are altered by this lesion. Choose all that are affected.

a. *periosteum* b. *cortex* c. *endosteum* d. *medullary cavity* e. trabeculae - extremely few in the diaphyseal portion such that not considered a major portion in the diaphysis. However if you look at the normal long bones, there are a lot of linear mineral opacity shapes in the metaphyseal and epiphyseal regions which are the trabeculae. f. subchondral - refers only to the bone immediately deep to the articular cartilage. It does not refer to the bone adjacent to the surfaces of the physeal cartilage.

As you have no other information about the patient what can you deduce from the images?

a. Species and Breed? - canine; no idea about breed b. Gender? - no idea c. Age? - cannot be specific but based on the skeletal appearance it is likely substantially older than 12 months. This is based on the lack of visible growth plates (physes). Some other changes are present that are evidence of degenerative disease and thus indicative of an older dog - that may not be as obvious to you now: i. Small projections of new bone on the caudal edge of the glenoid rim of the right scapula; ii. Hook shapes of new bone on the ventral vertebral bodies of T11-12 through T13-L1 (we'll discuss these later as the radiographic diagnosis spondylosis deformans). d. Presenting problem and/or clinical signs? You might be wondering why this question, when as a veterinarian I would know why I was radiographing the thorax? And that is very true - you should have a specific question or questions that you want to answer by the use of the diagnostic imaging test. However, you may discover an unexpected abnormality and then need to formulate reasons for how/why the anatomy is showing that abnormality. The unexpected abnormality may prompt you to decide that you need to go back and look at the patient - revisit your physical exam; or need to go back to the owner and ask more questions. So for this patient it is very conceivable that there may be no respiratory or cardiac clinical signs or problems noted by the owners. It may be that this was/is a totally unexpected finding when radiographing the thorax as a pre-anesthetic screening for a dental procedure. Or it is very possible that the thorax was radiographed looking for dissemination or metastasis of a known malignant tumor. In either scenario, this is a very important finding - it is not incidental. This would need additional assessment and ultimately will likely need histopathologic and/or culture to determine its etiology. Looking randomly at some of the group documents there was a wide array of suspicioned abnormalities for this patient. I have selected one area to address a bit further: 1. One area that may have been questioned by some is a focal soft tissue opacity in the left half of the thorax (remember that we always refer to the patient's right or left, not our own) positioned from the caudal border of the 6th rib to the cranial border of the 8th rib. This has a well-defined lateral border, but with no defined medial border and a correlating soft tissue opacity with well-defined edges was not seen in the lung in the lateral view. Remember that the structures seen in a single view are the summation of the structure shadows from "skin-to-skin" in the perpendicular plane. So in the DV view the structures seen are the summation of the shadows from the dorsal skin surface through the ventral skin surface. Using the bone structures to help narrow your search for a shadow of interest can help in this situation. Relative to this soft tissue opacity, use the 6th-8th ribs and look from dorsal through ventral at this plane in the right lateral view and notice that there are similar size looking shadows profiled at the dorsal skin surface and ventral skin surface. So the apparent intrathoracic left caudal soft tissue opacity is one of these external structures. These cutaneous region bulges are most probably subcutaneous lipomas - one simply summating with the lung. It is deriving its well-defined lateral border in the DV view from its contrast with the room air. 2. General increased opacity in the caudal dorsal lung. I find this to be a common potential error for a lot of thoracic evaluations. One of the identification techniques that you want to use is to constantly compare and correlate between ALL of the views that you have BEFORE you make a decision/conclusion that an area is truly abnormal. So even though with the digital images you may have one view before the other you should avoid making your description and conclusions based on only 1 view. [Lecture and/or the Discussion I am likely to show you one view, it will be for emphasis of a particular feature. You can be assured that during my evaluation of the radiographic study I used all of the views that I had!] So in this thoracic study if you thought the caudal dorsal lung opacity was greater than normal in the caudal dorsal region, you should have immediately looked at the DV to determine if the separated right and left lung lobes in the caudal region looked abnormally opaque as well. In this dog the right and/or left caudal lobes do not have diffuse increased pulmonary opacity. So what you are seeing in the right lateral view is summation of the right and left lung structure - a majority of which is the vasculature. Also having an impact in the lateral views is your natural tendency to compare the caudal dorsal opacity to the cranial ventral region. Due to the shape and thickness of most dogs, the cranial ventral region will normally be more radiolucent than the caudal dorsal region. This case presented a bigger challenge than the elbow luxation with respect to finding the clinically significant abnormality and having confidence that it was real. Why? The thorax is a very much more complex region than the elbow, especially when you consider the number of anatomical structures that you need to evaluate. The complexity of summated anatomy requires more effort to "sift" through to differentiate normal from abnormal. This is not an area for success based on "speed reading" particularly at the beginning of using this diagnostic test. Because you had no biasing information - i.e., no history, clinical signs, or physical exam findings to give you a reason for obtaining thoracic radiographs - you really had nothing to guide you on a targeted search. You needed to rely on your knowledge of normal thoracic radiographic anatomy and the many variations of normal. • If you had been told that this patient had exercise intolerance and a heart murmur, you would have immediately targeted your search to the heart. Any subjective impression of abnormal cardiac size would need to be substantiated with co-existing shape changes and use of the objective measures - such as the Vertebral Heart Score (VHS) - again to be more extensively addressed later in the course. Some of you indicated that you had done the VHS. I got a VHS of 10 that is in the normal range for the general dog. Again when we concentrate on the thorax we'll revisit this objective criterion including the recognized breed specific ranges. • If you had been told that this patient had a malignant tumor, say on the leg, you would have targeted your search to the lung and you would have been looking for round soft tissue opacities - because you would have been looking for metastasis from the malignant tumor. So it definitely helps to have as much information as possible. • But on the other hand you also want to avoid the "tunnel vision" or satisfaction of search error.

As you have no other information about the patient what can you deduce from the images?

a. Species and Breed? - feline ( based mostly on the appearance of the vertebrae); no idea of breed b. Gender? - no idea from these images. c. Age? - skeletally mature d. Presenting problem and/or clinical signs? - not so easy to speculate; as the mineralized opacities are not in the bowel, they could be incidental and of no clinical significance. Worst case scenario abdominal pain, which could be expressed in a number of ways.

Radiographic Decisions about Bones' response to injury/insult.

active vs. inactive aggressive vs non-aggressive Radiographic features to aid in the decision: Presence vs absence of cortical bone destruction Character/pattern of bone change Margin of change Zone of transition to normal • When we see change in a bone as a consequence of insult of some kind, one big question is is it aggressive or non-aggressive process? ○ Aggressive: something like neoplasm or an osteomyelitis that is out of control and need to do something about it sooner rather than later • Is it active or inactive? ○ If active, then it means that you need to keep watching or intervene ○ If inactive, maybe a consequence of insult many months ago that takes a long time to reach normal if it ever will Make decisions based on features of new bone production and removal of bone process

Perichondral or Periarticular signs of joint disease

area at rim junction of articular cartilage and bone a shape or contour and size change of this margin New bone = Radiographic diagnosis of Osteophyte (osteophytosis) • One of the best signs of existence of joint disease in small animal is the existence of changes at the peri-articular or perichondral region ○ Region adjacent to the subchondral bone where the cartilage stops § Cartilage covers subchondral bone then stops and get to cortex § Where cartilage stops: periarticular or perichondral bone □ Where new bone starts to form when joint mechanically unsound • Stifle joint (top image) ○ Don't see much change ○ Looks normal ○ Very little periarticular change in joint ○ Had cruciate defiicent joint but secondary degenerative changes mimimal • Bottom image: ○ A lot more elongated, sloping to lateral tibial surface ○ Happening where cartilage meets the epiphyseal bone ○ Periarticular osteophyte • Multiple osteophytes: osteophytosis • Osteophyte is restricted for the periarticular zones

The Radiographic Diagnosis for the hip joints is?

bilateral subluxation The normal congruency of the hip (coxo-femoral) joint is that the convex curved surface of the femoral head subchondral bone should be parallel to the concave curved surface of the acetabular subchondral bone and the width of the joint space should be a relatively thin space. Positioning will have an influence on this matching or congruency. In the VentroDorsal (VD) view with the hips extended the exceptions to this are the location of the fovea capitis on the femoral head where the ligament of the head of the femur inserts. This is a flattened region and thus cannot be parallel to the acetabular curve. Also in the extended hip VD view the approximately caudal half of the joint space surfaces are not parallel. In the VD view with the hips flexed (the "frog-leg" view - the hips are variable flexed in addition to be variably abducted), the head is rotated within the acetabulum and its rounded subchondral contour becomes much more fully and evenly matched to the concave contour of the acetabular subchondral bone. In lateral views of the pelvis, the contours are better matched and the thin curved subchondral surfaces are well matched and thus the thin radiolucent joint space is seen as a thin curved relative lucency. In medial-lateral views of an isolated femur, the leg not being evaluated is rolled up out of the way which causes a rotation in the pelvis. In this type of view the hip joint of the evaluated femur looks different but still retains a normal matched contour with the acetabulum.

Which bone response dominates this lesion?

bone lysis - and the pattern is more permeative.

The radiographs show changes of _______ abnormality.

chronic Particularly in reference to the history of 1 day of lameness the lesions present are not acute. A fracture would be a reasonable working clinical differential and the mineral opacity in the caudal joint pouch might have been questions as a fracture fragment, but there is no defect in the bone contour to indicate where it might have originated from.

Bone lysis

destruction of bone

The bone region most affected in this lesion is the

diaphysis The 4 choices listed are the regions common to all long bones. Some bone also have an apophysis (like the olecranon process, the tibial tuberosity, the greater and lesser trochanters, and greater tubercle to name a few) which have their own ossification centers and apophyseal growth plates. An apophysis is a process for insertion of a major tendon.

synovial joints are

diarthrodial joints • Synovial joints ○ Pretty much all similar with different shapes § Same composition ○ Get used to talking about subchondral bone § Cartilage relatively radiolucent so can't make a lot of determination of health of cartilage on radiograph in synovial joint but if see lesion in subchondral bone, start considering that cartilage may be diseased as well • Joint capsule: ○ Soft tissue opaque and can't see individual layers or parts of joint capsule: just one soft tissue feature • Joint cavity: ○ Contains variable amounts of synovial fluid that looks like synovial soft tissue so they blend together • Some joints have intraarticular ligaments ○ Ligament of head of femur ○ Menisci in some joints § Don't see as independent shadows: look like synovial fluid and joint capsule • See periarticular soft tissues to advantage in some joints ○ Fat in some of joint regions and that fat can be useful • Image: ○ Equine metacarpophalangeal joint Know its metacarpo and not metatarso because the marker: single letter is front leg

Subjectively the length of this dog's humerus is not the same in these 2 views. This is most likely due to

distortion in B but not in A. Positioning of the cranial-caudal or caudal-cranial views of both the humerus and femurs frequently results in distortion of these bones resulting in a length that appears different than in the orthogonal medial-lateral view and in variable degrees of shape differences. Hopefully not to be mistaken for lesions.

Which of the following is not a synovial joint?

intervertebral disc space (glenohumeral, temporomandibular, middle carpal are)

articular cartilage opacity

lucent

There is an obvious abnormality present (there is something that does not belong). At your first look at these images what is the Roentgen sign that is most evident?

opacity Everyone will not key in on the same first evident change. Many of you had a first impression of a change in Number. That is ok and you would then complete your answer of "what is wrong about the number" by completing the roentgen sign descriptions of the abnormal number.

There are several abnormalities in this patient. There is 1 clinically significant abnormality present in the thoracic cavity. With your first look at these images what is the Roentgen sign that you think is most evident in the thoracic cavity?

opacity The lesion of clinical significance is a lesion with the major Roentgen sign of abnormal soft tissue opacity. This was identified by some in both sections. I have put an * in the abnormal opacity in the DV image above. You can go back to the MyPACS and evaluate it further. The rest of its features are listed in the table for Q4. But we also talked about why it is not clearly visible in the left-to-right lateral view. This is totally due to contrast effect. This dog is lying in its right side for the lateral view. There is a degree of compression atelectasis of the dependent lung in that position. [However you need to realize that this is not a total deflation of the lung!] Sometimes, but not always, the degree of atelectasis is enough to reduce the contrast for "highlighting" a structure or lesion of interest. So here is the situation where an additional radiographic test would be very valuable to confirm your suspicion of focal abnormal soft tissue opacity. The simplest is to change the patient's position to a right-to-left lateral (shortened term is Left Lateral). This will put the lung in question up and allow the greatest degree of inspiratory air volume to generate the contrast to see the lesion. The right-to-left lateral is now shown.

subchondral bone

opaque

joint capsule opacity

opaque (soft tissue)

periarticular soft tissues opacity (+/- fat opacity in a few joints)

opaque (soft tissue)

required for visibility of structure

optimal contrast: Difference in "signal" between structure of interest and the background and/or adjacent structure

Which of the following locations show/shows radiographic evidence of an abnormality?

periarticular bone - the new bone on the caudal aspect of the glenoid rim of the scapula is at the periarticular zone and is an osteophyte. joint cavity - The location of the mineralized opacity just caudal and distal to the humeral head is in the expected location of the joint cavity. biceps tendon - this courses through the intertubercular groove and thus should be superimposed between the greater and lesser trochanters in both views and will typically be more easily seen in the medila-lateral view 1. Some of you thought there was a lesion in the subchondral bone and I think I got the impression that 2 regions were being questioned; a. One perhaps related to a curved radiolucent line effect appearing to be in the central portion of the subchondral contour - represented by the dashed line in this zoomed in view. The lucency is actually a Mach band/line created by the summation of the lateral or medial distal extension of the glenoid rim. It is a summation effect. b. The second is a area of relative lucency at the caudal-distal most edge of the humeral head. It two is summated with portions of the mineralized opacity that is in the adjacent soft tissue. I think I have pointed to (between the arrows) the lucency that was being questioned. My interpretation is that this is not a lesion in the subchondral bone but one of summation. 2. Where is the periarticular osteophyte? For this you need to compare this image to a normal shoulder and the abnormal contour of the caudal margin of the glenoid rim of the case dog should become evident. How do you know whether the mineralized structure at the caudal distal aspect of the joint is in the joint pouch or in the extracapsular soft tissue? Because this was not readily visible in the caudal-cranial view, we don't know for sure. So I will use my best judgement as to the likelihood of where it is. Since I know that it is very possible for a mineralized body or for the synovium at this level to become mineralized, that is my highest level of suspicion. Had there been a concave or flattened shape in the subchondral bone of the humeral head it would have been a much easier decision

The bone opacity pointed out by arrow A is the

popliteal sesamoid__ NOTE OF IMPORTANCE!! - For any question similar to this when I am asking for an anatomical identification I want you to be as specific as possible - I don't want to have to guess what you mean. So an answer such as "popliteal" will not be correct. Simple popliteal doesn't tell me that you know that this is a sesamoid bone. There were a few responses that gave an opacity like soft tissue or bone as the answer. I interpret this incorrect answer to be one of not reading/understanding the question. The statement began with telling you that the arrow was pointing to a "bone opacity" so the opacity was defined for you. BESURE THAT YOU READ EACH QUESTION OR STATEMENT CAREFULLY SO THAT YOU UNDERSTAND WHAT TYPE OF ANSWER IS NEEDED.

geographic pattern

relatively large sometimes has discrete borders • Lucency has disrupted or destroyed cortex? ○ Key • Geographic=big ○ In purest form, whole area is radiolucent with very little to no mineral opacity within it • Right: ○ Horse distal femur and proximal tibia in stifle joint ○ Well-defined circular radial lucency § Border of lucency is extremely well-defined; very sharp □ Know where lucency stops ® Can see that there is faint mineral rim around the lucency ◊ Zone of transition: the interface between what you see as abnormal opacity and where you believe normal starts again ○ With geographic pattern, distinct or well-defined borders or sharp zone of transition ○ Subchondral; in bone, immediately on other side of articular cartilage ○ Subchondral medial femoral condyle is where lesion is ○ Non-aggressive lesion • Left: proximal humerus of dog in epiphyseal to metaphyseal region of proximal humerus ○ At proximal end of lesion can see discrete border ○ Some of the other borders of lucency are not quite as well-defined ○ More uniformly radiolucent than it is stippled or mottled in its lucency ○ Cortex of the humerus (caudal humeral cortex) has been disrupted and broken there Even though it has geographic feature, probably an aggressive lesion in proximal humerus Cortical disruption? Periosteal new bone? Zone of Transition?

Gamma-Radiation based

scintigraphy

. The Etiologic Diagnosis for this mass is

the mass is of fat quality. And histologically after surgical removal this was classified as a lipoma. Fat has a unique radiographic opacity and thus very much aids in identification of it as a cause of a palpated mass. Clostridial cellulitis with abscessation - gas from colstridial infection mixed with suppurative fluid of an abscess could resullt in an intermediate gray opacity similar to fat; however the gas is frequently more easily seen and with this type of infection, the patient should have been severely lame and probably systemically ill, which was not the presentation for this dog. c. Rhabdomysarcoma d. Fibrosarcoma c and d choices are both soft tissue and thus would have no distinct borders contrasting with the surrounding muscle. There would be border effacement.

zone of transition

transition between diseased bone and normal bone

1. In the normal elbow, which bone is located most medially? a. Radius b. Ulna

ulna A bit of anatomy which I hope you remembered. At the elbow, the radial head is lateral and the ulna is medial. It is reversed at the level of the carpus - the distal radius is medial and the ulnar styloid process is lateral.

CT

• 3 acquisition images ○ Gives volume of numerical data that runs through computer, then computer does assigning of gray scales, etc. • Top left looks different from one on bottom, but same collection of data • Didn't have to do 3 scans through dog, did 1--because accumulation of data, computer can assign different kinds of gray scale ranges, etc. • Top: ranges for soft tissue • Bottom: ranges for bone • Soft tissues not well defined • Bone overly white when looking at soft tissues (attenuating is term for white for CT) • Don't see good structural anatomy of bone so have to play with in different ways • Volume we have collected so can ask computer to reformat that volume in different anatomical planes • Have dorsal plane and sagittal plane • Because we have volume, can ask it to do some 3D rendering and can ask it to assign color to the gray scale • Have a head (red one) with soft tissue looking like muscle color and bone looking more like bone color Use different facets to look at different things

PennHIP

• 3 required view for PennHPI ○ Extended HIP view ○ Distraction view § Every one has to be identified with unique veterinarian number and distractor number (unique to veterinarian) ○ Purpose is to induce passive laxity in joint and that is measured and correlated with previous research ○ Compression view § Can use whatever you have available ISU uses liter saline bodies with concave depression that fits at hip level

bone development: intramembranous

• Bone develops in 2 manners and in 2 regions of body 1. Intramembranous bone formation: type of bone formation in flat bones i. Skull 1) Area within CT, mesenchymal tissue starts to form ossification center and that expands by appositional deposition of osteoid matrix and becomes mineralized ii. Also occurs in fracture healing 1) Aka woven bone formation • Image is chinchilla Large tympanic bulla

fluoroscopy

• Bones are black • Lungs and air in trachea are white • Has to do with electronics of fluoroscopy system ○ Inverts densities ○ On radiographs, bones white and lung/air black • Interested in esophageal motility in this dog ○ Eating problem ○ Gave liquid barium (very x-ray absorptive so very black) ○ Can watch in real time the passage of barium through esophagus and into stomach • Can see heart beating ○ Watching physiological function • If concerned about structural features like vertebrae--don't use this. Use this for motion-following path of barium through esophagus or if interested in course of flow through vessel. Use if doing cardiac intervention-occluder for PDA