OCS: Indications for MSK Imaging

Match the fracture or pathology with its common name. 1. Keinboch's Disease 2. Bennet fracture 3. Nursemaid's elbow 4. Monteggia fracture 5. Scapholunate gap

1. avascular necrosis of the lunate 2. base of 1st MC fracture 3. radial head dislocation 4. promixal ulna fracture with radial head dislocation 5. Terry Thomas sign

What is the pathology? - 2nd MT stress fracture - Morton's neuroma - Gout

2nd MT stress fracture Correct, the increased calcification and a true fracture line through of the 2nd metatarsal are indicative of a stress fracture.

You're looking at lateral view of the C-spine and notice an increased atlantodental interval (ADI) of 6.0 mm. You think there is problem because you know that an ADI as little as _____________ is indicative of instability. - 3.5 mm - 5 mm - 6.5 mm

3.5 mm Correct, this is the distance that is first considered pathologic for upper cervical instability of C1-C2.

Although you can't visualize the rotator cuff on plain X-ray, you can assume a complete cuff tear from superior humeral migration. Normal subacromial space distance should be: - 7-10 mm - 3-5 mm - 1-3 mm

7-10 mm Correct, when measured on X-ray, the superior aspect of the humerus should be within 7-10 mm of the undersurface of the acromion to be considered normal.

Select the appropriate choice for order of most to least radiolucent biologic tissue. - Air, fat, water, bone - Air, water, fat, bone - Bone, water, fat, air - Air, water, fat, metal - Water, fat, bone, metal

Air, fat, water, bone This is the correct sequence of radiolucency of biologic tissue

In the ABCS of interpreting images, the "A" stands for: - Alignment - Air - Adjacent structures

Alignment Correct, this is one of the ABCS for viewing images. It pertains to normal anatomic alignment and shape of the structure in question.

Which variable is not a factor that would influence imaging of your patient? - Scatter - Size of body part - Motion - Distortion - All of the above items influence imaging

All of the above items influence imaging

Which X-ray view would you order to best evaluate the ankle mortise? - Ankle AP - Ankle oblique - Ankle lateral

Ankle oblique Correct, Sometimes called a mortise view, the small rotation of the ankle from a true AP projection allows for best viewing of the medial and lateral clear space of the talocrural joint as well as better visualization of the talar dome.

The thoracic spine is a common site of wedge, or compression fractures due to osteoporosis. In which column of the spine are these fractures typically considered stable fractures? - Anterior - Middle - Posterior

Anterior Correct, the anterior body is compressed due to compression forces.

The Ottawa foot rules tells you that x-rays are required in cases of acute trauma with pain in the midfoot zone, inability to ambulate and bony tenderness to which two specific areas? - Base of the 5th metatarsal or talus - Navicular or medial cuneiform - Base of 5th MT or navicular

Base of 5th MT or navicular Correct, the clinician must palpate these two areas as described in the Ottawa foot rules for consideration of imaging in the patient who has injured his/her foot.

Which imaging modality uses markers to measure metabolism and blood flow and is used in early detection of stress fractures and skeletal metastases? - Bone scan - Plain X-ray - MRI

Bone scan Correct, the bone scan displays the physiology of bone and serves as an early detection for stress fractures.

Which imaging modality is best for suspected posterior pelvic ring fractures? - Plain X-ray - Bone scan - CT scan

CT scan Correct, the CT is more sensitive and specific for viewing suspected pelvic ring fractures.

You are evaluating a 20-year-old male patient with an acute C-spine injury that you are seeing in your direct access clinic. The injury occurred during an intramural softball game he played in about an hour ago. He reported running directly into another player after laying out for a fly ball. He said he was going rather fast when he hit the other person, he thinks he hit the crown of the head first and had immediate midline tenderness. You know to apply the Canadian C-Spine rules and decide this qualifies as a dangerous mechanism of injury. Which is the most appropriate plan of care regarding imaging in this patient? - Cervical spine plain film series - Immediate MRI first to evaluate soft tissue - CT scan to best evaluate bony pathology - No imaging is required

Cervical spine plain film series Correct answer. Cervical spine plain film series is the most appropriate first line imaging modality.

You are examining a 25-year-old female with an acute episode of LBP located at the left L4-S1 region radiating into the left buttock x 10 days, no trauma reported. Her ODI score is 38 and her FABQ (work) is 10, FABQ (activity) 3. Upon physical examination you note ROM of the lumbar spine is limited in flexion with symmetrical hip IR of 25° in prone. No red flags with history or physical exam. She is asking for an MRI. According to ACP Guidelines, what is appropriate for imaging at this time? - Explain that no imaging is necessary at this point. - Explain that an MRI is inappropriate and order plain X-ray of lumbar spine. - Order an MRI per patient request. - Ordering both plain X-ray and MRI is appropriate at this point.

Explain that no imaging is necessary at this point. Correct answer, guidelines state that this patient doesn't require any imaging at this point.

The most common fractures of the hip occur secondary to osteoporosis, and are typically located at which area of the hip? - Femoral neck - Acetabulum - Greater trochanter

Femoral neck Correct, the femoral neck is the most common site of hip fractures due to osteoporosis.

Match the fracture with its common name. 1. Segond fracture 2. Jones fracture 3. Lisfranc fracture 4. Maisonneuve fracture 5. Salter-Harris fracture

Fractures: 1. Segond: Avulsion proximal lateral tibia 2. Jones: Fracture to the base of the 5th MT 3. Lisfranc: Tarsometatarsal joint fracture 4. Maisonneuvre: Malleolar fracture with spiral fracture proximal fibula 5. Salter-Harris: Epiphyseal fracture

A fracture of posterior elements of C2 with or without spondylolisthesis is commonly known as a ________________ fracture. - Chance - Hangman's - Jefferson

Hangman's Correct, given its name for the fracture occurred during a hanging-type injury, accidental or purposeful. *Chance fracture is given to fractures in the lumbar spine, also called "seatbelt" fractures.

The advantages of using Computed Tomography (CT) as an imaging choice includes all of the following except: - Provides high detail of anatomy - Provides for accurate measurement of anatomy - Is less expensive than MRI - Lower radiation dose compared to plain X-ray

Lower radiation dose compared to plain X-ray Correct answer, CT has a much higher radiation dose than plain X-ray

Which imaging modality is best to evaluate SLAP lesions and other articular cartilage defects? - Bone scan - MR arthrogram - CT scan

MR arthrogram Correct, because of its high sensitivity and specificity for SLAP lesion, the MR arthrogram is the modality of choice for evaluation.

Although plain X-ray is considered to be the first line imaging modality for cervical trauma, what imaging modality is best if you are suspecting soft tissue injuries/ instabilities and/or disc pathology? - Bone scan - Ultrasound - MRI

MRI Correct answer. By far, the best imaging study for soft tissue (disc, ligaments, spinal cord, etc) is the MRI.

Using the same patient scenario from above in question three, let's say you ordered plain X-rays and they came back as normal. You are still concerned about ligamentous injury. Which imaging modality do you order now, assuming all are available to you? - MRI - CT Scan - Bone scan - None, no imaging modality details ligamentous injuries well

MRI Correct answer. The MRI is the best imaging modality to evaluate ligamentous injuries.

When considering imaging studies for lumbar pain, research shows that the modality that offers the highest sensitivity and specificity for detecting cancer, infections and HNPs is: - MRI - Plain X-ray - Bone scan

MRI Correct, the MRI is an excellent modality for soft tissue disorders.

What is the best imaging modality to assess ligamentous or meniscal injuries of the knee? - Plain X-ray - CT scan - MRI

MRI Correct, the MRI is the most sensitive and specific imaging modality for soft tissue injuries, to include meniscal and ligamentous pathology.

You are suspicious of a space-occupying lesion into the cord. What imaging modality is most appropriate next? - Bone scan - MRI - CT scan

MRI Correct, the MRI is the most sensitive and specific imaging modality for soft tissue lesions.

Place the imaging modality in order of lowest to highest radiation dose to the patient. - MRI, CT scan, plain X-ray - Plain X-ray, MRI, CT scan - MRI, plain X-ray, CT scan

MRI, plain X-ray, CT scan Correct, MRI does not use ionizing radiation and therefore has no radiation associated w it, followed by plain film, with CT the highest due to its use of multiple X-rays images to produce its series of images.

As an object moves toward the source of the x-ray beam, its shadow becomes larger. This is known as: - Scatter - Magnification - Distortion

Magnification Correct, images project larger the closer they are to the beam.

Clavicle fractures are common, with most of them occurring in which portion of the clavicle? - Medial (sternal) end - Middle 1/3 - Lateral (acromial) end

Middle 1/3 Correct, middle portion clavicle fractures make up 80% of all clavicle fractures.

According to DoD/VA Clinical Practice Guidelines, plain X-rays are not recommended for routine evaluation of acute LBP within the first month of symptoms unless red flags are present. Which of the following is NOT a red flag for imaging? - Recent significant trauma (any age) - History of prolonged steroid use or osteoporosis - Mild trauma, patient over 30

Mild trauma, patient over 30 Correct, mild trauma in a young patient is not considered a red flag and does not warrant imaging within the first month of care. *History of prolonged steroid use or osteoporosis: both conditions result in bone demineralization, both are considered red flags for imaging

Which of the following is not a normal variant on plain X-ray of the knee? - Bipartate patella - OCD lesion - Fabella

OCD lesion OCD, or Osteochondritis dessicans, is a defect in the articular surface in the joint. Typical site is the weight bearing surface of the medial femoral condyle.

What is the pathology? - Salter Harris V of the tibia - OCD medial talar dome - Weber B of the fibula

OCD medial talar dome Correct, the medial talar dome has lost its congruency and has collapsed leading to a diagnosis of an OCD lesion.

Which cervical spine X-ray view would you order if you wanted to best view the intervertebral foramen? - AP - Lateral - Oblique

Oblique

Which lumbar imaging view would you order to best observe a pars interarticularis fracture (Scotty dog)? - AP - Lateral - Oblique

Oblique Correct, the lumbar oblique view is the view of choice to best evaluate a pars defect.

Which of the below radiographic views would you order if you suspected a Jefferson fracture? - Odontoid - Explanation - Swimmers

Odontoid Correct, also called an "open mouth" view, this view allows for best viewing for the Jefferson fracture of C1.

This is also known as tibial tubercle apophysitis that typically occurs in teen-aged boy and girls. - Sinding-Larsen-Johansson syndrome - Osgood-Schlatter's disease - Ewing's sarcoma

Osgood-Schlatter's disease Correct, this is a result of an overuse injury in children, typical is self-limiting and treated with rest and education. *Sinding-Larsen-Johansson syndrome: This is an inflammation of bone at the inferior pole of the patella, typically in children, attributed to overuse injuries. **Ewing's sarcoma: This is a primary bone cancer that primarily effects children and adolescents. It is the 2nd most common bone cancer in children.

In the thoracic spine, just like in the lumbar spine, the Winking Owl sign can be an indication of serious spinal pathology. Which vertebral structure has the lytic lesion associated with this sign? - Facet - Spinous process - Pedicle

Pedicle Correct, this is a common site of a lytic spinal lesion which is eroded causing the winking owl sign.

A 42-year-old male, right-hand dominant, presents to you in your clinic with a 2-day​ history of right radial wrist pain. He's a carpenter by trade and fell off a short ladder, but broke his fall with his right hand. He's unable to hold his hammer or lift objects with his right hand secondary to pain. Self-treatment with ice and NSAID did make it feel a bit better until he tried to use it again. His pain is reproduced with palpation to the anatomic snuff box, and the scaphoid tubercle, he also has pain reproduction with 1st metacarpal compression. Based on his history and exam, what is the most appropriate recommendation for imaging? - No imaging recommended. - Plain X-ray imaging for the wrist. - MRI is recommended immediately to best evaluate scapholunate ligament tear - CT scan of the wrist

Plain X-ray imaging for the wrist. Correct answer. Consistent with history and the 3 physical exam findings. *Although CT scan is sensitive and specific for a suspected scaphoid fracture, they are not to be ordered as initial imaging modality.

A 22-year-old female college distance runner has an insidious onset of right hip pain. She denies any specific trauma but reports marked increase in distance running trying to get ready for the competitive season. Her pain increases with weight bearing activities and decreases with rest. She complains of pain now just with normal walking and you notice an antalgic gait. Based on this limited history you are suspecting a possible femoral neck stress fracture. You are recommending imaging to rule this out. Which imaging modality is most appropriate at this time? - Bone scan - MRI - CT scan - Plain hip radiographs

Plain hip radiographs Correct answer. Although occult fracture may occur, plain hip imaging is considered the first imaging of choice for this patient.

Which radiographic view of the shoulder allows for viewing of suspected shoulder dislocations and scapular fractures? - True AP view - AP with Internal rotation view - Scapular Y view

Scapular Y view Correct, this is the best view for dislocation consideration as it shows the AP position of the humerus in relationship to the glenoid.

__________ is produced by deflection of some of the primary x-ray beam. A grid is used to reduce this effect during imaging. - Body size - Distortion - Scatter

Scatter Correct, in order to limit scatter, a grid is used within the system to block the bouncing -or scatter- of the particles.

The Canadian C-Spine Rules is a highly sensitive screening tool for patients that have had cervical trauma and who may need imaging. The first series of question to ask your patient is in regarding high risk factors. Which of the following is not considered a high risk factor? - Age ≥ 65 years - Paresthesias into the extremities - Simple rear end bump/shunt (5 mph or less)

Simple rear end bump/shunt (5 mph or less) Correct, according to the rules, this is not considered a high risk factor.

Which x-ray view would you order if you wanted the best view of the patellofemoral joint? - Tunnel view - AP view - Sunrise view

Sunrise view Correct, this is the best view if you are looking for specific pathology of the patella or patellofemoral joint.

The Ottawa ankle rules tells you that X-rays are required if there is acute trauma with pain in the malleolar zone and either inability to walk 4 steps, or: - Tenderness posterior and tip of med/lat malleolus - Ankle effusion - Calcaneal tenderness

Tenderness posterior and tip of med/lat malleolus Correct, these clinical signs are highly sensitive signs that your patient needs imaging of the injured ankle.

Which of the following statements is FALSE regarding pelvic fractures? - With pelvic trauma - AP view is usually sufficient. CT scan is second line study. - Widening of the symphysis pubis > 1 cm is abnormal. - The pelvis is a ring and fractures usually occur in only one area.

The pelvis is a ring and fractures usually occur in only one area. Correct, bony rings rarely fractures in only one location, if one fracture is seen on imaging, there is a high correlation for 1 or more other fractures.

True or false: Bone scans are more sensitive than plain radiographs for early detection of femoral neck stress fractures. - True - False

True Correct, the bone scan can detect an femoral neck stress fracture when the plain film is normal.

According to the Ottawa knee rules for acute trauma, you would order knee X-rays if your patient had acute trauma with either palpable tenderness over the fibular head or patella, or is ≥ 55 years of age, or unable to weight bear 4 steps, or: - Unable to flex knee > 90º - Has knee effusion - Ecchymosis anywhere around the knee

Unable to flex knee > 90º Correct, this is a criteria of the Ottawa knee rules, which are guidelines to aid emergency physicians in deciding when to use imaging in patients with acute trauma to the knee. Inability to flex the knee >90 º can be indicative of a condition that warrants x-ray imaging to confirm, such as a fracture or dislocation.

T2 weighted MRI are better than T1 for showing contrasting normal and abnormal tissue. On T2 images, water and CSF appear as what color on MRI? - White (or bright) - Black - Dark

White (or bright) Correct, on T2 images water is white, therefore CSF is white due to T1's high water content.

You believe your patient is complaining of hip pain consistent with hip osteoarthritis, for which you order hip radiographs. Which of the following is not a hallmark radiographic feature of OA? - Osteophyte formation (bone spurs) - Widening of the joint space - Subchondral bone cysts

Widening of the joint space Correct, the opposite is true, Joint space narrowing is one of the hallmark radiographic features of OA.

You are considering whether or not to order an X-ray on a 40-year-old female patient whom you are seeing in the clinic following an accident over the weekend where she was a passenger in a car and they hit a cement block while parking the car. He said they were traveling less than 2 miles an hour when it occurred. You have used the C-Spine rules and are assessing cervical ROM. You note 85 degrees of rotation to the right and 30 degrees of rotation to the left. Based on this scenario, would you order C-spine imaging according to the Canadian C-spine rules? - Yes - No

Yes Correct answer. Although it was not a high risk injury, the fact that the patient cannot rotate greater than 45 degrees in both directions suggests that this patient requires imaging

You are providing medical coverage for a softball tournament when a 50-year-old female reports to your station immediately following an injury to her shoulder after "landing wrong" on her arm and shoulder. She's uncertain of the exact mechanism as it happened so quickly. She is cradling her arm in a splinted position and reporting 9/10 pain. She claims she has never hurt this shoulder before now. Upon observation you can tell that the glenohumeral joint has lost its normal contours and has the appearance of a dislocation. She has neurovascular intact distally, with diminished sensation over the deltoid region. Based on this history and limited exam, prior to reduction, does she require imaging according to the Quebec decision rules by Edmonds, et al? - Yes - No

Yes Correct answer. Since she is over 40 years old and this her first incidence of dislocation, imaging is recommended prior to reduction

You are evaluating a 27-year-old male following a right knee injury he sustained in a rec-league football game 4 days ago. He is ambulating non-weight bearing with crutches, which he had from a previous ankle injury, because of pain with weight-bearing and swelling. He has tried to stop using the crutches but he can't fully weight bear due to pain. He said the swelling reduced from a couple of days ago. He asks you what he should do next as he is concerned about causing further damage. He asks if he needs imaging at this point. On exam he's unable to flex past 60 degrees, is tender at the patella and joint line and can't weight bear without crutches. Do you send him for imaging and if so, which imaging modality do you order initially? - No imaging necessary at this point - Yes, order plain X-rays of the knee - Yes, order MRI - Yes, order a CT scan to rule out ligamentous injury as well

Yes, order plain X-rays of the knee Correct answer. Based on the Ottawa knee rules he fits the criteria for ordering plain X-ray imaging for the knee.

Not all patients with shoulder dislocations require pre-reduction imaging. According to the Emond et al study, which of these patients would not require pre-reduction imaging? - Aged 40 years or older and humeral ecchymosis - Aged 40 years or older and first episode of dislocation - Younger than 40 years and multiple prior dislocations

Younger than 40 years and multiple prior dislocations Correct, this age group require pre-reduction imaging only if it was their first time dislocating.

If you wanted to get the best radiographic view of the AC joint with plain X-ray, which image would you order? - Zanca view - West Point view - Stryker notch view

Zanca view Correct, the Zanca view is an AP projection with a tilt directing the beam through the AC joint.

On plain X-ray of the elbow, the radial head should always line up with what other structure on both the AP and the lateral view? - coronoid process - olecranon process - capitulum

capitulum Correct, when viewing both the lateral and AP view of the elbow, you should always evaluate the alignment of the radial head in relation to the capitulum.

It has been reported that up to 40% of radiology reports have been read incorrectly. One reason for the incorrect readings is due to incomplete or faulty search patterns. This is known as: - errors of observation - errors of interpretation - errors of judgment

errors of observation Incomplete or faulty search patterns can lead to observation errors.

A simple clinical test can identify patients with elbow injuries who require plain X-ray imaging to rule out a fracture, what is it? - full active elbow extension - full active elbow flexion - full active elbow pronation/supination

full active elbow extension Correct, the elbow extension test has been shown in clinical studies to be a sensitive test for patient with acute elbow injuries requiring imaging.

The ossification sequence of the elbow is fairly predictable. What is the last structure in the elbow to ossify or fuse? - capitulum - radial head - lateral epicondyle

lateral epicondyle Correct, the lateral, or "external" epicondyle, it makes up the "e" in the eponym "critoe" making it the last site of ossification for the elbow.

Duckworth et al developed a CPR for evaluation of scaphoid fractures. This CPR will help determine if your patient requires imaging. The four variables are 1) injured in sporting activity, 2) male gender, 3) snuff box pain within 72 hours, and: - tenderness with palpation of the lunate - tenderness to palpate scaphoid tubercle - Watson's test

tenderness to palpate scaphoid tubercle Correct, palpation of the scaphoid tubercle is an important part of the evaluation for scaphoid fractures.