Introduction to Diagnostic Imaging

All radiographs need...

a marker for whether it is a PA, if it is a R or L limb, or what type of view is being completed

Single contrast barium enema

a method of imaging the colon with fluoroscopy and is similar in concept to the double contrast barium enema. "Single contrast" refers to imaging with barium or water-soluble contrast only, without addition of air or CO2. not used as often since CT can be more helpful for and an easier tool for assessment.

Standard of the knee series for XR

is a set of two x-rays of the knee joint (lateral view and AP view, can have sunrise view of the patella). It is performed to look for evidence of injury (or pathology) affecting the knee, often after trauma

Fat densities on a radio graph

is just a shade or two lighter than gas, a dark gray, and becomes important in specific locations

Images of CT pulmonary angiography in pt. with PE or a large aortic aneurysm

axial view is also a a transverse plane view (this image is two different PEs) the sagittal plane cut (mediolateral view in the aortic aneurysm present)

Antero-posterior (AP) x-ray projection

central ray passes from anterior to posterior

posterio-anterior (PA) x-ray projection

central ray passes from posterior to anterior

A CT scan machine

combines a series of X-ray images taken from different angles around your body and uses computer processing to create cross-sectional images (slices) of the bones, blood vessels and soft tissues inside your body in all three planes necessary. CT scan images provide more-detailed information than plain X-rays do. image shows the machine and an example of a CT can be given IV contrast, oral contrast, or no contrast if the patients are allergic to the dye then the patient will be given a radio isotope instead

The pelvis series for XR

comprised of an anteroposterior (AP) (this is the standard method with additional projections based on indications and pathology. The series is used most in emergency departments during the evaluation of multi-trauma patients due to the complex anatomy the AP projection covers The female inlet is larger and oval in shape, while the male sacral promontory projects further (i.e. the male inlet is more heart-shaped). ... The greater sciatic notch is wider in females. The iliac crests are higher and more pronounced in males, making the male false pelvis deeper and more narrow than in females.

Lumbar spine series radiographs

comprised of two standard projections along with a range of additional projections depending on clinical indications. The series is often utilized in the context of trauma, postoperative imaging and for chronic conditions. Standard projections •PA/AP view •the entire lumbar spine should be visible, with a demonstration of T11/T12 superiorly and the sacrum inferiorly •often performed erect unless otherwise indicated •lateral view •visualization of lumbar vertebral bodies, pedicles, and facet joints •ideal projection when examining for suspected fractures •can be performed erect to assess stable fracture (under a specialist's guidance)

Dark on T1-weighted image of MRI

increased water, as in edema, tumor, infarction, inflammation, infection, hemorrhage (hyperacute or chronic) low proton density, calcification flow void

Bright on T2-weighted image MRI

increased water, as in edema, tumor, infarction, inflammation, infection, subdural collection methemoglobin (extracellular) in subacute hemorrhage

Summary of the information received from a pelvis XR

indications hip trauma trauma with leg length discrepancy assessment of unilateral hip pain follow up in unilateral hip pathology procedure AP radiograph, of the pelvis second view of the hip shoot through lateral with the good leg flexed oblique view similar tests pelvis x-ray just the pelvis x-ray used for general pelvis assessment, e.g. trauma important pathology pelvic fracture proximal femoral fracture

MR direct arthrogram

involves the injection of a contrast material into the joint. The contrast material (gadolinium) used for MR evaluation is different from that used for x-ray; it contains gadolinium, which affects the local magnetic field within the joint and appears on the MR images. As in conventional direct arthrography, the contrast material outlines the structures within the joint, such as cartilage, ligaments and bones, and allows them to be evaluated by the radiologist after the MR images are produced.

Cervical spine radiographs series

is a set of radiographs taken to investigate the bony structures of the cervical spine, albeit commonly replaced by the CT, the cervical spine series is an essential trauma radiograph (the CT are easier to visualize these structures) first one is to assess a lateral C/S XR to determine the current set up the markers indicate that the side of the body closest to the image capturing film standard projections: AP anteroposterior projection of the cervical spine demonstrating the vertebral bodies and intervertebral spaces lateral often utilized in trauma demonstrated zygapophyseal joints soft tissue structures around the c spine spinous processes anterior-posterior relationship of the vertebral bodies odontoid also known as a 'peg' projection it demonstrates the C1 (atlas) and C2 (axis) AP oblique demonstrates the intervertebral foramina of the side positioned further from the image receptor PA oblique demonstrated the intervertebral foramina of the side positioned closer to the image receptor

Dark on T2-weighted image MRI

low proton density, calcification, fibrous tissue paramagnetic substances: deoxyhemoglobin, methemoglobin (intracellular), iron, ferritin, hemosiderin, melanin protein-rich fluid flow void

contrast media

such as barium, iodine, and air are used to visualize internal organs as they work.

Catheter angiography

uses a catheter, x-ray imaging guidance and an injection of contrast material to examine blood vessels in key areas of the body for abnormalities such as aneurysms and disease such as atherosclerosis (plaque). The use of a catheter makes it possible to combine diagnosis and treatment in a single procedure. Catheter angiography produces very detailed, clear and accurate pictures of the blood vessels and may eliminate the need for surgery.

Cerebral angiography

uses digital subtraction angiogram)- to check the blood vessels in and around the brain

Nuclear medicine

uses small amounts of radioactive tracers called radiopharmaceuticals that are typically injected into the bloodstream, inhaled or swallowed (can be done for different types of internal structures). The radiotracer travels through the area being examined and gives off energy in the form of gamma rays which are detected by a special camera and a computer to create images of the inside of your body. How the process of image works: A gamma camera, also called a scintillation camera, is a device used to image gamma radiation emitting radioisotopes, a technique known as scintigraphy. Single Photon Emission Computed Tomography or SPECT and Positron Emission Tomography or PET scans are the two most common imaging modalities in nuclear medicine image is Example of SPECT imaging heart scan Planar liver/spleen scan

Direct CT arthrogram

uses the same type of contrast material as conventional direct arthrography and may be supplemented by air to produce a double contrast CT arthrogram. CT makes cross sectional images processed by a computer using x-rays

Bright on T1-weighted image for MRI

-fat -subacute hemorrhage -melanin -protein-rich fluid -slowly flowing blood -paramagnetic substances: gadolinium, manganese, copper calcification (rarely) -laminar necrosis of cerebral infarction

different methods for performing angiography

-x-rays with catheters -computed tomography (CT) -magnetic resonance imaging (MRI)

Ottawa knee rules

A knee x-ray series is only required for knee injury patients with any of these findings: §Age 55 or older. §OR. §Isolated tenderness of the patella. §No bone tenderness of knee other than patella. §OR. §Tenderness of the head of the fibula. §OR. §Cannot flex to 90 degrees. only one of these needs to be present for determining the need for an XR of the knee

Nuclear medicine for treatment of pulmonary embolism

A lung scan can be a ventilation scan or a perfusion scan. A ventilation scan looks at how air moves in and out of your lungs. Decreased uptake of the inhaled radioisotope may indicate an impaired ability to breathe, airway obstruction, or possible pneumonia. Decreased circulation of the injected MAA indicates a problem with blood flow into or within the lungs. A localized area of decreased uptake, usually in a wedge shaped (or pie shaped) configuration with normal ventilation images (mismatched defect) suggests a pulmonary embolus or blood clot in the lungs, which leads to reduced perfusion beyond the obstruction.

Scans option according to body part (CT vs. MRI)

Abdominal Pain - In cases of abdominal pain, the preferred test is considered to be a CT scan. It is easily accessible for emergencies and has a high accuracy rate. Ultrasound scans are usually used for children and pregnant women. Trauma - Most emergency departments have a CT scan machine on hand and it is the best option to see any bone trauma or blood and organ injury. Spine - MRI imaging is considered to be the best option for creating images of the spinal cord and nerves. Brain - CT scans are used when speed is of primary importance. This is most often the case for trauma or strokes. MRI is best used when there needs to be a detailed image in case the doctor is looking for cancer, causes of dementia, neurological diseases, or if the doctor is looking for a place where the bone might be interfering. Chest - CT scans are the most effective when one needs to examine lung tissue and are often used to follow up on abnormal chest x-rays. Low dose CT scans are also available for high-risk smokers who need to be scanned annually. Joints - MRI is the best scan for joints, tendons, and ligaments.

Nuclear medicine for osteomyelitis

Comparison of pre- and posttreatment 68Ga-citrate PET/CT scans in patient with acute osteomyelitis. Pretreatment scan showed increased radiotracer uptake involving proximal tibia. Posttreatment scan showed no significant uptake, representing complete response to treatment. Antibiotics help bring the infection under control and often make it possible to avoid surgery. People with osteomyelitis usually get antibiotics for several weeks through an IV, and then switch to a pill. More serious or chronic osteomyelitis requires surgery to remove the infected tissue and bone.

Cardiac silhouette on chest XR

On an antero-posterior (AP) or postero-anterior (PA) view of the chest, the borders of the heart have common landmarks: Right Border: Formed by the right atrium which is in between the SVC and IVC Left Border: Formed by the left ventricle & portion of the left auricle Anterior Surface or Sternocostal Surface: Mainly the right ventricle (not seen on AP view) Inferior Border: Combination of the right & left ventricles

Procedure for different joints with arthrography

Shoulder - AP shoulder with the patient's arm in a neutral position. There is is adequate double-contrast outlining of the shoulder joint. The subacromial space is well demonstrated. Elbow - Typically the radiocapitellar joint is punctured from lateral with the patient prone and the arm flexed 90 degrees overhead (red arrow).This however can sometimes cause problems if you are interested in the lateral ligaments and you inject lidocaine or contrast into these ligaments.So more recently we started to use the posterior approach into the olecranon fossa (blue arrow). Diluted gadolinium is injected, i.e. 0,05cc + 10cc saline (an "off-label" use in the US). Wrist - normal Hip - Fluoroscopic spot image during the joint-injection step of MR arthrography demonstrates a small amount of iodinated contrast (arrow) confirming intraarticular positioning Ankle - Anteroposterior (A) view of an ankle arthrogram demonstrating an anterior talofibular ligament tear with contrast extravasation (arrowhead) but no filling of the peroneal tendon sheaths.

Standard PA chest XR

Standard projections •PA view •is performed standing and in full inspiration (helps to expand the lungs) •it examines the lungs, bony thoracic cavity, mediastinum and great vessels •disadvantages: must be able to stand erect •advantages: better visualization of the mediastinum and lungs

Standard sequences for the MRI imaging types

T1, T2, - time (relaxation time) FLAIR, - Fluid-attenuated inversion recovery (FLAIR) is an MRI sequence with an inversion recovery set to null fluids. For example, it can be used in brain imaging to suppress cerebrospinal fluid (CSF) effects on the image, so as to bring out the periventricular hyperintense lesions, such as multiple sclerosis (MS) plaques. STIR, - STIR stands for Short-TI Inversion Recovery and is typically used to null the signal from fat PDfs, - Proton density (PD) image characteristics. When an MRIsequence is set to produce a PD-weighted image, it is thetissues with the higher concentration or density of protons (hydrogen atoms) which produce the strongest signals and appear the brightest on the image. DWI, - Diffusion-weighted imaging (DWI) is a form of MR imaging based upon measuring the random Brownian motion of water molecules within a voxel of tissue. In general simplified terms, highly cellular tissues or those with cellular swelling exhibit lower diffusion coefficients. SWI - Susceptibility weighted imaging (SWI), originally called BOLD venographic imaging, is an MRI sequence that is exquisitely sensitive to venous blood, hemorrhage and iron storage. SWI uses a fully flow compensated, long echo, gradient recalled echo (GRE) pulse sequence to acquire images

Gadolinium

T1-weighted imaging can also be performed while infusing Gadolinium (Gad). Gad is a non-toxic paramagnetic contrast enhancement agent. When injected during the scan, Gad changes signal intensities by shortening T1 resonance reception signal. Gad is very bright on T1-weighted images. Gad enhanced images are especially useful in looking at vascular structures and breakdown in the blood-brain barrier [e.g., tumors, abscesses, inflammation (herpes simplex encephalitis, multiple sclerosis, etc.)].

The radiographs series of the hand and carpals

The PA, OBL, and LAT views are part of a three view series examining the phalanges, metacarpals and carpal bones that make up the hand and wrist.

Practical points for the foot radiographs

The bases of the metatarsals and the tarsal bones are the most reliable rotation indicator on the DP view. If the foot is over rotated externally, the metatarsal bases will be heavily superimposed whilst the tuberosity of the navicular bone can be seen in profile. Over rotation internally will open up the metatarsal bases and the resultant image will bear close resemblance to the medial oblique projection. In the scenario where the DP is ordered to query a foreign body, do not angle the x-ray beam to mimic the arch as this will result in elongation of the foreign body in question. In trauma, the patient may not be able to flex the affected knee to the desired angle. In this case, a triangular wedge can be placed under the foot. The same principle of angling posteriorly to mimic arch applies. With the foot resting at 10-15° less of an angle is required.

Image technical evaluation (normals) for the ankle and foot radiographs

The distal fibula should be slightly superimposed over the distal tibia. The lateral and medial malleoli of the distal fibula and tibia are in profile. The tibiotalar joint space should be open, yet the full mortise joint should not be visualized on the AP.

The radiographs for the foot

The dorsoplantar view is part of a three view series examining the phalanges, metatarsals and tarsal bones that make up the foot

Conventional direct arthrography

This done for a §joint often uses a special form of x-ray called fluoroscopy to guide and evaluate the injection of iodine contrast material directly into the joint. §Today's trend - Alternate methods of direct arthrography examinations use magnetic resonance imaging (MRI) or computed tomography (CT) following contrast material injection into the joint.

The spectrum for x-rays

X-rays are part of the electromagnetic spectrum, with wavelengths shorter than visible light. Different applications use different parts of the X-ray spectrum

Image technical evaluation of lateral chest x-ray

The entire lung fields should be visible superior from the apices inferior to the posterior costophrenic angle the chin should not be superimposing any structures there is superimposition of the anterior ribs the sternum is seen in profile superimposition of the posterior costophrenic recess a minimum of ten posterior ribs are visualized above the diaphragm the ribs and thoracic cage are seen only faintly over the heart clear vascular markings of the lungs should be visible some practical points The left lateral is the preferred lateral position as it demonstrates better anatomical detail of the heart. The same principle of positioning can be applied to patients in a chair. Before exposing ensure your patient is not leaning forward or backward too much, this will result in anatomy being cut off. Patients with a longstanding history of emphysema or COPD will have abnormally long lungs compared to the general population, remember this when collimating superior to inferior. Side marker placement is imperative; patients can have congenital conditions that mimic a mirrored image 2. Patients with scoliosis may not demonstrate the traditional indicators of a correctly positioned lateral radiograph; it is important to note that patients with this condition particularly in the thoracic region will appear rotated by conventional evaluation, yet this is not the case. Remember to explain to your patient what you are about to do; that is, ask them to take a breath in and hold it. Many times this gives the patient time to prepare and results in a better breath hold and therefore a higher quality radiograph.

Clavicles on a chest XR

The head of the clavicle is attached to the lateral surface of the sternum. The location of the clavicular heads in relation to the trachea can help determine proper positioning of the patient at the time the chest radiograph was taken. The two clavicular heads should be on either side of the trachea and with the spinous processes being in the middle.

Hemidiaphragms on a chest XR

The right hemidiaphragm normally sits slightly higher than the left due to the presence of the liver under the diaphragm which prevents the right hemidiaphragm from going down further with inspiration. Important clinical pearls include: Each dome of the diaphragm is innervated by its own nerve supply from the phrenic nerve. Therefore, damage to the nerves for one side will not affect the other. On chest radiograph you would see the the paralyzed hemidiaphragm as being higher than the other hemidiaphragm during inspiration (creating a paradoxical pattern of movement with respiration). You should also not see free air under the hemidiaphragm. If free air is found you will see a black line under the hemidiaphragm which would be concerning for a bowel perforation. This requires emergent evaluation with a CT scan and surgical consult. Do not confuse the normal gastric bubble seem on many chest radiographs with free air.

Trachea on a chest XR

The trachea should sit midline and be in between the right and left clavicular heads. Any deviation from the midline could suggest that the patient was either rotated at the time of the chest radiograph, the presence of a mediastinal mass, or presence of a tension pneumothorax.

T2-weighted image MRI

There are multiple types of MRI based on if the image is captured at a different decay of signal. . A T2 weighted MRI captures the late stage of signal decay, or after a small amount of proton migration from the original resonance

T1 weighted MRI images

There are multiple types of MRI based on if the image is captured at a different decay of signal. A T1 weighted MRI captures early signal decay, that is, early after the protons are positioned

The canadian C/S rules (CCR) national emergency XR

These criteria are two clinical decision rules developed to help clinicians risk‐stratify patients with cervical spine trauma to determine if they need imaging to rule out clinically important CSI

The four densities on a radiograph

They are from black to white: gas, fat, water and mineral

The thoracic spine radiographs

This forms the middle part of the vertebral column. It extends from below C7 on the cervical spine to above L1 on the lumbar spine. There are 12 thoracic vertebra, termed T1-T12. The thoracic spine is unique due to its articulation with ribs via costal facets. The ribs restrict the movement of the thoracic spine somewhat. The thoracic spine is otherwise the most mobile of all spinal column segments. Patient position •the patient is erect •ideally, spinal imaging should be taken erect in the setting of non-trauma to give a functional overview of the thoracic spine •the lateral projection requires the upper limbs to be removed from the path of the direct x-ray beam, minimizing the superimposition of the proximal humeri over the thoracic vertebrae image shows a lateral view

practical points for the ankle radiographs

This view can be thought of as the literal anteroposterior of the ankle. Most patients will naturally place their foot in this position. Although dorsiflexion is essential in both the AP and the mortise view it should be noted that during trauma this may not be possible. The talus is a tarsal bone in the hindfoot that articulates with the tibia, fibula, calcaneus, and navicular bones. It has no muscular attachments and around 60% of its surface is covered by articular cartilage. Lateral malleolus Laterally, it is continuous with the triangular area of the shaft and has a convex surface. Medially, its triangular facet articulates with the talus, and it has a rough area just above this facet. Plain radiograph It is important to understand the 3-dimensional orientation of the lateral malleolus within the ankle. The lateral malleolus is longer, larger and more posterior than the medial malleolus. Hence on a true lateral radiograph of the ankle, it is posterior to the medial malleolus. .

MRI (magnetic resonance imaging)

a non-invasive imaging technology that produces three dimensional detailed anatomical images. MRI uses a strong magnetic field and radio waves to create detailed images of the organs and tissues within the body. When you lie inside an MRI machine, the magnetic field temporarily realigns hydrogen atoms in your body there is no x-ray or ionizing radiation a magnetic field that realigns the hydrogen atoms in the body to create an image the hydrogen has a high magnetic moment that helps to create a photon that helps to capture the hydrogen molecules that is a accurate representation of the region being scanned The magnetic field created by the magnets causes resonance from each proton in the hydrogen atom and the machine is able to obtain the proton's position. Since approximately 75% of our bodies are made of water molecules, MR imaging is able to capture precise and detailed images of the viewed body region. Thus, the MRI takes a detailed "picture" of all hydrogen molecules in the body and is computed into an accurate representation of that body region. This technique is used to identify ligament and tendon injuries, spinal cord injuries, brain tumors, etc. MRI scanners use very strong magnets and may cause safety issues if there are metal objects around it when it is functioning. If a patient has aneurism clips in the brain they should not be prescribed MRI scans, unless these clips are MRI safe. If these clips are pulled out because of the MRI strong magnetic field the patient can bleed into the brain. MRI scans are also not advisable for patients with pacemakers or defibrillators because MRI scanners can cause disruption of battery operated devices. Metal should not be brought anywhere close to an MRI scanner. The strong magnetic field it creates can cause injuries and leave a patient in a worse state than what they have been brought in with causes pain or damage from the magnetic field

PET-CT scan

a nuclear medicine technique which combines, in a single gantry a positron emission tomography (PET) scanner and an x-ray computed tomography (CT) scanner, to acquire sequential images from both devices in the same session, which are combined into a single superimposed (co-registered) image Fluorodeoxyglucose F18 is the radioactive compound injected intravenously (if the patient has a high blood sugar this radioactive compound will not work) this is considered a fusion image that combines the nuclear medicine with the x-ray image put together Such imaging can differentiate people with Alzheimer's disease (AD) from those with other dementias. Alzheimer's disease, frontotemporal dementia (FTD), multi-infarct dementia, progressive supranuclear palsy, Huntington's disease, Parkinson's disease dementia, olivopontocerebellar atrophy, dementia with Lewy bodies, and Creutzfeldt-Jakob disease can have distinct PET-CT findings allowing early diagnosis. For instance, AD typically demonstrates hypometabolism within a temporoparietal distribution, while FTD demonstrates hypometabolism within the frontal lobes and anterior temporal lobes.

Merchant view of the knee

a superior-inferior projection of the patella. It is one of many different methods to obtain an axial projection of the patella. This is an ideal projection for patients that are better suited to the supine position. also considered the sunrise view as well and is taken in knee flexion

pulmonary angiogram images, using the subtraction technique

a test to see how blood flows through the lung. Angiography is an imaging test that uses x-rays and a special dye to see inside the arteries. Normal R Pulmonary artery angiogram Pulmonary angiogram in a patient with PE. The clot appears as a filling defect (arrow) seen in images

Magnetic resonance angiogram (MRA)

a type of magnetic resonance imaging (MRI) scan that uses a magnetic field and pulses of radio wave energy to provide pictures of blood vessels inside the body. A standard MRI cannot provide a good picture of the blood vessels and blood flow used to generate images of arteries in order to evaluate them for stenosis, occlusions, aneurysms or other abnormalities.

diagnostic radiology

designates the technical aspects of medical imaging and in particular the acquisition of medical images. Two forms of radiographic images are in use in medical imaging. Projection radiography and fluoroscopy, with the latter being useful for catheter guidance. These 2D techniques are still in wide use despite the advance of 3D tomography due to the low cost, high resolution, and depending on the application, lower radiation dosages with 2D technique. This imaging modality utilizes a wide beam of x rays for image acquisition and is the first imaging technique available in modern medicine.

The shoulder series for radiographs

fundamentally composed of two orthogonal views of the glenohumeral joint including the entire scapula. The extension of the shoulder series depends on the radiography department protocols and the clinical indications for imaging. Standard projections •AP view •demonstrates the glenohumeral joint in the natural anatomical position •shows the humeral head superimposing the glenoid of the scapula •displays the entire clavicle, AC joint, scapula, superior ribs, SC joint and proximal humerus •lateral or scapular Y view •orthogonal view of the AP shoulder view •profile view of the scapula •demonstrates the degree and direction of any suspected dislocations

What are CT scans in general?

has many uses, but it's particularly well-suited to quickly examine people who may have internal injuries from car accidents or other types of trauma. A CT scan can be used to visualize nearly all parts of the body and is used to diagnose disease or injury as well as to plan medical, surgical or radiation treatment. In certain cases a contrast material is used: •injected through a vein in the patient's arm •asked to drink before the CT scan (similar to a barium swallow test) Although rare, the contrast material can cause medical problems or allergic reactions (alternative methods used instead if that is the case) if patient is allergic to shellfish this is something to be asked about

projectional radiographs

more commonly known as x-rays, are often used to determine the type and extent of a fracture as well as for detecting pathological changes in the lungs. With the use of radio-opaque contrast media, such as barium, they can also be used to visualize the structure of the stomach and intestines - this can help diagnose ulcers or certain types of colon cancer.

CT angiography

no catheter used a test that uses X-rays to provide detailed pictures of the heart and the blood vessels that go to the heart, lung, brain, kidneys, head, neck, legs, and arms. A CT angiogram can show narrowed or blocked areas of a blood vessel there is a injection of dye sent in to get a solid visual of the blood vessels (quick study)

Ankle series parts for visualizing these structures

part of a three view series of the distal tibia, distal fibula, proximal talus and proximal metatarsals The standard ankle series is comprised of the (from left to right): •1.AP projection •2. mortise projection •3. lateral projection

Barium swallow/upper GI series

physicians will look for a normal small bowel meal demonstrates the rugal folds in the stomach and the valvulae conniventes the small bowel. physician can visualize as the patient swallows, and examine for obstruction, hiatal hernias, looking at EG junction, it is a real time process for assessment

Indications for shoulder XRs

shoulder trauma bony tenderness at the glenohumeral joint/region restriction of rotation instability suspected dislocation AC joint injury scapula trauma suspected arthritis non-traumatic shoulder pain

PET scan

positron emission tomography an imaging test that helps reveal how your tissues and organs are functioning. A PET scan uses a radioactive drug (tracer) to show this activity. This scan can sometimes detect disease before it shows up on other imaging tests. gives off some radiation that may decay after a certain amount of time, excreted through the kidneys when it is injected

fluoroscopy

produces real-time images of internal structures of the body in a similar fashion to radiography, but employs a constant input of x-rays, at a lower dose rate. Computers help create images of the structures while oral contrast is used to enhance these images. used to help diagnosis problems with your esophagus, stomach, duodenum and small bowels. This procedure allows doctors to visualize the movement of oral contrast through the digestive system in real time. also used in image-guided procedures when constant feedback during a procedure is required

PET scans for Alzheimer's disease

see image the red and hot structures point toward structures that are damaged and affected creating AD do not want to give a dx for AD until we know for sure this is what the patient is experiencing based on the imaging techniques used

the use of digital subtraction angiogram for cerebral angiography

see image used to evaluate the presence of abnormalities in the blood vessels in of the head and neck prior to surgery Physicians use the procedure to detect or confirm abnormalities within the blood vessels in the brain, including: an aneurysm, a bulge or sac that develops in an artery due to weakness of the arterial wall. atherosclerosis, a narrowing of the arteries. arteriovenous malformation, a tangle of dilated blood vessels that disrupts normal blood flow in the brain. vasculitis, an inflammation of the blood vessels, generally narrowing them. a brain tumor. a blood clot. a tear in the wall of an artery, known as a vascular dissection. a stroke. A cerebral angiogram may be performed: to evaluate arteries of the head and neck before surgery. to provide additional information on abnormalities seen on MRI or CT of the head, such as the blood supply to a tumor. to prepare for other medical treatment, such as in the surgical removal of a tumor. in preparation for minimally invasive treatment of a vessel abnormality. The procedure may also be used to help diagnose the cause of symptoms, such as: severe headaches slurred speech dizziness blurred or double vision weakness or numbness loss of coordination or balance. the catheter is probed into the femoral artery in the leg and is passed all the way up into the internal carotid artery to image it and assess it like in the image

CT for trauma: indications and images

see images from top to bottom and left to right the pathologies are following: Bilateral Subdural hematomas Hemothorax post trauma Blunt Left kidney trauma Lumbar CT scan shows burst fracture after a fall The CT-images nicely display the fracture through the growth plate and the epiphysis.

The CT scans versus MRI scans

see images to examine the differences between these two scans

Costocardiac and costophrenic angles on chest XR

should be fairly sharp and well defined if the patient does not have significant effusions or pulmonary edema. If they are blunted or lost, you should be concerned for the presence of fluid in the lung or a mass obstructing the view. Additional imaging with a chest CT may sometimes be warranted if the etiology is not clear from the patient's presentation.

Aortic knob

should be visualized in the normal chest radiograph around the level of T3 to T4 or just lateral to the carina. In patients with aortic aneurysm, this can be the area contributing to the "widened mediastinum".

Nuclear medicine: planar imaging

the acquisition of 2D nuclear images, similar to plain films in x-ray imaging. Static Used for studies in which the distribution of the radiopharmaceutical is effectively static throughout the acquisition e.g. bone scan Inject → wait → image The time from injection to imaging depends on the study being performed. The total time of imaging can be determined by a preset time or a preset number of counts A static image can provide information on: Organ size, shape and position Regions of increased or decreased uptake Examples: DMSA renal scan, bone scan, lung perfusion scan Dynamic Used for studies in which the distribution of the radiopharmaceutical changes rapidly with time Inject → image immediately → acquire series of frames over time The time between frames varies depending on the study being performed A dynamic study provides information on: Variation of radiopharmaceutical distribution over time Examples: MAG3 renal scan, gallbladder emptying scan, gastric emptying scan Gated Used to study organs with regular physiological motion Example: cardiac gated blood pool imaging - acquisition is triggered by the R wave of the ECG. Images are then acquired. When the R wave occurs again the new images are overlaid onto the images from the previous cardiac cycle.

The elbow series for radiographs

the elbow has to be fully extended (hard when there is a lot of trauma and pain for the imaging) a set of radiographs taken to investigate elbow joint pathology, often in the context of trauma. It usually comprises an AP and lateral projection, although other non-standard, modified projections are utilized for specific indications. the standard is to complete elbow projections: AP view •demonstrates distal humerus, proximal ulna, and radius •shows both the medial and lateral epicondyles in profile Lateral view •best demonstrates the ulna-trochlear joint, coronoid process, and the olecranon process •used to assess both the anterior humeral line and the radiocapitellar line

The chest radiograph

the most universal radiological investigation, especially important during COVID different conditions that can be viewable with this technique: •respiratory disease •cardiac disease •hemoptysis •suspected pulmonary embolism •investigation of tuberculosis •pneumonia •pneumothorax •suspected metastasis •follow up of known disease to assess progress •chronic dyspnea •trauma •evaluation of symptoms that could relate to cardiovascular and gastrointestinal systems •thoracic disease processes •monitoring of patients in intensive care units •post-operative imaging •immigration screening check position of nasogastric tubes, endotracheal tubes, PICCs etc

Plain radiographs of ankle and foot needs

the plain radiographic investigation of the distal tibia and fibula, the tarsal bones and metatarsals. Radiographic examination of the foot and ankle are often requested together, however, there is a plethora of literature to aid in the correct request of x-ray examinations in this region including the Ottawa ankle rules

Carina on chest XR

the point or level at which the trachea divides into the right and left main bronchi. This is usually midline with the spinous process being behind it. The carina is also the location that is used by healthcare providers when assessing the proper position of an endotracheal tube (ET) after intubation. Typically, the tip of the ET tube should be 3-4 centimeters above the carina so that both lungs are properly oxygenated.

radiographic positioning terms

these are routinely used to describe the position of the patient or the structures provided in the impression of the x-ray; examples include anterior, posterior, medial inferior, distal, superficial, proximal, etc.

how chest x-rays are taken

these x-rays are taken in an PA fashion where the camera is behind the patient and the "film" is anterior in front of the patient can be done in an AP view when it is not appropriate for the patient to be erect and standing (such as in ER during unconscious situation)

pulmonary angiography

to check the blood vessels supplying the lungs, to especially check for PEs

oblique x-ray projections

§ central ray passes through the body/body part through a plane which is at an angle to the transverse plane/coronal plane is desired (like when a spondylolysis is assessed view plain film radiograph)

The Pittsburgh knee rules

§Are a clinical decision-making strategy for determining which patients require radiographic imaging for knee pain. §A patient with knee pain qualifies for a radiograph if: §fall or blunt trauma §<12 years old or >50 years old §inability to take four steps, regardless of age §The original formulation of the Pittsburgh knee rules stated 100% sensitivity and 79% specificity for detection of fracture. §The Pittsburgh knee rules are often thought of in the context of the Ottawa knee rules. Some believe the Pittsburgh knee rules offer increased specificity

Direct arthrography

§Arthrography-a type of medical imaging used to help evaluate and diagnose joint conditions and unexplained pain. §It is very effective at detecting disease within the ligaments, tendons and cartilage. §Direct arthrography - contrast material is injected into the joint. §Arthrography may use computed tomography (CT) scanning, magnetic resonance imaging (MRI) or fluoroscopy - a form of real-time x-ray a way to see the image of the region of the body during real time motion different joints that can get this done: •shoulder •elbow •wrist •hip •knee •ankle The procedure is often used to help diagnose persistent, unexplained joint pain or discomfort. In some cases, local anesthetic medications or steroids may be injected into the joint along with the contrast material. These medications may temporarily decrease joint-related pain or inflammation and provide physicians additional information about possible sources of pain.

Advantages of MRI

§Better visualization of tissues §Better distinction of abnormalities §Multi-Plane imaging §No radiation

The ottawa ankle rules

§Bone tenderness at the posterior edge or tip of the lateral malleolus (A) §Bone tenderness at the posterior edge or tip of the medial malleolus (B) §OR. §An inability to bear weight both immediately and in the emergency department for four steps.

Disadvantages of MRI

§Expensive §Extensive amount of time for accurate images §Movement artefact (image distortion, need the person to sit still for really long) §10% of patients can't tolerate due to claustrophobia[5]

Some common abbreviations used in MRI impression reports

§FS - Fat Suppressed §FATSAT - Fat Saturation §STIR - Short Inversion Recovery Time Imaging §FSE - Fast Spin Echo §Gad - Gadolinium

Mineral densities on a radiograph

§Mineral density is noted throughout bones of the skeleton §The really white appearance of metal, such as seen in an ingested foreign body like a ring.

Chest x-ray compentency for medical students

§Using A, B, C, D, E is a helpful and systematic method for chest x-ray review: §A: airways §B: breathing (the lungs and pleural spaces) §C: circulation (cardiomediastinal contour) §D: disability (bones - especially fractures) §E: Exposure and everything else, e.g. pneumoperitoneum

X-rays

§X-rays represent a form of electromagnetic radiation. They are produced by the x-ray tube, using the high voltage to accelerate the electrons produced by the cathode. The produced electrons interact with the anode, thus producing x-rays. §Patients having an x-ray are exposed to ionizing radiation Digital radiography is a form of radiography that uses x-ray-sensitive plates to directly capture data during the patient examination, immediately transferring it to a computer system without the use of an intermediate cassette. ... Instead of X-ray film, digital radiography uses a digital image capture device.

lateral x-ray projection

§central ray passes from one side of body to the other through the axial plane (going mediolateral)

Body positions used on x-ray impressions

§erect: either standing or sitting §decubitus: lying down §supine: lying on back §prone: lying face-down §lateral decubitus: lying on one side -§right lateral: right side touches the table -§left lateral: left side touches the table

The gas density on a radiograph

§includes air in the lungs and upper airway, and gas in the intestines. It becomes black on a radiograph because there are few molecules to stop or attenuate the x-ray beam as it passes through the body to darken the film.

Water densities on a radiograph

§makes up the majority of body parts and includes muscle and organs. Imaged here is the psoas muscle.

coronary angiography

§to check the heart and nearby blood vessels. The doctor may recommend that you have a this if you have: Symptoms of coronary artery disease, such as chest pain (angina) Pain in your chest, jaw, neck or arm that can't be explained by other tests New or increasing chest pain (unstable angina) A heart defect you were born with (congenital heart disease) Abnormal results on a noninvasive heart stress test Other blood vessel problems or a chest injury A heart valve problem that requires surgery

image technical evaluation (normals) for the foot radiographs

•1st metatarsal has even concavity •the spaces between the 2nd to 5th metatarsal are equal, yet the bases are overlapping •intertarsal space between the medial and intermediate cuneiform should be open

reasons CT scans are ordered

•Diagnose muscle and bone disorders, such as bone tumors and fractures (not the greatest at finding fractures) •Pinpoint the location of a tumor, infection or blood clot •Guide procedures such as surgery, biopsy and radiation therapy •Detect and monitor diseases and conditions such as cancer, heart disease, lung nodules and liver masses (assesses if the drug is actually working) •Monitor the effectiveness of certain treatments, such as cancer treatment -Detect internal injuries and internal bleeding

Standard projection for a lateral chest XR

•performed erect left lateral, labeled with the side closest to the cassette/chest board •ideal for localization of suspected lung lesions when taken in conjunction with the PA view •examines the retrosternal and retrocardiac spaces •used to confirm the presence & location of opacities on PA CXR •salient points •gastric bubble is under the left hemidiaphragm; left hemidiaphragm is less distinct due to the cardiac silhouette •right hemidiaphragm appears higher and more complete (as the right is closer to the beam)