X Ray Flashcards
Skull XR ABCD
A= Alignment and anatomy (do we line up?) B= Bony integrity (are the bones smooth?) C= Cartilage (is the joint space narrowed?) S= Soft tissues (is there soft tissue swelling?)
2 ways to reduce radiation exposure
- Shielding - Distance
The System
2 definitions (radiopaque, radiolucent) 3 rules (“BILL”) 1 acronym ( “I Quit And Wanna Be Free!”)
“I Quit And Wanna Be Free!”
Identify Quality Air shadows Water Shadows Bone shadows Funny-looking things
Bones
“Bones are smooth and when they are not smooth, they’re broken”
Fracture Rules
Are the bones smooth (breaks in the continuity of the cortex)? Are there radiolucent fracture lines (blood and fat in between the distracted bony fragments)? Are there abnormally white areas (overlap of cortical and trabecular bone “crushed” together)? Are there unexplained bony chips (fragments), even if a fracture isn’t visible? Are there dense areas due to the impaction of bone?
If you think that there was enough force generated upon the skull that you want to “rule out” a skull fracture,
GET A NON-CONTRAST HEAD CT SCAN!!!!!
Facial Fractures
Le Fort I (bad), II (worse), and III (terrible) (A PAeasy question ^)
Standard views are AP
lateral (to C7), odontoid, (if lateral is not to C7-get a swimmer’s view)
Radiologically Stable:
Clay-Shoveler’s Wedge Extension Teardrop
Radiologically Unstable:
Flexion Teardrop Hangman’s Burst Jefferson’s Odontoid
What views are included in an acute abdominal series?
Supine (KUB), upright, PA upright chest
describe the abdominal “tree”
When approaching an abdominal film, look for the tree: Trunk=spinal column, supported by the psoas muscles; pelvis is base; ribs=branches
what do you do if you suspect air in the abdomen but don’t see it on xray?
Order non-contrast Ab CT.
How does small bowel dilation look on xray?
Small bowel has stacked coin appearance, lines will be visible all the way across if dilated. Normal small bowel diameter is <3cm. Springs, tunnels, turtles (turtle shell appearance).
How does dilated large bowel look on xray?
Trapped fluid in dilated bowel may look like turtle shells. Large bowel does not have ‘stacked-coin’ appearance. Springs, tunnels, turtles.
How do abnormal water/fluid shadows look on abdominal xray?
Diffuse opacity. Psoas muscles will be obliterated. Air-fluid level on upright view and LL decubitus.
A foreign body appears flat at the level of the clavicles is likely in the esophagus or trachea?
Esophagus. FBs in trachea is 90 degrees turned, typically (edge of coin).
How does a AAA appear on abdominal Xray?
Egg-shell calcifications suggest atherosclerosis, esp on lateral view.
What does an “apple core” lesion in the large bowel on abdominal contrast xray suggest?
colon cancer.
In general, why order an abdominal CT?
Looking for non-intestinal abdominal pathology.
RIP acronym for quality of a chest xray
Rotation- check clavicles. Medial ends should be equidistant from midline. Inspiration- should be min 8 pairs of ribs visible, 2 above clavicles. Penetration- check interspaces, should be visible above clavicles. Thoracic vertebral bodies should NOT be well defined.
Where do you look for fluid in the pleural space on an AP chest film?
In the costophrenic angles (should be SHARP). Will be blunt if fluid. Cardiac border can be obliterated.
2 things to remember about radiologic enlargement of the heart: how is it defined? how is it interpreted?
Heart should be less than 1/2 of the width of the thorax. Radiologic enlargement does not necessarily mean cardiomegaly is present.
How will pneumothorax present on CXR (most basic)
Extremely radiolucent lung, missing landmarks of normal lung hila. May also have additional opaque mass (collapsed lung) and tracheal/mediastinal deviation (tension pneumothorax). Be sure to check apices for apical pneumothrorax.
Appearance of COPD (and asthma) on CXR
Enlarged lung fields, flattened diaphragms, hilar markings appear ‘cut-off’ heart APPEARS smaller.
How will fluid appear within the lung?
As an inflitrate. Can be streaky (in connective tissue), patchy (alveolar), diffuse (lobar), or white out.
How do the lungs appear in CHF?
Increased vascular markings in upper lobes described as “deer antlers” or butterfly hilum.
How does pulmonary edema appear on CXR?
Usually white-out with normal heart size. Can be caused by CHF, ARDS, Renal failure, stroke, fluid overload.
How does an aneurysm appear on chest xray? What is the key landmark?
Widened mediastinum (>8cm) with possible L sided effusion.
What is the avg US environmental radiation exposure?
3 mSv/yr. Higher in populated areas and higher elevations.
How much radiation is there in a chest xray? body CT?
0.1 mSv; 10mSv
What is the main reason to order a skull plain film?
Looking for metal fragments. Can also order for sinusitis (but remember that kids under 5-6 don’t have pneumatized sinuses)
What do you order if you are concerned about skull fracture?
non contrast head CT
What are the views of a head film?
PA (Caldwell), Waters (for sinuses) and lateral.
What is an orbital blow-out fracture?
Blunt force against medial or inferior orbit of eye. You will see the fracture and an associated air-fluid level.
What are the 3 types of maxillary fractures?
Key sign is abnormal occlusion of upper teeth
How to diagnose a nasal bone fracture.
No xray needed. Diagnose clinically. May see displacement of bones on xr.
What is the best view for visualizing a mandibular fracture?
panoramic view dental (lateral, AP, and/or CT)
What are the ‘ABCS’ of spine films?
A- alignment- no step-offs
B- Bony integrity (are all bones smooth?)
C- Cartilage (Is the joint space narrowed?)
S- Soft tissue- is there any swelling?
What are the standard views for a C-spine?
AP, lateral (to C7), odontoide
When should you order a c-spine?
posterior midline (bony) tenderness, intoxication, focal neurological deficit, mental status changes following injury.
What process does a straight cervical spine suggest?
Muscle spasm
What are the rules for assessing prevertebral space (x-ray shadow anterior to vertebral bodies) in a c-spine?
C3 and above should be <7mm, C7 to C4 should be no wider than 21mm.
What are the 3 radiologically stable c-spine fracture types?
Clay shoveler’s, wedge, extension teardrop
Clay-shoveler’s fracture
Avulsion of a cervical spinous process. Typically due to flexion injury. Usually at C6-T1.
Wedge fracture
Flexion injury. Compression of anterior part of a vertebral body, accompanied by loss of lordosis.
Extension teardrop
Fracture of c-spine in which a piece of anteroinferior vertebra body is avulsed. Most often in C2. Caused by extension.
What are the 5 radiologically UNSTABLE c-spine fractures?
- Flexion teardrop
- Hangman’s
- Burst
- Jefferson’s
- Odontoid
Flexion teardrop.
Unstable c-spine fracture. Small fragment of anteroinferior portion of vertebal body is broken off WITH POSTERIOR DISPLACEMENT. Results in disruptions if ligaments and soft tissue, as well as spinal cord compression.
Hangman’s fracture
Unstable c-spine fracture due to an extension injury (MVC). Bilateral c2 pedicle fracture with anterior displacement of the anterior part of c2.
Features (lat view)
- Prevertebral soft tissue swelling
- Avulsion of anterior inferior corner of c2 associated with ligament rupture
- Anterior dislocatrion of c2 vertebral body
- Bilateral c2 pars interarticularis fractures.
Burst (fracture)
Unstable c-spine fracture. Compression of vertebral body (loss of both anterior and posterior vertebral body height). Usually mid-cervical spine.
Jefferson fracture
Unstable c-spine fracture of C1 (ATLAS) causing bilateral, lateral displacemement.
What are the 3 types of odontoid fractures? which is most stable?
2 is least stable.
What is the most common fracture of the T-spine?
Compression fracture due to hyperflexion.
When do you order an L-film for a patient with low back pain?
- If it’s lasted more than 4 weeks
- Direct trauma
- Neurological abnormalities
- You suspect malignancy
How does spondylolysis appear on an L-spine? Where does it occur and to whom?
Typically occurs with adolescent athletes at L5 vertebrae. Looks like a “collar” around the scotty dog model representing a fracture.
Spondylolisthesis
Anterior slippage of the vertebral column. Usually a result of a bilateral spondylolyisis and occurs at L4-L5 or L5-S12.
Greenstick fracture
fracture does not extend all through whole bone, only a break on one side of cortex. SOmetimes the other side is buckled together resulting in a denser (whiter) appearance (called a buckle or torus fracture).
How large should the interphalangeal and metacarpal-phalangeal joint spaces be? What does it mean if they’re different?
~1mm. If different, suggests dislocation.
Some lovers try positions that they can’t handle
Bones of wrist: Scaphoid, lunate, triquetrum, pisiform, trapezium, trapezoid, capitate, hamate.
You should never see a “moon on the wrist”. What does this mean.
In lat view, suggests lunate disloaction.
Smith’s and Colle’s fractures of the distal radius
Depend on displacement of distal fragment. Smith’s = volar, Colle’s= dorsal. Colle’s>Smith’s
Which fat pads should you see in the Elbow?
Normally you can see the anterior fat pad, but it shouldn’t be sailed out. The posterior fat pad should not be visible, and suggests fracture if it is.
What are the 4 types of unstable pelvic fractures?
Malgaigne (A), Open book (B), Bucket (C), Straddle (D)
What are the two most common locations for a hip fracture?
Femoral neck and intertrochanteric.
How does the less common POSTERIOR glenohumeral fracture look on XR?
Head of humorus looks more like light bulb than walking stick. Joint space is less uniform.
What should you always check for in a sprained anckle?
Posterior calf tenderness that might suggest spiral fracture of the fibula.
Gadolinium
Contrast used for MR imaging.
What are the 3 imaging planes for CT and MRI?
Hyperintense vs hypointense
Terms for MR images. Hyper means bright. Hypo means dark.
What is the difference between T1 and T2 weighted MR images?
T1- White matter is white, grey matter is grey, fluid is DARK.- for anatomy
T2- White matter=grey, grey matter=LIGHT, fluid=BRIGHT- for pathology
When to use PICC line vs tunneled catheter vs subcutaneous port?
>7 days= PICC
1-12 weeks= PICC line OR tunneled catheter
12 weeks - 6 months= tunneled cath
>6 months= subcutaneous port
