Radiology Flashcards
Widening of the mediastinum on PA film
Think aortic dissection (thoracic)
When are AP films the answer
When the patient is unstable and too sick to stand up
CXRs in the ICU are AP films
What are decubitis films good for?
When the diagnosis of an infiltrate from pneumonia cannot be distinguished from an effusion
Why are lateral CXRs better than PAs at detecting an effusion
Lateral CXRs can detect as little as 50-75 mL of effusion
PAs become abnormal with an effusion of about 200-300 mL
Lateral CXRs are also used to identify the precise location of an infiltrate
Abdominal x-ray is good for…
Ileus or SBO
- Not accurate for kidney stones (will miss 20% of cases)*
- Not reliable for finding air under the diaphragm*
For perforation of the bowel, what is the best initial study?
Upright CXR (NOT abdominal x-ray)
Best initial test for osteomyelitis
X-ray of the bone: elevation of the periosteum
It will take at least two weeks for the bone x-ray to become abnormal with osteomyelitis; however, only obtain an MRI of the bone or nuclear bone scan if the x-ray is normal
When are CT scans of the head (WITH contrast) indicated?
Cancer and infection
Cannot distinguish between neoplastic disease and an abscess by CT or MRI, but it is the best initial test
What must be done before ordering a contrast study?
Hydration with saline (possibly use bicarbonate or N-acetylcysteine with mild renal insufficiency)
Stop metformin prior to using contrast
Do not use with severe renal railure
Abdominal CT should be performed with…
IV AND Oral contrast
Most accurate test for nephrolithiasis
Abd CT
Most accurate test for diverticulitis
Abd CT
True/False
CT is neither the “best initial” nor “most accurate” test of bone
True
When is chest CT the answer on a test?
Hilar nodes
Mass lesions
Cavities
Interstitial lung disease (shows parenchymal lung disease, CXR only shows interstitial infiltrates)
Pulmonary emboli
MRI is the most accurate test of all CNS diseases with the exception of looking for…
hemorrhages
