Chest, Cardiac, GI, and Neuro Imaging Flashcards
what can chest x-rays help with?
- differentiate/resolve objects based on density
- high density objects → solids such as bone and metal appear white
- low density objects → gas and lungs appear black
- water-based tissues somewhere in between
- calculate cardiac ratio
- find lung manifestations of heart disease → pleural edema and effusion
when are chest x-rays used?
frequently with chest pain presentation
its cheap and has small radiation exposure
what are the 2 types of echocardiograms?
What is the TEE the gold standard for?
- Transthoracic echocardiogram (TTE)
- Transesophageal echocardiogram (TEE) → gold standard for excluding intracardiac thrombus
what is doppler echocardiogram used for?
- visualize blood flow → helps ID turbulent regions
- gold standard to find valvular abnormalities
what is myocardial perfusion imaging? What is it used for?
- heavy element radioisotopes are used to mark areas of myocardial perfusion
- imaging the heart when exposed to these markers allows us to ID areas of low perfusion (indicating ischemia)
- nuclear stress test → imaging done before and after stress
what is a cardiovascular MRI? what is it used for?
- noninvasive use of magnetic fields and radiowaves to form images of structures in the heart
- downside → very expensive, contrast exposure
- produces moving and still images
- gold standard for assessing cardiac structures and function
what is cardiac catheterization?
involves insertion of catheter into chambers of the vessels of the heart
- allows for therapy (stents) and diagnostics
- downsides
- radiation exposure
- expensive
- invasive (minimally)
describe the 2 types of cardiac catheterization
- Right Heart Cath → insert through vein to measure R heart and pulmonary artery pressures
- Left Heart Cath → insert through artery to measure L heart pressures, insert dye for coronary angiography
what is the gold standard for assessing intracardiac pressures and CO?
Right heart Cath
what is the gold standard for visualizing coronary arteries and identifying stenosis?
Left heart cath
what is cardiac CT? what is used for?
- it assess ______*
- it visualizes _______*
computed tomography of the heart → extensive heart x-ray
- used to assess extent of coronary stenosis
- visualize thoracic aorta
what are the benefits/drawbacks of cardiac CT?
- Benefits
- less invasive than catheterization
- produces 3D models
- Drawbacks
- still requires radiation exposure
- contrast that damages kidneys
what are plain films in the abdominal region useful (with limitations) for? (3)
- bowel obstruction and ileus
- gross free air
- radiopaque foreign body
abdominal plain films have a low yield or are insensitive for what things?
- abdominal pain
- stones
-
any soft tissue abnormality
- inflammation
- abscess
- masses
what is pneumoperitoneum? list some causes
the presence of air within the peritoneal cavity
- perforated hollow viscus
- peptic ulcer disease
- ischemic bowel
- necrotizing enterocolitis
- appendicitis
- diverticulitis
- malignancy
- inflammatory bowel disease
- trauma
- foreign bodies
- iatrogenic (e.g. colonoscopy)
- post-op
- peritoneal dialysis
what is Rigler’s sign and what is it an indication for?
“double-wall sign”
sign of pneumoperitoneum seen on abdominal radiograph when gas is outlining both sides of the bowel wall
its an indication of free air enclosed within the peritoneal cavity
what are some causes of small bowel obstructions?
- adhesions
- hernia
- stricture (inflammatory, ischemic, XRT)
- tumor
- intussusception
- volvulus
- gallstone
what is pneumatosis and what are some causes?
intramural gas
- ischemic bowel
- “benign” incidental
steps to diagnose strokes with imaging
- step 1 → history and exam
- step 2 → imaging tests
- CT scan is first
describe typical features of CT-scan of the brain
- normally delineated curves
- surface appears different than tissue below the surface
- symmetrical
how long does it take for brain changes to develop enough to be seen with CT?
12-18 hours
describe abnormal features on a brain CT and what they may mean
- may be able to help visualize a clot
- MCA hyperdense sign → signifies a clot
- swelling
- brain surface appears similar to deeper tissues
- lack of differentiate between gray and white matter
- asymmetry between R and L = “mass effect”
- causes compression on other parts of the brain
Head CTs are good at identifying _________
hemorrhagic strokes
describe CT angiography
what can it hide?
- dye injected into bloodstream
- blood vessels show area of stroke
- can hide normal tissues and can just look at vessels
MRIs of the brain can help show what?
what type of changes?
- brain changes faster (ischemic changes)
- can be used to measure blood flow
what is a Flair MRI?
- an MRI in which the computer removes fluid signature
- allows for a very clear image of brain tissue
what type of CT is most commonly ordered for looking at the brain?
CT w/o contrast
CT angiograms are used to visualize vessels not parenchyma
things to look for with brain CTs
- what would bright structures indicate?*
- What would dark structures indicate?*
- landmarks
- asymmetry
- hyper/hypodensity (light vs. dark)
- bright → calcified structures, acute blood
- dark → chronic lesions, fluids
describe bright/dark findings on brain T2/Flair MRIs
bright (5)
dark (4)
- Bright
- cytotoxic edema
- vasogenic edema
- subacute bleed
- hydrocephalus
- inflammatory lesions
- Dark
- paramagnetic substances
- protein rich
- flowing blood
- acute bleed
list bright/darkfindings on brain T1 MRI
bright (4)
dark (2)
- Bright
- paramagnetic substances
- protein rich
- fat
- subacute lesions
- Dark
- edema
- chronic lesions
