Intro to Neuroradiology Flashcards
How is electromagnetic radiation created?
electron beam targets tungsten –> radiation
What are the pros and cons of XR?
pros: cheap, fast
cons: radiation, lack of soft tissue detail
What is fluoroscopy?
real-time X ray
used for diagnosis and intervention (swallow studies, angiography, myelography)
*uses contrast
What are the pros and cons of barium swallow?
pros: live demo of swallow coordination
cons: time consuming, contrast, radiation
What is myelography?
ueses fluoroscopy
cervical or lumbar puncture
inject contrast intrathecally –> can see spinal cord
f/u w/ CT to eval contrast
What do you use myelography for?
spinal stenosis, nerve root compression
CSF leak
if MRI contraindicated
Which imaging technique can allow you to see the subarachnoid space?
myelography
what imaging technique can be used to quantitate blood velocity?
U/S
What are Hounsfield units?
measure radiodensity
0 HU = water
What is white and dark in CT?
hyperdense = white hypodense = dark
What body substances are less dense than water?
fat
air
What are the level and window of the houndsfield scale?
level = center of window
window = width of HU in generated view of CT
narrow windows compare areas w/ similar densities
What is the major pro of CT?
most beneficial for ruling out large pathology
when would you use CT contrast?
neoplasm
infection
vascular disease
inflammatory disease
What type of contrast is used in CT?
In MRI?
CT = iodine
MRI = gadolinium
*both bright on imaging
What are the risks of CT contrast?
risk of allergic rxn to iodine contrast
What is the contrast used in MRI and how does it work?
What are the risks?
gadolinium = paramagnetic metal that increases T1 relaxation of nearby water protons (looks bright on MRI)
risk of nephrogenenic systemic fibrosis in pts w/ renal insufficiency
What happens if you see enhancement in the brain from IV contrast?
BBB is absent or dysfunctional
How does MRI work in general?
large magnet aligns all protons –> radiowaves passed and returning signals are converted into an image
What are the basic MRI terms?
hyperintense = white/bright hypointense = dark
What do you see on T1 MRI?
CSF = dark (hypointense)
white matter = bright (hyperintense
good for anatomy
What do you see on T2 MRI?
(To Fkn Bright)
T2–> csF = Bright (hyperintense)
white matter = dark
What is T2 Flair?
removes CSF from T2 image
enhances fluid w/ increased protein content = great for seeing edema/abscesses
dying neurons sell as Na/K pumps stop working –> water accumulates within the cell
*bright area will be damaged area
