Introduction to Neuroradiology Flashcards
What is fluoroscopy?
It is real time XR. Allows for adjustments if needed.
Uses contrast.
Includes swallowing studies, angiography, myelography.
What does barium swallow eval?
Dysphagia
Epigastric pain
GERD
Sort of replaced by endoscopy.
What does digital subtraction angiology refer to?
Angiography
How is angiography performed?
An image is taken before to “subtract” bones and tissues after contrast is given.
It is fairly invasine as a catheter is needed.
What is myelography?
Used to visualize the SC.
Requires a lumbar or cervical puncture with contrast.
F/U CT needed to eval contrast.
What do you use for carotid stenosis?
Ultrasound
What do you use to visualize fontanelles?
Ultrasound
What do Hounsfield units measure?
Radiodensity in a CT (water is 0 HU)
Hyperdense
Hypodense
Hyper: white/bright
Hypo: black/dark
Wider windows of HU compare what?
Tissues of greater difference in HU (i.e. bone and air)
Narrow windows of HU compare what?
Tissues of similar HU (i.e. brain and blood)
What is the window?
What is the level?
Window is range of HU.
Level is middle of window.
What does CT have low sensitivity to?
Posterior fossa
What is CT used for in the brain?
Skull, vertebrae.
Ventricles (hydocephalus, masses)
Hemorrhage, ischemia
Calcification (lesion characterization)
When is non-contrast CT used?q
In pts w/ head/spine trauma and acute stroke.
It is the preferred study within 3 hrs of acute onset.
When is contrast used?
When sx last more than 3 hrs.
No contrast:
Trauma R/O hemorrhage Hydrocephalus Dementia Epilepsy
Yes contrast:
Neoplasm
Infection
Vascular dz
Inflammatory dz
What is the risk of MRI contrast in a patients with renal insufficiency?
Nephrogenic systemic fibrosis
What does it mean when a tissue “enhances”?
What does it reflect?
Gets brighter with contrast.
Reflects the vascularity of the tissue.
What structures will enhance w/ IV contrast (outside of BBB)?
Cerebral BVs Meninges Pineal gland Pituitary Choroid plexus
How are contrast studies and angiograms different?
Contrast is used to eval where the breakdown is in the vessls in the BBB, while angiograms are used to visualize the BVs.
MRI
Hyperintense
Hypointense
Hyperintense: white/bright
Hypointense: black/dark
What is MR used for in the head?
Eval ischemia, chronic/subacute sx, tumors, infection.
T1
CSF is dark (hypointense)
White matter is bright (hyperintense)
T2
CSF is bright (hyperintense)
White matter is dark (hypointense)
T2 FLAIR
Removes CSF from T2 image.
Good for eval edema/abscesses (high protein content)
Dying neurons stop Na/K pumps and water accumulates = edema.
