14. Imaging of Head and Neck (Schirmer) Flashcards
What is MRI contrast made of?
What are the possible complications?
Gadolinium.
Nephrogenic systemic fibrosis in pts with renal insufficiency.
What are the three types of flouroscopy discussed?
Barium Swallow
Angiography
Myelography
What is bright and dark in a T2 MRI?
T2 = CSF is bright, white matter is dark.
(T2 = too bright)
What is a T2 FLAIR good for?
Visualizing edema.
(FLuid Attenuated Inversion Recovery)
What is bright and dark in T1 MRI?
What is it good for?
T1 = CSF is dark, white matter is light.
Good for anatomy.
How would you want to set up your CT to look at bone?
Large window, high level.
W:1000 HU L: 400
When would an MRI be preferable to a contrast CT?
If blood (and therefore contrast) cannot get to the area - such as in ischemic areas..
How might you want to set up your CT to evaluate soft tissue?
You will want a narrow window (eg: 90 HU window) with a level (center of the window) of 50.
Soft tissue = W: 90HU L: 50HU
Why might one prefer a CT angiography over a fluoroscopy angiography?
Why might one prefer fluoroscopy?
CT angiography is not invasive, because — unlike fluoroscopic angiography — you don’t have to inject contrast directly into the artery. In CT angiography the contrast is administered via an IV bolus.
Also in CT angiography, you can evaluate blood vessels from the heart to the point of interest, unlike fluoroscopic angiography - which is more distal.
All that said, fluoroscopy angiography has a higher resolution.
When is contrast indicated for a CT, and when is it not indicated?
- Contrast indicated:
- Neoplasm
- Infection
- Vascular disease
- Inflammatory disease
- No contrast
- Trauma
- To rule out hemorrhage
- Hydrocephalus
- Dementia
- Epilepsy
What is CT contrast made of?
What are possible complications?
Iodine (based).
Anaphylaxis.
