Neuroradiology Fellowship 1
Terms
undefined, object
copy deck
- Differentiate demyelinating disease from small vessel ischemic changes
-
1) Look for Dawson's fingers. The more linear the better.
2) Look for involvement of the optic nerves, optic pathways, corpus callosum, and U-fibers. - Best sequence on conventional MR to see gray matter lesions in MS?
- FLAIR
- Earliest sign of MS on conventional MR?
- Enhancement
- Then what?
- Then the high signal on FLAIR develops. Much harder to see on T2WI.
- Appearance of MS lesions on T1WI
- Most commonly they are isodense to white matter. But, if they are seen, it means one of 2 things. . . severe active lesion with a lot of edema or chronic burned out lesion with irreparable brain injury.
- How long does enhancement last?
- Days to weeks
- Appearance of enhancement in MS
- Start out as homogeneously enhancing lesions, and progress to ring enhancing lesions. Shape of lesion is variable though.
- Best method of assessing for active disease?
- LOOK FOR ENHANCING LESIONS. Lesion enhancement is much more sensitive indicator of active disease than clinical exam because most MS lesions are clinically silent.
- Affects ability to detect MS lesions
-
Field strength
Gado dose -- Triple dose detects more lesions and increases size of enhancing areas. - Differential for bilateral thalamic pathology
-
Infarct
Encephalitis
Lymphoma or GBM - Infarcts specifically
- Arterial versus venous
- Arterial infarcts
- Determine based on which part of thalamus involved
- Anterior thalamus only
- Think basilar tip
- More of thalamus involved
- Think artery of Percheron
- What is artery of Percheron
- Arterial variant where single artery comes out of the basilar to supply much of the thalamus. If you have that variant, and it goes, you get screwed.
- Venous
- Deep venous system infarcts, like internal cerebral veins or vein of Galen.
- Type of encephalitis
- West Nile especially known for this
- Why lymphoma and GBM affect thalamus bilaterally
- They go across the massa intermedia (interthalamic adhesion) or habenula (posterior to interthalamic adhesion)