Imaging and Pathological Correlates of Clinical Neurological Disease Flashcards
On a __________ sequence, fluid is hypointense (black), muscle is isointesnse (grey), and fat is hyperintense (white).
T1-weighted (pre and post-contrast)
In T1-weighted sequences post-contrast, contrast should be taken up by the tissues and lead to increased – hyperintensity or hypointensity?
hyperintensity (white)
On a T2-weighted sequence, describe the intensities of the following:
Fluid
Muscle
Fat
Fluid – hyperintense
Muscle – isointense
Fat – hyperintense
what sequence is BEST to ID pathology?
T2-weighted
because most pathological changes (edema, inflammation, cancer, or hemorrhage) would be T2 hyperintense
A T2-weighted FLAIR sequence makes it easier for us to discriminate …
pathology next to NORMAL fluid-filled structures
because it nulls out pure fluids (CSF) as hypointense, but pathological fluids show up hyperintense.
Susceptibility weighted or sensitive sequences take advantage of paramgnetic, diamagnetic, and ferromagnetic properities interacting with the local magnetic field to detect ___________.
blood
which will cause LOSS of signal and appear hypointense (black)
what false positives can occur on a susceptibiltiy weighted or sensitive sequence?
air or bone
for bone, you can differentiate by looking at the T2-weighted. The hypointensity on the susceptibility weighted or sensitive sequence and the T2-weighted sequences would be the SAME intensity of black on both sequences if it were bone.
what sequence did FLAIR replace?
proton density (PD-weighted)
what can cause vacuolization in the white matter?
edema
__________ is the antegrade degeneration of the axon distal to the site of injury.
wallerian degeneration
which initiates the neuroinflammatory cascade.
What is your interpretation of a patient who has paresis 1 grade more severe in the back than the front limbs?
this patient has multifocal lesions.
How can you identify FCE on an MRI?
it appears as a intramedullary hyperintensity centered over the vertbral bodies, not solely the discs.
what necropsy findings would there be in a case of FCE?
malacia of the gray matter.
gray matter is more metabolically active and has higher blood supply demands, so it is usually the first area affected with ischemic myelopathies.
what histopathology findings would be found in a case of FCE?
emboli within the vascular supply of the spinal cord. Depending on which artery was affected (dorsal spinal vs dorsal radicular vs ventral radicular vs ventral spinal) will affect which area of the gray matter is affected.
How does the embolism enter the spinal vascular system?
unknown but there are many theories.
