Neuroimaging

Question 1

Which neuroimaging method gives the best view of the brain/ spinal cord?

Answer 1

MRI, but it’s less practical

Question 2

T1W MRI

What does it highlight? How does CSF look (high signal or low signal)?

Answer 2

1. Highlights anatomy
2. CSF is dark (low signal)

Question 3

T2W MRI

What does it highlight? How does CSF look (high signal or low signal)?

Answer 3

1. Highlights pathology
2. CSF is bright (high signal)

Question 4

What is FLAIR?

Answer 4

Fluid Attenuation Recovery

Similar to T2W, but the visually distracting high signal of CSF is removed from the images

Question 5

How do most lesions appear on T2W or FLAIR?

Answer 5

Lesions appear bright (high signal)

Question 6

How do acute infarcts look on MRI? On CT? Which is best?

Answer 6

MRI is best

MRI uses diffuse weighted imaging which provides the earliest infarct detection (because water diffusion is impaired in ischemia). Infarcts on T2W or FLAIR appear bright.

On CT, infarcts appear hypodense and early infarcts may not be visible.

Question 7

How does edema appear on CT? On MRI T2W/Flair?

Answer 7

1. Appears as a hypodensity or lucency on CT
2. Appears as high signal intensity on MRI/FLAIR

Question 8

How do you evaluate degenerative spine disease if an MRI cannot be done?

Answer 8

If MRI cannot be done, a spinal CT may require intrathecal contrast (myelogram) to outline the spinal cord and its nerve roots.