Visual diagnostics in praxis

Question 1

Why should MR be performed within 48h from surgery?

Answer 1

To be able to discriminate blood from remnant tumor.

Question 2

Why should DWI sequences be added postoperatively?

Answer 2

To enable detection of perioperative ischemia

Question 3

What is pseuodoprogression?

Question 4

What is pseudoregression?

Question 5

Can solid masses be bright on an unenhanced T1 weighted MRI?

Answer 5

No.
Only blood or proteinacious fluid OR Fat can be bright on an unenhanced T1 MRI.

Question 6

In general, all extra-axial masses , i.e. masses outside of the brain like the pituitary gland and stalk, will enhance because they do not have a blood-brain barrier.

If you have a non-enhancing extra-axial mass, there are three possibilities. Which?

Answer 6

1. Rapid arterial flow (eg. large blood vessel).
2. No cellular tissue (eg. cyst).
3. No blood supply (eg. infarcted mass

Question 7

So, what is probably an extraaxial mass that has high T1 signal but no Gd enhancement representing?

Answer 7

That must be something with blood or high protein content or fat.

It is not

Question 8

In general there are three things that are black on MRI (T1)-which?

Answer 8

• Air
• Bone
• Rapid flow void

Question 9

type of vision defect?
- prefixed chiasm

Answer 9

homonymous hemianopsia