Radiology

Question 1

Mri findings for early subacute blood (3-7days)

Answer 1

Bleed Die (B = 3, D = 7)

Bright on T1, dark on T2

Question 2

Mri findings for hyperacute blood (<1 day)

Answer 2

I bleed in one day

Isointense T1, bright T2

Question 3

Mri findings for acute blood (1 - 3 days)

Answer 3

I die 3 days after I bleed

Isointense T1
Dark T2

Question 4

Mri findings for chronic blood (>1month)

Answer 4

Die Die

Dark on T1
Dark on T2

Question 5

Mri findings for early subacute blood (7-14days)

Answer 5

Bleed Bleed 2 weeks

Bright t1 and t2

Question 6

Difference between PET and SPECT

Answer 6

Both are nuclear scans, that rely on gamma rays to detect and create the image.

PET scan: Positron emitting tomography.
Uses a tracer which produces positrons, typically FDG18.
When positron is emitted at the tissue of interest, it collides with an electron, to form 2 gamma rays. Only gamma rays ?directly opposite each other are picked up by camera.
Gives a crisper image.

SPECT scan: Single photon emission CT.
Uses a tracer which produces gamma rays directly.
eg. Technetium.
Produces one gamma ray, gets picked up by the detector/collimator.