MRA

Question 1

Name 4 types of MRA

Answer 1

1) TOF
Flow-related enhancement in GRE
2) PC
Phase accumulation in bipolar gradient
3) Fresh blood ECG-gated
Half-Fourier TSE: diastole-systole
4) CE
T1w GRE

Question 2

Four pros and cons of 2D vs 3D TOF MRA?

Answer 2

2D more sensitive to slow flow
2D faster acquisition
3D better through-plane resolution
3D higher SNR

Question 3

What sequence is used for TOF MRA?

Answer 3

T1w GRE

Question 4

How does fresh blood ECG-gated MRA work?

Answer 4

arterial angiogram = diastole - systole

fast arterial spins from systole are washed out by TOF effect

Question 5

How does TOF MRA work?

Answer 5

T1w GRE - short TE, TR to saturate stationary spins in slice
Flow-related enhancement as unsaturated spins roll in

Question 6

How does PC MRA work?

Answer 6

Bipolar gradient

Stationary spins accumulate no net phase in gradient

Moving spins accumulate phase in gradient proportional to velocity

Signal proportional to velocity in phase image

Question 7

How does CE MRA work?

Answer 7

Monitoring pulses, or small pre-bolus to gauge estimated time for maximum arterial enhancement

CA injection

Image on injection and at maximum arterial enhancement

Subtract images to reveal arterial angiogram