MRI MRI Sequences and Protocols

Question 1

In a spin echo (SE) sequence, increasing the repetition time (TR) while keeping TE short primarily results in:

Accepted Answer

Decreased T1 weighting (more proton density/T2-like contrast)

Answer

Increased T2 weighting

Answer

Increased T1 weighting

Answer

Increased SNR only with no contrast change

Question 2

FLAIR (Fluid-Attenuated Inversion Recovery) suppresses which signal and is most useful for detecting:

Accepted Answer

CSF signal; periventricular and cortical lesions

Answer

Fat signal; bone marrow edema

Answer

Blood signal; hemorrhage

Answer

Muscle signal; soft tissue tumors

Question 3

Which MRI sequence is most commonly used for evaluating liver lesions using T2 contrast with heavy T2 weighting for the bile ducts?

Accepted Answer

MRCP (heavily T2-weighted 3D or thick-slab)

Answer

T1 in-phase/opposed-phase

Answer

DWI b1000

Answer

STIR of the abdomen

Question 4

Gradient echo (GRE) sequences differ from spin echo sequences primarily because GRE:

Accepted Answer

Uses a gradient reversal to form an echo, making it sensitive to magnetic susceptibility (T2*)

Answer

Uses a 180° refocusing pulse to eliminate field inhomogeneity effects

Answer

Always requires longer scan times

Answer

Cannot be used for dynamic contrast imaging

Question 5

Which parameter directly controls the degree of T2 weighting in a spin echo sequence?

Accepted Answer

TE (echo time)

Answer

TR (repetition time)

Answer

Flip angle

Answer

Bandwidth

Question 6

Magnetization transfer contrast (MTC) in MRI is based on the exchange of magnetization between which two proton pools?

Accepted Answer

Free water protons and bound macromolecular protons

Answer

Fat protons and water protons

Answer

Intracellular and extracellular water

Answer

Arterial and venous blood