MRI MRI Pulse Sequences

Question 1

In a spin-echo sequence, which combination of TR and TE produces a T2-weighted image?

Accepted Answer

Long TR, long TE

Answer

Short TR, short TE

Answer

Short TR, long TE

Answer

Long TR, short TE

Question 2

Fast spin-echo (FSE/TSE) sequences acquire multiple lines of k-space per TR using which approach?

Accepted Answer

A single 90° pulse followed by multiple 180° refocusing pulses (echo train)

Answer

Multiple 90° pulses with a single 180° refocusing pulse

Answer

Rapidly toggling the frequency-encoding gradient

Answer

Using a series of partial flip-angle pulses

Question 3

Which gradient-echo sequence uses a very short TR and a spoiler gradient to eliminate residual transverse magnetization before the next RF pulse?

Accepted Answer

Spoiled gradient echo (SPGR/FLASH)

Answer

Steady-state free precession (SSFP/TrueFISP)

Answer

FIESTA

Answer

GRASS

Question 4

What does the acronym STIR stand for, and what tissue does it primarily null?

Accepted Answer

Short-T1 Inversion Recovery — nulls fat signal

Answer

Steady-state T1 Inversion Recovery — nulls water signal

Answer

Short-TE Inversion Recovery — nulls fat signal

Answer

Standard Tissue Inversion Recovery — nulls all tissue equally

Question 5

Diffusion-weighted imaging (DWI) measures the random Brownian motion of water molecules. Restricted diffusion (e.g., in acute stroke) appears as:

Accepted Answer

High signal on DWI, low ADC

Answer

Low signal on DWI, high ADC

Answer

High signal on DWI, high ADC

Answer

Low signal on DWI, low ADC

Question 6

Which MRI sequence is used to visualize flowing blood as bright signal ('bright blood') without contrast injection by exploiting the inflow of unsaturated spins into the imaging slice?

Accepted Answer

Time-of-flight (TOF) MRA

Answer

Phase contrast MRA

Answer

Contrast-enhanced MRA

Answer

VIBE