FRCR MCQ ---MRI (Inversion recovery)

MRI (Inversion recovery)

Q1. The MRI technique used to null signal from fluids is
a.FLAIR
b.STIR
c.GRE
d.HASTE

Q2.The MRI technique used to null signal from fat is
a.FLAIR
b.STIR
c.GRE
d.RARE

ANS.Q1===a----The MRI technique used to null signal from fluids                              is FLAIR(fluid attenuated inversion recovery )
        Q2===b---- The MRI technique used to null signal from fat is                               STIR(short-tau inversion recovery)

Inversion recovery

• In this sequence type, the magnetization is ‘prepared’ before the initial 90-degree excitation pulse by the addition of an 180-degree ‘inversion’ pulse. 
• The signal obtained will be influenced by the relative degree of recovery experienced by the spins along the z-axis. 
• The inversion time (TI) is the time allotted for this recovery process to evolve between the 180-degree inversion and 90-degree excitation pulses. The inversion pulse introduces heavy T1 weighting into this sequence.

Specific forms of the technique -



www.mriworld.org

• A== fluid attenuated inversion recovery (FLAIR) where the TI is chosen so that the magnetization from fluids is nulled (≈2200 ms) in the detection (x–y) plane and TE is long (80–100 ms), introducing a lot of T2 as well as T1 weighting. Thecombination  of fluid nulling with T2 weighting is particularly useful in assessing lesions with prolonged T2 adjacent to fluid structures (e.g. periventricular demyelination).

•  B====In short-tau inversion recovery (STIR), T1 is kept short, and is typically used to null signal from fat. An example of its use in this context is in the delineation of breast lesions and orbital pathology.