Which field strength would require the shortest TI time to suppress the signal from fat in a STIR sequence?

In a Short Tau Inversion Recovery (STIR) sequence, the inversion time (TI) is critical for effectively nullifying the signal from fat. The TI time required to achieve this depends on the magnetic field strength being used.

At higher field strengths, such as 1.5T or 3.0T, fat experiences a higher precessional frequency and shorter T1 relaxation times. This means that the time needed to effectively null the fat signal becomes longer because the fat tissues recover more quickly and reappear before the imaging sequence captures the necessary data. Conversely, at lower field strengths, like 0.5T, fat has a longer T1 relaxation time, which allows for a shorter TI time to adequately suppress the fat signals.

Given this relationship, a 0.5T field strength would indeed require the shortest TI time to effectively suppress the signal from fat in a STIR sequence due to the relative differences in fat's T1 recovery times compared to higher field strengths. Therefore, this is why the identification of 0.5T as requiring the shortest TI is correct.