What is the name of the time interval between the 180 and the first 90-degree RF pulse in Inversion Recovery?

In the context of Inversion Recovery MRI sequences, the time interval between the 180-degree and the first 90-degree RF pulse is known as Tau. This interval is crucial because it determines the timing of the 90-degree pulse after the 180-degree inversion pulse, which effectively controls the recovery of longitudinal magnetization. By adjusting the Tau time, radiologists can manipulate the contrasting properties of different tissues, as it allows for optimum signal recovery time between the two RF pulses.

This period is essential for creating the inversion recovery contrast mechanism, which enhances the visibility of certain tissues relative to others, such as distinguishing between fat and water or highlighting pathology. Understanding Tau's role in the timing of RF pulse sequences is vital for optimal imaging results in MRI.