• Object ID: 00000018WIA30DE1970GYZ
  • Topic ID: id_40023978 Version: 1.2
  • Date: Jan 9, 2022 12:21:11 PM

DE Prepared

DE Prepared applies a 90/180/90° RFDE preparation pulse to produce more T2-weighted contrast with Fast GRE.

Figure 1. DE Preparation pulse: 1 = prep pulse

Given a constant TR and flip angle, the longer the prep times the more dephasing, and the more T2-weighting. Some blurring can occur with prep pulses. Centric phase-encoding is used to minimize the blurring

DE Prepared is only compatible with 2D, sequential, Fast GRE sequences.

Figure 2. DE Prepared: knee images

The initial 90° pulse creates transverse magnetization, which immediately begins to dephase. The amount of dephasing is controlled by the prep time. The longer the prep time, the more dephasing, and the more T2-weighting. The remaining transverse magnetization is rephased by the 180° RF pulse.

After another delay (prep time) wherein more T2 decay can occur, a 90° pulse is applied, driving the remaining transverse magnetization back to longitudinal.