Fast T1-weighted imaging using GRASE sequence for the female pelvis

GRASE sequence, a combination of TSE and gradient echo, has been developed as a fast T2-weighted imaging technique. We have modified the GRASE sequence to be used for fast T1-weighted imaging of the female pelvis. In this article, we compared image quality and incidence of artifacts between T1-weighted GRASE images and conventional T1-weighted SE images. In a phantom study, signal-to-noise ratio was inferior in the GRASE images relative to corresponding on SE images. Susceptibility and chemical shift artifacts seen in GRASE images were seen with almost equal incidence in SE and TSE images. In a clinical study, we compared GRASE images with SE images in six patients with endometrial cysts and four patients with dermoid cysts. The overall image quality obtained with GRASE sequence was satisfactory in all patients and was almost identical with that obtained with SE sequence. GRASE images demonstrated endometrial cysts and dermoid cysts as clearly as did SE images. T1-weighted GRASE imaging, however, has a relatively long TE (35 ms) for T1-weighted images, which makes the signal intensity of urine and uterine endometrium with long T2 values higher than in SE images. In conclusion, GRASE sequence can be used for fast T1-weighted imaging of the female pelvis because of short imaging time. (author)