Optimizing cine MRI for uterine peristalsis: A comparison of three different single shot fast spin echo techniques

Purpose To determine the optimal single shot fast spin echo (SSFSE) technique by varying interval between image acquisitions for cine MRI of uterine peristalsis. Materials and Methods MRI was performed in 13 premenopausal women (4 normal and 9 with benign pelvic pathology) in various phases of their menstrual cycle. Midsagittal uterus was scanned using a multiphasic SSFSE technique at 2-, 3-, and 4-s intervals over 2 min. Three readers independently and randomly evaluated for peristaltic frequency/2 min, longitudinal direction and intensity of peristalsis in three imaging parameters. Contrast-to-noise ratios (CNRs) were also obtained. Results Peristaltic frequency for the 2, 3, and 4 s was 2.2 ± 2.3, 3.3 ± 1.5, and 3.6 ± 1.3 waves/2 min, respectively. It increased by 1.5 (95% confidence interval [CI]: 0.31-2.64) waves/2 min with 4 s compared with 2 s. Direction was detected for the 2, 3, and 4 s in 5/13(38%), 9/13(69%) and 12/13(92%) women. Compared with 2 s, intensity of peristalsis in endometrial movement (P = 0.04), signal change of the JZ (P = 0.03), and spread into outer myometrium (P = 0.02), CNR _{endometrium-JZ} by 57% (P < 0.001), and CNR _{outer myometrium-JZ} by 45% (P < 0.01) increased with 4 s. Conclusion Cine MRI with SSFSE sequence for uterine peristaltism is best performed using a 4-s scan interval.