Anticholinergic agents result in weaker and shorter suppression of uterine contractility compared with intestinal motion: time course observation with cine MRI

PURPOSE: To evaluate the time course effects of anticholinergic agents on uterine contractility and intestinal motion with cine magnetic resonance imaging (MRI). MATERIALS AND METHODS: Using a 1.5 T MRI scanner, 60 T2-weighted half-Fourier rapid acquisitions with relaxation enhancement images of the uterus were serially acquired over 3 minutes in 25 healthy women in the periovulatory phase, at four instances, prior to and 2-5, 5-8, and 10-13 minutes after intravenous injection of 20 mg of hyoscine butylbromide. Uterine peristalsis frequency (waves / 3 min) and degrees of endometrial transformation, subendometrial conduction, outer myometrial conduction, sporadic myometrial contraction, and intestinal movement were independently evaluated by three readers. RESULTS: Uterine peristalsis frequency of 6.14 ± 2.34 decreased the most at 2-5 minutes (P < 0.001) by 1.41 (95% confidential interval [CI] = 0.59-2.22), or 23.0% ([6.14-4.73]/6.14) and remained reduced at 5-8 minutes (P = 0.013) by 0.97 (95% CI = 0.15-1.78), or 15.8% ([6.14-5.17]/6.14) after injection. The degree of intestinal movement was 3.32 ± 0.54 and was prominently reduced at every phase (P < 0.001 for all) and maximally decreased to 0.67 ± 0.65 at 5-8 min. It increased to 1.36 ± 0.72 at 10-13 minutes compared with the degrees of motion at 2-5 minutes (P = 0.04) and 5-8 minutes (P = 0.004). CONCLUSION: Suppression of uterine peristalsis was weaker and shorter compared with the stronger and longer suppression of intestinal movement by the intravenous administration of anticholinergic agents.