Do anticholinergic agents suppress uterine peristalsis and sporadic myometrial contractions at cine MR imaging?

PURPOSE

To prospectively evaluate anticholinergic drug effects on uterine peristalsis and sporadic myometrial contractions, as well as on intestinal motion, with cine magnetic resonance (MR) imaging.

MATERIALS AND METHODS

This prospective study was approved by the institutional review board; informed consent was obtained from all participants. Twenty-one women (mean age, 29.3 years +/- 4.0 [standard deviation]) underwent MR imaging during the follicular through periovulatory phases (cycle days 5-26). Before and after injection of an anticholinergic agent, 60 serial half-Fourier rapid acquisition with relaxation enhancement MR images were obtained within 2 minutes in the midsagittal uterine plane. Evaluations were performed independently and separately in random order by two radiologists who were blinded to whether an anticholingeric agent had been administered. Uterine peristalsis was evaluated for frequency (paired t test), predominant direction (McNemar test), degree of endometrial movement, wave conduction in the junctional zone (JZ), and wave conduction toward the outer myometrium (Wilcoxon signed rank test). Degree of sporadic contractions in the outer myometrium and intestinal motion were also evaluated (Wilcoxon signed rank test).

RESULTS

On postinjection images, uterine peristalsis decreased in frequency from 4.57 waves per 2 minutes +/- 1.62 to 3.52 waves per 2 minutes +/- 1.59, which is a 23% (95% confidence interval: 8.7%, 37.2%) average reduction (P = .003). There was no significant difference in actual predominant uterine peristalsis direction between pre- and postinjection images (P > .99). Although there were trends toward reduction of the degree of endometrial movement and of wave conduction in the JZ and toward the outer myometrium, these were not significant. The degree of sporadic myometrial contractions (P = .001) and intestinal motion (P < .001) decreased on postinjection images.

CONCLUSION

Anticholinergic agents significantly suppress sporadic myometrial contractions and uterine peristalsis, in addition to intestinal motion, all of which may contribute to improved quality of conventional uterine MR images.