Uterine peristalsis and junctional zone: correlation with age and postmenopausal status.

Background Although age-related change of junctional zone (JZ) of the uterus has been known, there has been no previous systematic study of age-related changes of uterine peristalsis that is observed as the wave conduction of the thickest or darkest area within the JZ. Purpose To examine the age-related changes of uterine peristalsis in pre and postmenopausal women using cine magnetic resonance imaging (MRI), and to determine the correlation between peristalsis and JZ on T2-weighted (T2W) imaging. Material and Methods Cine MRI analysis was performed in 64 premenopausal volunteers and in 43 postmenopausal women. The peristaltic frequency, JZ detectability, and JZ thickness were evaluated and compared between the two groups. In the premenopausal group, the correlations between age and each item was examined. In the postmenopausal group, the number of years after menopause was used instead of age. The correlation between peristaltic frequency and JZ detectability or thickness was also analyzed. Results Peristaltic frequency and JZ detectability significantly differed between the two groups, while JZ thickness did not. Peristaltic frequency did not vary significantly with age before menopause and no peristalsis was observed after menopause. JZ detectability did not change significantly with age or number of years after menopause, while JZ thickness significantly increased with age before menopause, but did not vary after menopause. A significant moderate correlation was observed between JZ detectability and peristaltic frequency, but not between JZ thickness and peristaltic frequency. Conclusion Uterine peristalsis frequency did not change significantly according to age, but observed peristalsis on MRI significantly decreased after menopause.