The frequency of the plicae palmatae in the uterine cervix on MR imaging

Background: The plicae palmatae is a developmental remnant of the Müllerian ductal fusion, which is demonstrated as a ridge of low intensity in the cervical canal on axial T2-weighted MR images. The identification of the plicae palmatae on MR imaging is beneficial for avoiding misinterpretation of this finding as anomalous uterine septum. The current study is performed to investigate the frequency of this finding and its variation among different age groups. Methods: Axial T2-weighted images in 433 subjects were evaluated regarding the presence of the plicae palmatae and uterine anomaly. Results: The frequency of the plicae palmatae was 47.5-53.2% in the third to fifth decade groups, but it was significantly lower in the sixth decade group (24.8%) than in the fifth decade group (53.2%). In three subjects with uterine anomalies, the plicae palmatae was recognized in a bicornuate uterus with single cervix, whereas it was not identified in unicornuate uterus and bicornuate uterus with duplicated cervices. Conclusion: The plicae palmatae is commonly encountered in routine MR images of normal uterus, especially in reproductive-aged women.