MRI of the pelvic ring joints postpartum: normal and pathological findings.

PURPOSE

To assess the joints of the pelvic ring postpartum and to discern normal postpartum findings and pathologic lesions using MRI.

MATERIALS AND METHODS

MR images were obtained in six women with severe pelvic ring pain after delivery, in 13 women after uncomplicated vaginal delivery, and in 11 healthy, nulliparous non-pregnant volunteers. Distances of the pubic gap, signal intensities of the pubic cartilage, and signal changes of the pelvic ring bones were determined and evaluated.

RESULTS

Both postpartum groups had significantly larger distances of the interpubic gap compared to the nulliparous group (P = 0.0002). The mean signal intensity of cartilage of the symphysis pubis was significantly different on the T1-weighted and T2-weighted MR images in postpartum women compared to nulliparous women (P = 0.001), indicating a higher water content of the pubic cartilage. 13 of all 19 postpartum women had bruises of parasymphyseal pubic bones. One pubic symphysis rupture and one sacral stress fracture were detected in two symptomatic women.

CONCLUSION

MR imaging is a useful adjunct to clinical examination to identify patients with lesions of the pelvic ring postpartum. MRI of the pelvic ring of asymptomatic postpartum women can demonstrate signal changes of the pubic cartilage and small bruises of the pubic bones.