MRI Findings in Patients Considered High Risk for Pelvic Floor Injury Studied Serially After Vaginal Childbirth

OBJECTIVE. The purpose of this article is to characterize pelvic floor injury after vaginal childbirth with serial MRI. SUBJECTS AND METHODS. MR images (3-T) were obtained early (1 month) and late (7 months) after first childbirth in 19 women with risk factors for pelvic floor injury. All women underwent multiplanar intermediate-weighted sequences, and 11 women underwent fluid-sensitive sequences. MR images were evaluated for levator edema and tears and for pubic abnormalities. RESULTS. Three women had unilateral high-grade tears, three had unilateral low-grade tears, and one had bilateral high-and low-grade tears of the levator ani muscles. All tears were focal at the pubis. Levator edema was present in all women on initial imaging and was resolved at follow-up. Six women had bone marrow edema, five with fracture line. None showed a pattern indicating nerve damage separate from muscle tears. CONCLUSION. MRI showed focal levator ani muscle tears at the pubis with bone marrow edema and fracture in patients at risk for pelvic floor injury.