A comparison of pelvic ultrasound and magnetic resonance imaging as diagnostic studies for müllerian tract abnormalities

Abstract

Objective: The purpose of the present study was to compare prospectively the accuracy of pelvic US examination and MR imaging in the assessment of müllerian tract abnormalities.

Patients and methods: Sixteen patients with congenital müllerian defects underwent US examination, MR imaging, diagnostic laparoscopy, and hysteroscopy. Abnormalities included unicornuate (n = 2), bicornuate (n = 6), and septate (n = 6) uteri, and normal uteri with septate vagina (n = 2). Patients with müllerian abnormalities were referred after hysterosalpingogram or clinical examination revealed uterine, cervical, and/or vaginal congenital abnormalities. Laparoscopic and hysteroscopic confirmation of these radiologic impressions was made in all patients.

Results: Pelvic US examination and MR imaging for all abnormalities had an overall sensitivity of 57% and 77%, specificity of 50% and 33%, a positive predictive value of 89% and 83%, and a negative predictive value of 14% and 25%, respectively. Pelvic US examination and MR imaging correctly diagnosed septate uterus in 2/6 cases (33%) and 3/6 cases (50%), respectively. This abnormality was most commonly misdiagnosed as a normal or bicornuate uterine cavity. For bicornuate uterus, pelvic US and MR, however, correctly diagnosed 6/6 cases (100%) and 5/6 cases (83%), respectively. Accurate diagnoses were made for bicornuate uteri using either modality owing mainly to the presence of a characteristic fundal notch. US examination was nonspecific for unicornuate uterus (0/2 cases diagnosed), defining only a single cavity, but without sufficient details of adnexal regions. MR imaging of unicornuate uteri, however, provided detailed images of both uterine cavity configuration (2/2 cases diagnosed) and adnexal anatomy.

Conclusions: Our data suggest that pelvic US examination and MR imaging are not sufficiently accurate to qualify as sole diagnostic studies for septate uteri. Though less expensive and less invasive than diagnostic laparoscopy, they do not provide a sufficiently sensitive and specific method to differentiate septate from bicornuate uteri, a critical aspect for surgical planning. Though more costly, diagnostic laparoscopy appears to be the most accurate diagnostic study for the assessment of uterine anatomy and definition of müllerian abnormalities.