Diagnostic Accuracy of Preoperative Conventional MRI for Patients With Ectopic Pregnancy

Abstract

To assess the utility of preoperative magnetic resonance imaging (MRI) in the diagnosis of tubal pregnancy. Most cases of ectopic pregnancy are tubal pregnancies. Preoperative accurate diagnosis including the location of the tubal pregnancy is important. We performed a retrospective single-center cohort study evaluating patients who underwent surgery for ectopic pregnancy from April 2004 to March 2016 and who underwent preoperative MRI. Sixty patients were enrolled in the study. Chorion confirmed at the tubal pregnancy site detected by MRI was defined as a correct diagnosis. Mean estimated gestational age at the time of MRI according to the last menstrual period was 7 weeks (median: 5 weeks; range: 3–10 weeks). Ectopic pregnancy was diagnosed by MRI in 57 cases, and all cases were either left or right tubal pregnancy. In 52 cases, the actual position matched the MRI findings. In 5 cases, the location of tubal ectopic pregnancy was different from that diagnosed by MRI, or no tubal pregnancy was observed intraoperatively. In 2 cases, no ectopic pregnancy site was observed on MRI, but tubal pregnancy was confirmed by surgery. In one case, an ectopic pregnancy site was not found, and the tube showed normal findings on MRI. The sensitivity of MRI diagnosis was 96.2%, specificity was 16.7%, positive predictive value was 91.1%, and negative predictive value was 33.3%. In cases of ectopic pregnancy treated surgically, the sensitivity of MRI diagnosis, including identification of the location of ectopic pregnancy, is high.