First trimester caesarean scar ectopic pregnancy evaluation using MRI

Abstract

To determine the features of caesarean scar ectopic pregnancy (CSP) by using magnetic resonance imaging (MRI) in the first trimester. Thirty-nine women with CSP in the first trimester were initially selected and underwent transvaginal ultrasound and MRI examinations. Thirty-five patients with CSP were finally included in this study. The CSPs were categorized into three groups: type I, in which a thin-walled diverticulum is present at the caesarean section scar (CSS) defect and the gestational sac (GS) is embedded in the diverticulum; type II, in which a thin-walled diverticulum is present at the CSS defect and the GS is partially embedded in the diverticulum; type III, in which a niche is present in the CSS defect and the GS is mainly embedded in the isthmus. Types I, II, and III CSP occurred in 40, 46, and 14% of the women, respectively. There was no significant difference between the three types in the minimum thickness of the CSS defect. In types I and II, there was a positive correlation in the maximum inlet diameter of the CSS defect and the approximate area of the GS. Using MRI, most CSPs present as a diverticulum at the CSS defect, and the CSS defect becomes weaker with the growth of the GS. MRI showed detailed features of the CSP.