The role of three-dimensional MRI in the differentiation between angular pregnancy and interstitial pregnancy

Abstract

Background In clinical practice it is an ongoing challenge to distinguish between angular pregnancy and interstitial pregnancy. With the three-dimensional (3D) magnetic resonance imaging (MRI) being increasingly used, it is worth exploring its role in differentiating angular pregnancy from interstitial pregnancy. This study aims to investigate how 3D MRI can help reveal the differences between these two special pregnancies in the early diagnosis. Methods We reviewed and analyzed the 3D MRI images of 50 patients with interstitial pregnancy and 55 patients with angular pregnancy retrospectively. Imaging features were identified to compare these two special pregnancies, and the ROC (Receiver Operating Characteristic) analysis was conducted to assess the diagnostic performance. Results The significant differences of the 3D MRI imaging features between interstitial pregnancy and angular pregnancy were found in the outline of uterus cavity (p < 0.001), involvement of junctional zone (p < 0.001), the signal of surroundings (p = 0.005), the relationship with round ligament (p = 0.042), and the overlying myometrial thickness (p = 0.041). Furthermore, the multivariate logistic regression analysis identified a series of significant indicators for angular pregnancy, including the junctional zone involvement, being-surrounded by hyper/iso-intensity on 3D images, and the asymmetric outline of uterus cavity. Combining these three imaging features, the AUC (Area under the Curve) of ROC curve was 0.87 in distinguishing interstitial pregnancy from angular pregnancy. Conclusions This study suggests that 3D MRI can help distinguish angular pregnancy from interstitial pregnancy in clinical practice, with the advantages that conventional MRI or ultrasound does not have. Through the significant image features, 3D MRI plays an important role in improving the timing of diagnosis, avoiding unnecessary interventions, and preventing hemorrhage in clinical practice.

Interstitial Ectopic Pregnancy Associated With Painless and Severe Vaginal Bleeding: A Rare, Atypical Clinical Presentation

“…Furthermore, three-dimensional magnetic resonance imaging is considered to be of utmost help in differentiating interstitial ectopic pregnancy from angular pregnancy. In these cases, early diagnosis and avoidance of unnecessary interventions are crucial, contributing significantly to the prevention of hemorrhage and the reduction of morbidity and mortality [ 17 ]. Therefore, based on clinical findings, imaging results, and quantification of beta-chorionic gonadotropin hormone levels, the diagnosis of interstitial ectopic pregnancy can be established earlier and more accurately, providing the advantage of prompt treatment [ 18 ].…”

Distinguishing between cornual, angular and interstitial ectopic pregnancy: A case report and a brief literature review

“…If ultrasound findings are ambiguous or inconclusive, many authors recommend using MRI or, very rarely, a CT scan for such cases [ 19 , 37 , 38 ]. 3-D MRI has brought innovation to the diagnosis and distinction between angular and interstitial ectopic pregnancies [39] .…”

Ipsilateral Right Angular Pregnancy After a Laparoscopic Right Salpingo-Oophorectomy: A Case Report

“…An angular pregnancy implant is medial to the uterotubal junction, and it is possible to continue the pregnancy with careful observation [ 5 , 13 , 16 ]. In contrast, an interstitial pregnancy is implanted in the interstitial portion of the fallopian tube that lies in the uterine myometrium and has a high rate of maternal morbidity.…”

“…In this case, a GS was observed in the uterine cavity, and the chorionic sac was near the lateral edge of the uterine cavity, surrounded by a thick myometrial layer (> 5 mm) [ 19 ]. Furthermore, Jansen et al [ 16 ] suggested the following clinicosurgical criteria to define an angular pregnancy: (1) clinical presentation with painful asymmetric enlargement of the uterus; (2) direct observation (i.e., surgical) of lateral uterine distention with lateral displacement of the round ligament; and (3) retention of the placenta in the uterine angle. In our case, asymmetric enlargement of the uterus and displacement of the round ligament laterally are observed.…”