MR imaging of ectopic pregnancy with an emphasis on unusual implantation sites

Common and Uncommon Gestational Complications in Radiological Practice: An Overview

Gestational complications are common in radiological practice and can be identified and evaluated using various imaging methods. Each complication typically presents with specific imaging features; however, there is a lack of comprehensive literature that consolidates this information to facilitate a diagnostic algorithm and focused study. In this context, this review aims to revisit the theoretical basis of differentials in pregnancy-related complications, discussing classic imaging features and providing examples of key features for each diagnosis. The focus is on essential information for accurate diagnosis, emphasizing the role of radiologists in contributing to better outcomes.

Unruptured ovarian ectopic pregnancy: Two case reports and literature review

In clinical practice, ovarian pregnancy is extremely rare and is always found to be ruptured. A definitive diagnosis for ruptured ovarian pregnancy is difficult to obtain. We present two cases of unruptured ovarian pregnancies detected during laparoscopy and review existing literature to better understand the clinical characteristics of ectopic pregnancies in this rare site. Intrauterine devices, assisted reproductive technology, and intrauterine operations are all high-risk factors in ovarian pregnancy. Moreover, menopause, abdominal pain, and vaginal bleeding are clinical manifestations. Ovarian pregnancy can be diagnosed using serum hCG, transvaginal ultrasound, and magnetic resonance imaging. Laparoscopy is the treatment of choice for ovarian pregnancy. It is recommended that the intact gestational sac be excised and the ovarian function be protected to the greatest extent possible during the operation. More definitive diagnosis of ovarian pregnancy must be reported in order to gain a better understanding of ovarian pregnancy.

Using MRI to differentiate upper-lateral intracavitary pregnancy and interstitial pregnancy for the patients with pregnancies in the uterotubal junction during the first trimester

Objectives

To retrospectively evaluate the diagnostic value of MRI for the uterotubal junctional pregnancies during the first trimester.

Methods

This retrospective study involved 59 patients (January 2016 to July 2021) with a preoperative imaging diagnosis of uterotubal junctional pregnancy. Using operative and pathological reports as the reference standard, we identified 22 patients with upper-lateral intracavitary (angular) pregnancy and 37 patients with interstitial pregnancy. Two senior radiologists, blinded to the patients’ information, reviewed the MRI images and determined each MRI feature based on the original interpretation criteria. Any disagreement was resolved by discussion to achieve a consensus. The sensitivity and specificity of each MRI feature were calculated according to the reference standard.

Results

The endometrial thickness in the upper-lateral intracavitary pregnancy group was larger than in the interstitial group (p = 0.001). The cutoff value of the endometrial thickness was 11.5 mm with a sensitivity, specificity, and area under the curve that were 77.3%, 64.9%, and 0.743, respectively. Two key features to diagnose upper-lateral intracavitary pregnancy were “medial free edge” and “medial free edge plus above-cutoff endometrial thickness.” The sensitivity and specificity of the medial free edge were 100% and 94.9%, respectively. The sensitivity and specificity of the medial free edge plus above-cutoff endometrial thickness were 77.3% and 100%, respectively. The key feature to diagnose interstitial pregnancy was an “intact lateral junctional zone,” of which the sensitivity and specificity were 94.6% and 100%, respectively.

Conclusions

MRI can be used to differentiate the upper-lateral intracavitary pregnancy and interstitial pregnancy during the first trimester.

Key Points

• We demonstrated MRI diagnostic criteria for the interstitial pregnancy and upper-lateral intracavitary pregnancy.

• MRI might be used to identify the complex interstitial pregnancies, those with a gestational sac protruding into the uterine cavity.

Definition and sonographic reporting system for Cesarean scar pregnancy in early gestation: modified Delphi method

OBJECTIVE

To develop a standardized sonographic evaluation and reporting system for Cesarean scar pregnancy (CSP) in the first trimester, for use by both general gynecology and expert clinics.

METHODS

A modified Delphi procedure was carried out, in which 28 international experts in obstetric and gynecological ultrasonography were invited to participate. Extensive experience in the use of ultrasound to evaluate Cesarean section (CS) scars in early pregnancy and/or publications concerning CSP or niche evaluation was required to participate. Relevant items for the detection and evaluation of CSP were determined based on the results of a literature search. Consensus was predefined as a level of agreement of at least 70% for each item, and a minimum of three Delphi rounds were planned (two online questionnaires and one group meeting).

RESULTS

Sixteen experts participated in the Delphi study and four Delphi rounds were performed. In total, 58 items were determined to be relevant. We differentiated between basic measurements to be performed in general practice and advanced measurements for expert centers or for research purposes. The panel also formulated advice on indications for referral to an expert clinic. Consensus was reached for all 58 items on the definition, terminology, relevant items for evaluation and reporting of CSP. It was recommended that the first CS scar evaluation to determine the location of the pregnancy should be performed at 6-7 weeks' gestation using transvaginal ultrasound. The use of magnetic resonance imaging was not considered to add value in the diagnosis of CSP. A CSP was defined as a pregnancy with implantation in, or in close contact with, the niche. The experts agreed that a CSP can occur only when a niche is present and not in relation to a healed CS scar. Relevant sonographic items to record included gestational sac (GS) size, vascularity, location in relation to the uterine vessels, thickness of the residual myometrium and location of the pregnancy in relation to the uterine cavity and serosa. According to its location, a CSP can be classified as: (1) CSP in which the largest part of the GS protrudes towards the uterine cavity; (2) CSP in which the largest part of the GS is embedded in the myometrium but does not cross the serosal contour; and (3) CSP in which the GS is partially located beyond the outer contour of the cervix or uterus. The type of CSP may change with advancing gestation. Future studies are needed to validate this reporting system and the value of the different CSP types.

CONCLUSION

Consensus was achieved among experts regarding the sonographic evaluation and reporting of CSP in the first trimester. © 2021 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Magnetic Resonance Imaging Evaluation of Ectopic Pregnancy: A Value-Added Review

ABSTRACT

Ectopic pregnancy (EP) is a known cause of maternal mortality and may be misdiagnosed in up to 50% of pregnant female individuals (Ann Emerg Med. 1996;28(1):10-17). Magnetic resonance imaging, with its superior soft tissue resolution, is a valuable alternative diagnostic modality to diagnose EP when transvaginal ultrasound results are inconclusive. Although an extrauterine gestational sac is the most specific finding, there are other key MRI findings that can aid in diagnosing EP. As availability of MRI access in the emergency department setting increases across the nation, its utility in women with a positive pregnancy test has also increased. Specific MRI findings that are diagnostic of EP include absence of intrauterine pregnancy, adnexal mass separate from the ovary, and hemoperitoneum. In addition, intrauterine ectopic locations, especially intramural, cornual, and cervical pregnancies, can be diagnosed with increased accuracy with the help of MRI. Magnetic resonance imaging is also useful in excluding potential mimics of EP, including adnexal cysts, ovarian neoplasms, and fibroids. In summary, providing an accurate diagnosis and determining the precise location of an EP, which is supported by the use of MRI, is imperative for guiding a patient's treatment to prevent a potentially fatal outcome.

A rare case of heterotopic pregnancy after a single embryo transfer: A case report and literature review

Heterotopic pregnancy (HP) is a rare but life-threatening disease. We report a rare case of HP that occurred after single embryo transfer (SET) with spontaneous natural pregnancy possibly due to sexual intercourse (SI) during assisted reproductive technology treatment and reviewed previous reports. A 39-year-old woman at 7 weeks 5 days' gestation with anti-sperm antibody who underwent a single frozen-thawed embryo transfer in her natural cycle presented with lower abdominal pain and vaginal bleeding. She had several SIs before the day of SET. A viable intrauterine fetus and an extrauterine mass at the right adnexa were detected on transvaginal ultrasonography. An emergent laparoscopic surgery showed a swollen right fallopian tube, and right salpingectomy was performed. Unfortunately, intrauterine fetal death was diagnosed at 19 weeks' gestation. In conclusion, the possibility of HP should be considered in patients with SIs around the day of SET.

Use of Magnetic Resonance Imaging (MRI) in the Management of Diagnostic Uncertainty in Low-Resource Settings: A Case Report of Cesarean Ectopic Pregnancy in a Tertiary Hospital in Ghana

Patient: Female, 35-year-old

Final Diagnosis: Cesarean section ectopic pregnancy

Symptoms: Amenorrhea

Medication:—

Clinical Procedure: Exploratory laparotomy • MRI • ultrasonography

Specialty: Obstetrics and Gynecology

Magnetic resonance imaging of common, uncommon, and rare implantation sites in ectopic pregnancy

OBJECTIVE

To review the MRI appearances of tubal and non-tubal implantation sites in ectopic pregnancy.

CONCLUSION

Transvaginal ultrasound is the primary imaging modality in ectopic pregnancy and MRI is used as a problem-solving tool in selected indications as detailed in the article. MRI features of tubal, interstitial, cervical, cesarean scar, cornual, ovarian, abdominal, and heterotopic pregnancies are provided to familiarize the radiologists with their appearances thereby assisting them in making early and accurate diagnosis.

Clinical significance of expression of hsa-mir-1247 and hsa-mir-1269a in ectopic pregnancy due to salpingitis

The clinical significance of hsa-mir-1247 and hsa-mir-1269a expression in ectopic pregnancy due to salpingitis was investigated. Eighty patients with ectopic pregnancy diagnosed by ultrasonography who were admitted to Jinan Maternity and Child Care Hospital from January 2012 to May 2012 were enrolled in this study. To the observation group were assigned 35 patients whose ectopic pregnancy was due to salpingitis. The remaining 45 patients whose ectopic pregnancy was due to reasons other than endometriosis were assigned to the control group. Moreover, 32 healthy pregnant women were enrolled in this study at the same time as the healthy control group. Compared with the healthy control group, hsa-mir-1247 and hsa-mir-1269a were downregulated and upregulated, respectively, in patients with ectopic pregnancy (P<0.05). The difference was even more marked in patients with ectopic pregnancy due to salpingitis (P<0.05). The expression levels of hsa-mir-1247 and hsa-mir-1269a were negatively correlated, and the correlation coefficient r and P-value was -0.667 and 0.006, respectively. Abnormal expression of hsa-mir-1247 and hsa-mir-1269a may be risk factors for ectopic pregnancy. Abnormal expression of hsa-mir-1247 and hsa-mir-1269a found in patients with ectopic pregnancy due to salpingitis may be used as biomarkers of ectopic pregnancy.

MRI findings of complications related to previous uterine scars

Although the World Health Organization suggests 10–15% as the adequate cesarean delivery rate to assure optimal prognosis for mother and children, cesarean rates have continuously increased worldwide over the last three decades, even in primiparous women. Moreover, uterine scars after myomectomies, complications of obstetrical interventions and more recently, after fetal surgery, are often observed. This review article describes the most commonly seen complications related to prior uterine scars and discusses their imaging findings, with emphasis on the increasing role of Magnetic Resonance Imaging for diagnosis.

To evaluate the feasibility of magnetic resonance imaging in predicting unusual site ectopic pregnancy: a retrospective cohort study

OBJECTIVE

To evaluate the accuracy of pelvic MRI in the diagnosis of unusual ectopic pregnancy (EP), when ultrasound (US) examination is inconclusive.

METHODS

We retrospectively reviewed the medical records of 150 patients with suspected EP. Clinical, US and MRI features of 15 unusual EPs were analysed. Two radiologists independently reviewed each case resolving by consensus any diagnostic discrepancy. Interobserver agreement was assessed using the Cohen κ test.

RESULTS

MRI displayed a gestational sac-like structure surrounded by a thick wall in all cases. The thick wall displayed hyperintensity in 41 %, isointensity in 35 % and hypointensity in 24 % of cases on T1-weighted images. Diffusion- and fat saturation T1-weighted images were the most accurate sequences, as they enabled identification of 15/15 and 14/15 patients, respectively. Although US was false negative in detecting cervical and uterine infiltration underlying the caesarean scar, MRI was able to identify the invasion. Interobserver agreement was very good for all sequences (κ=0.892-1.0).

CONCLUSIONS

MRI plays an important role in the early diagnosis of unusual EP. It should be considered after negative US findings, providing accurate evaluation of the site and the possible infiltration of these lesions, which help in the management of these patients.

KEY POINTS

• MRI is being increasingly used as a problem-solving modality in ectopic pregnancy. • MRI plays an important role in early diagnosis of unusual ectopic pregnancy. • Knowledge of MRI features in EP is essential to determinate appropriate management.

Curettage after uterine artery embolization combined with methotrexate treatment for caesarean scar pregnancy

In the present study, we evaluated the diagnosis and management modalities of caesarean scar pregnancy (CSP). Thirty patients diagnosed with CSP were retrospectively studied between February, 2010 and February, 2012. Twenty-five patients were offered prophylactic uterine artery embolization (UAE) and methotrexate (MTX) prior to uterine suction curettage. Five cases were referred from other hospitals where the initial management with uterine suction curettage had resulted in uncontrollable massive haemorrhage, 4 of the cases had UAE and one proceeded immediately to hysterectomy. In the 25 patients treated with prophylactic UAE and MTX, 12 had laparoscopy-guided curettage and 13 had ultrasound-guided curettage without complication. The results showed that the 25 patients with CSP, who received prophylactic UAE and MTX prior to uterine curettage, recovered without complications. Five patients referred from other hospitals, where uterine curettage was the primary procedure, had severe complications including uncontrolled vaginal bleeding and uterine rupture. Four of the five patients were treated successfully with emergency UAE and the remaining patient underwent emergency hysterectomy as ultrasound examination detected significant haemorrhage between the uterus and the bladder. Of the 25 patients who received prophylactic UAE combined with MTX, there were no reports of irregular menstruation or serious adverse effects. Notably, the decrease in serum human chorionic gonadotropin (HCG) levels 3 days post-surgery was greater with ultrasound-guided curettage (84.3±5.5%) than with laparoscopy-guided curettage (76.3±10.2%). In summary, the data suggested that prophylactic UAE with MTX followed by ultrasound-guided curettage is the most effective therapeutic approach in CSP.

A Case of Ovarian Pregnancy Diagnosed by MRI

Ovarian pregnancy is a rare form of ectopic pregnancy, causing a great diagnostic challenge. We report a case of ovarian pregnancy in a 42-year-old woman, in whom MRI successfully demonstrated the implantation in the ovary. Transvaginal ultrasonography showed an echogenic mass in the right ovary but failed to demonstrate tubal pregnancy. T2-weighted MR images disclosed a gestational sac structure in the right ovary, which exhibited heterogeneous high intensity intermingled with punctate foci of distinct low intensity. MRI may be a useful tool for diagnosing ovarian pregnancy, by demonstrating a gestational sac in the ovary.

Uncommon Implantation Sites of Ectopic Pregnancy: Thinking beyond the Complex Adnexal Mass

Ectopic pregnancy occurs when implantation of the blastocyst takes place in a site other than the endometrium of the uterine cavity. Uncommon implantation sites of ectopic pregnancy include the cervix, interstitial segment of the fallopian tube, scar from a prior cesarean delivery, uterine myometrium, ovary, and peritoneal cavity. Heterotopic and twin ectopic pregnancies are other rare manifestations. Ultrasonography (US) plays a central role in diagnosis of uncommon ectopic pregnancies. US features of an interstitial ectopic pregnancy include an echogenic interstitial line and abnormal bulging of the myometrial contour. A gestational sac that is located below the internal os of the cervix and that contains an embryo with a fetal heartbeat is indicative of a cervical ectopic pregnancy. In a cesarean scar ectopic pregnancy, the gestational sac is implanted in the anterior lower uterine segment at the site of the cesarean scar, with thinning of the myometrium seen anterior to the gestational sac. An intramural gestational sac implants in the uterine myometrium, separate from the uterine cavity and fallopian tubes. In an ovarian ectopic pregnancy, a gestational sac with a thick hyperechoic circumferential rim is located in or on the ovarian parenchyma. An intraperitoneal gestational sac is present in an abdominal ectopic pregnancy. Intra- and extrauterine gestational sacs are seen in a heterotopic pregnancy. Two adnexal heartbeats suggest a live twin ectopic pregnancy. Recognition of the specific US features will help radiologists diagnose these uncommon types of ectopic pregnancy.