Ultrasonography and magnetic resonance imaging findings in a patient with an unruptured interstitial pregnancy

Sonographic diagnosis of an interstitial pregnancy in an asymptomatic patient at 7 weeks' gestation

An interstitial pregnancy is an ectopic pregnancy located within the proximal intramural segment of the Fallopian tube traversing the myometrium. This type of ectopic pregnancy is relatively rare, occurring in approximately 1%-3% of all ectopic pregnancies. Given the myometrial mantle surrounding the gestational sac, which is considerably thicker than in other tubal pregnancies, patients with interstitial pregnancies classically manifest symptoms later in gestation. Thus, there is an increased risk of life-threatening intraperitoneal hemorrhage upon rupture of the myometrium encompassing the pregnancy. We present an unusual case of early sonographic diagnosis of an interstitial pregnancy in an asymptomatic patient at 7 and 3/7 weeks’ gestation, discuss predisposing factors, hallmarks of sonographic diagnosis, and review the literature regarding available clinical management modalities. With the increasing application of point of care ultrasound (POCUS) by emergency room physicians and other providers in outpatient facilities, our case emphasizes both the importance of correct sonographic identification of interstitial pregnancy and the clinical importance of uniform early first-trimester sonography, preferably no later than 7-8 weeks’ gestation.

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.

Use of magnetic resonance analysis for clinical evaluation of the peripheral area of gestational sac in bleeding and non-bleeding ectopic pregnancy cases

Purpose

To evaluate preoperative magnetic resonance (MR) imaging features of bleeding and non-bleeding ectopic pregnancy (EP) by comparison with surgical findings.

Methods

Eighteen suspected EP cases underwent preoperative MR imaging. We classified 8 cases as the bleeding group and 7 cases as the non-bleeding group with or without intra-abdominal bleeding and/or hematoma at the site of EP, and compared, retrospectively, gestational sac (GS)-like structure, particularly the peripheral area of the GS via MR analysis. Excluded were 3 cases that were insufficient for assessing extrauterine GS-like structure: ruptured tubal pregnancy and uterine horn pregnancy.

Results

GS-like structures were typically observed as low intensity on T1-weighted image (T1WI) and as high intensity on T2-weighted image (T2WI). In non-bleeding cases, most peripheral areas of the GS were of intermediate intensity on T1WI and high intensity on T2WI. Most bleeding cases were of high intensity on T1WI and low to high intensity on T2WI. Furthermore, the peripheral area of the GS was of higher intensity on T1WI with fat suppression than on T1WI.

Conclusions

It is clear that MR imaging is effective for diagnosis of cases of suspected EP. EP conditions may be predicted by signal intensity of the peripheral area of the GS via MR analysis.

Ruptured heterotopic interstitial pregnancy: rare case of acute abdomen in a Jehovah's Witness patient

OBJECTIVE

To report a case of ruptured right heterotopic interstitial pregnancy diagnosed and managed laparoscopically by cornual resection.

DESIGN

Case report.

SETTING

University tertiary care hospital.

PATIENT(S)

A 29-year-old female Jehovah's Witness patient with first-trimester acute right lower quadrant abdominal pain.

INTERVENTION(S)

Emergency laparoscopy was performed, and the site of bleeding was first clamped with a laparoscopic grasper. The lateral tissue was then coagulated and simultaneously transected with the bipolar-cutting probe for control of hemorrhage.

MAIN OUTCOME MEASURE(S)

The early diagnosis of heterotopic interstitial pregnancy should enable a conservative approach, whether medical or surgical, to be undertaken when treating this rare and potentially fatal condition.

RESULT(S)

The treatment of a ruptured heterotopic interstitial pregnancy by laparoscopy was successful with cornual resection.

CONCLUSION(S)

Management of a ruptured interstitial pregnancy by laparoscopy was successful with cornual resection and minimal blood loss, and a coexiting intrauterine pregnancy continued satisfactorily.

MR features of ectopic pregnancy

Ectopic pregnancy (EP), in which a fertilized ovum implants outside the uterine cavity, is the leading cause of pregnancy-related death in the first trimester. EP is usually suspected by a positive pregnancy test and an empty uterus on transvaginal sonography (TVS). Although TVS is the initial modality of choice, it may occasionally fail to demonstrate the implantation site. When TVS findings are indeterminate, magnetic resonance imaging (MRI) may provide better delineation of the focus of EP owing to its excellent tissue contrast. The key MRI features of EP include gestational sac (GS)-like structures that typically appear as a cystic sac-like structure, frequently associated with surrounding acute hematoma of distinct low intensity on T2-weighted images. In tubal pregnancy, an enhanced tubal wall on postcontrast images may be another diagnostic finding. Ruptured EP is inevitably associated with acute hematoma outside these structures. In intrauterine EP, recognition of the relationship between GS-like structure and the myometrium can aid in differentiating from normal pregnancy. Diagnostic pitfalls include heterotopic pregnancy, decidual changes in endometrial cyst and theca lutein cysts mimicking GS-like structures. Knowledge of a spectrum of clinical and MRI features of EP is essential for establishing an accurate diagnosis and determining appropriate management.

Diagnosis of Ectopic Pregnancy with MRI: Efficacy of T2*-weighted Imaging

PURPOSE

To assess MRI in diagnosing ectopic pregnancy (EP), emphasizing T(2)*-weighted imaging (WI) efficacy.

METHODS AND MATERIALS

This is a prospective study of 24 female patients (16 to 41 years, average 29.9) clinically suspected of EP from April 1999 to June 2001. Eighteen had minimal vaginal bleeding and slight abdominal pain. All had positive pregnancy tests, and sonography showed no intrauterine pregnancy despite estimated gestational age of embryos and/or high concentrations of human chorionic gonadotrophin. MRI was performed with a 1.5T imager (Siemens, Vision VB33A) with a body-array coil. T(2)-WI (HASTE), T(1)-WI (2D FLASH), and T(2)*-WI (2D FLASH) were obtained without contrast. T(2)-WI was routinely obtained in 3 directions. T(2)*-WI orientation was determined based on the T(2)-WI. One of 4 radiologists with experience interpreting abdominal MR images interpreted images based on transvaginal ultrasonography (TVUS) and laboratory results. Abnormal adnexal mass with remarkable low signal area on T(2)*-WI was diagnosed as EP.

RESULTS

We diagnosed 19 cases as EP. Tubectomy in eighteen and abdominal total hysterectomy in one confirmed diagnosis. In one undergoing diagnostic laparoscopy, EP was denied. In 5 cases diagnosed negative based on the above criterion, no mass was detected in three, and no area of low signal was recognized on T(2)*-WI in the masses in two. EP was denied in four of five, and in one of the five, who underwent tubectomy, EP without bleeding was diagnosed. All EP were tubal pregnancies at final diagnosis, 19 were ampullar pregnancies and one, interstitial. Using MRI to diagnose EP, with T(2)*-WI as a key diagnostic factor, sensitivity was 95%, specificity 100%, and accuracy 96%.

CONCLUSIONS

MRI using T(2)*-WI is a sensitive, specific, and accurate method to evaluate EP. T(2)*-WI is highly accurate for detecting and diagnosing EP because of its sensitivity to fresh hematoma.

Evaluation of ectopic pregnancy by magnetic resonance imaging

Patients (n = 37) suspected of ectopic pregnancy were prospectively evaluated with magnetic resonance (MR) imaging to assess the capability of MR imaging in the diagnosis of ectopic pregnancy. Five levels of confidence were defined: diagnostic, suspicious, equivocal, questionable, and negative. Tubal wall enhancement and presence of tubal haematoma or gestational sac-like structure were considered diagnostic findings. There were 21 diagnostic, two suspicious, eight equivocal, and six negative findings. MR findings were compared with the surgical findings in 18 patients. Surgical confirmation was obtained in 12 diagnostic, two suspicious, and four equivocal studies. Using the MR diagnostic criteria for tubal pregnancy, MR had 12 true positive, three true negative, three false negative, and no false positive results for the diagnosis of tubal pregnancy. Retrospective analysis of the signal intensity of haematoma and ascites was performed for these 18 surgically confirmed cases. The predominant signal intensity of tubal haematoma was an intermediate signal on T1-weighted image (WI) and a low signal on T2WI. Ascites showed signal intensity higher than that of urine on T1WI in 100% of 13 cases. In conclusion, MR imaging with use of intravenous contrast material allows a specific diagnosis of tubal pregnancy, recognizing tubal wall enhancement and fresh tubal haematoma.