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

Abstract

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