Transvaginal sonographic features in diagnosis of ectopic pregnancy

To evaluate the efficacy of pelvic transvaginal sonography (TVS) in patients with clinical presentation of extrauterine pregnancy (EUP) and positive beta-hCG.

Three hundred and twenty-one patients with clinical suspicion of EUP were subjected to TVS at Maharaj Nakorn Chiang Mai Hospital. The criteria for entry to the study were (1) clinical suspicion of EUP, with stable hemodynamic condition, (2) correct final diagnosis must be known, (3) serum beta-hCG must be determined, by assay sensitivity of 10 mIU/ml (4) TVS was examined by the same sonographer. Frequencies of each TVS feature in EUP and IUP were determined. Among the patients with positive beta-hCG and empty uterus, the accuracy indices of various TVS features in predicting EUP were calculated.

Patients with measurable beta-hCG were divided into two main groups, namely those with demonstrable typical intrauterine gestational sac (52/201), and those without (149/201). None of the subjects in the first group had EUP. Among the latter group of patients, with empty uterus, TVS signs could be further divided into 3 subgroups: (1) Direct sign, clear evidence of extrauterine gestational sac. This group had positive predictive value 100%, but low sensitivity (26%). (2) Indirect signs of EUP, i.e. adnexal mass and pelvic fluid, especially echogenic fluid. Echogenic fluid, adnexal mass and their combination had positive predictive value for EUP 92.3%, 92.8% and 95.0%, respectively. Complex adnexal mass gave the highest sensitivity (85.7%). (3) No positive sign on TVS, which is very unlikely to be EUP, and was found in only 2.8% of EUP.

The results of this study indicate that TVS can help to facilitate the diagnosis of EUP in most cases. EUP can be confidently diagnosed by demonstration of adnexal ring, and excluded by visualization of intrauterine sac. Complex adnexal mass and echogenic fluid are extremely helpful in making the diagnosis.