Evaluating the diagnostic performance of an initial Transvaginal Sonogram (TVS) in patients with suspected ectopic pregnancy
Date of Award
Master of Medicine (MMed)
Imaging and Diagnostic Radiology (East Africa)
Purpose of the study: To evaluate the diagnostic performance of an initial transvaginal sonogram (TVS) in patients with suspected ectopic pregnancy (EP).
Objectives: 1) To determine the accuracy, sensitivity, specificity, positive and negative predictive values of an initial TVS scan in patients with suspected EP. 2) To determine the diagnostic utility of TVS findings as predictors of EP.
Methodology: This was a descriptive, prospective study of 131 consecutive mothers who had TVS for clinical suspicion of EP at the Aga Khan University hospital over a 12 month period between November 2007 and October 2008. The scans were performed in our radiology department by sonographers, residents and consultant radiologists. The mothers were followed-up to determine their clinical or surgical outcome, which was then used as a reference standard. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value for the initial TVS and sonographic predictors of EP were calculated. The study was approved by the University Research and Ethics Committee.
Results: The accuracy of an initial TVS in this study was 96% (126 / 131). Sensitivity, specificity, PPV and NPV of initial TVS was 84% (21 / 25), 99% (105 / 106), 95.5% (21 / 22) and 96.3% (105 / 109) respectively. The prevalence of EP in our study was 19.08 % (25 / 131). In this study, 69.4% (91/131) of mothers had intrauterine pregnancies while 10.4% of them were not gravid. Adnexal mass, hemoperitoneum and tubal ring sign had high specificities but low sensitivities. Presence of an extrauterine gestational sac with or without an embryo was associated with 100% specificity and PPV.
Conclusion: This study demonstrates that initial TVS is a highly accurate and reliable tool in the evaluation of mothers with clinical suspicion of ectopic pregnancy. With the high accuracy, specificity and predictive values more than 95% of mothers will be evaluated correctly.
Bett, Z. (2009). Evaluating the diagnostic performance of an initial Transvaginal Sonogram (TVS) in patients with suspected ectopic pregnancy (Unpublished master's dissertation). .