Value of transvaginal ultrasound in assessing severity of pelvic endometriosis

The objective of this study was to examine the ability of preoperative transvaginal ultrasound (TVS) scanning to assess the severity of pelvic endometriosis.

Consecutive women with clinically suspected or proven pelvic endometriosis, who were booked for laparoscopy, were invited to join the study. The severity of endometriosis was assessed preoperatively using TVS and the findings were compared with the results obtained by laparoscopy using the American Society for Reproductive Medicine (ASRM) classification.

In total, 201 women had preoperative TVS and laparoscopies. Of these, no endometriosis was found at laparoscopy for 62/201 (30.8%; 95% CI, 24.8-37.5), whereas 33/201 (16.4%; 95% CI, 11.9-22.2) had minimal endometriosis, 31/201 (15.4%; 95% CI, 11.1-21.1) had mild endometriosis, 27/201 (13.4%; 95% CI, 9.4-18.8) had moderate endometriosis and 48/201 (23.9%; 95% CI, 18.5-30.2) had severe endometriosis. The sensitivity and specificity of the TVS diagnosis of severe pelvic endometriosis were 0.85 (95% CI, 0.716-0.934) and 0.98 (95% CI, 0.939-0.994), respectively, and the positive and negative likelihood ratios were 43.5 (95% CI, 14.1-134) and 0.15 (95% CI, 0.075-0.295), respectively. Overall, there was a good level of agreement between ultrasound and laparoscopy in identifying absent, minimal, mild, moderate and severe disease (quadratic weighted kappa = 0.786). The mean ASRM score difference between TVS and laparoscopy in assessing severity of endometriosis was -2.398 (95% CI, -4.685 to -0.1112) and the limits of agreement were -34.62 (95% CI, -38.54 to -30.709) to 29.83 (95% CI, 25.91-33.74).

TVS is a good test for assessing the severity of pelvic endometriosis. TVS is particularly accurate in detecting severe disease, which could facilitate more effective triaging of women for appropriate surgical care.