Role of transvaginal sonography in the diagnosis of peritoneal inclusion cysts

OBJECTIVE: The aim of this prospective study was to investigate the accuracy of B-mode transvaginal sonography alone and combined with color Doppler imaging and cancer antigen 125 (CA 125) plasma concentrations in differentiating peritoneal cysts from other adnexal masses. METHODS: Between September 1999 and September 2003, 213 adnexal masses underwent transvaginal sonography combined with power Doppler evaluation. Plasma concentrations of CA 125 were measured before surgery. The sonographic suspicion of peritoneal cysts (the presence of a bizarre lump-shaped cyst with a thin wall and fine internal septations with or without an ovary suspended among adhesions) was then compared with the surgical diagnosis. The overall agreement between the sonographic test results and the surgical findings was calculated by the kappa index. The diagnostic value of each test was also evaluated with likelihood ratios (LRs). RESULTS: Thirteen of 213 patients were found to have peritoneal cysts. Specificity and sensitivity of B-mode sonography for differentiating peritoneal cysts from other adnexal masses were 96% (95% confidence interval, 94%-97%) and 62% (95% confidence interval, 35%-83%), respectively. The value of the negative LR (0.40) indicated a good clinical test, whereas the positive LR (15) indicated an excellent test. Power Doppler imaging did not seem to increase the accuracy of B-mode transvaginal sonography (kappa = 0.51 and 0.52, respectively), nor did the association of CA 125 plasma concentration (kappa = 0.34). CONCLUSIONS: Transvaginal sonography alone is a useful method for detection of peritoneal cysts