Diagnostic accuracy of transvaginal ultrasound in detecting free pelvic fluid.

OBJECTIVE

To evaluate the diagnostic accuracy of transvaginal ultrasonography in detecting and measuring free pelvic fluid.

STUDY DESIGN

Eighty-two patients undergoing diagnostic or therapeutic laparoscopy at a tertiary care center were prospectively assessed before surgery by transvaginal ultrasound. Free pelvic fluid was measured in two ultrasonographic planes. These measurements were compared to the volume of fluid aspirated during laparoscopy.

RESULTS

The mean volumes reported for transvaginal ultrasound were significantly lower than those observed at laparoscopy (mean milliliters +/- SEM, 2.54 +/- 0.5 versus 9.42 +/- 1.3, P < .001). The smallest volume of free pelvic fluid that was consistently detected by ultrasound was 8 mL. Whenever no fluid or < 1 mL was detected by transvaginal ultrasound, a small volume of fluid was found at laparoscopy (mean milliliters +/- SEM, 1.6 +/- 0.47). The sensitivity of transvaginal ultrasound was 83% and specificity was 69%.

CONCLUSION

Transvaginal ultrasound is a sensitive method of detecting the presence of > 8 mL of free pelvic fluid and therefore is an important diagnostic tool in the assessment of pelvic pathology associated with increased peritoneal fluid.