Visualization of free peritoneal fluid with transvaginal sonography. A preliminary study

Visualization of free peritoneal fluid during sonographic examination is often of considerable clinical importance. To determine the sensitivity of transvaginal sonography in the detection of this finding, measured amounts of isotonic saline were instilled into the abdominal cavities of 15 women undergoing diagnostic laparoscopy while a 5-MHz transvaginal probe was employed to view the pelvic contents. Small amounts of free fluid could be visualized easily in all the patients (mean +/- SD, 25.8 +/- 6.4 mL). Fluid was first seen in the cul-de-sac in 10 patients and in the adnexal region in 5. When fluid instillation was continued to a total volume of 200 mL, the pelvic viscera were distinctly outlined in all the patients, markedly enhancing visualization of the uterus, tubes and ovaries. Transvaginal sonography seems to be a sensitive and reliable method of detecting free peritoneal fluid. Instillation of fluid into the peritoneal cavity may be a clinically useful technique for enhancing the sonographic visualization of pelvic structures.