[Preliminary study of pelvic CT with air enema].

In pelvic CT, several techniques (appropriate preparations) have been reported for the optimal diagnostic imagings. We demonstrated the usefulness and limitations of "Air Enema", which is one of preparations for hollow viscera in pelvic CT examination. From Oct. 1986 to Mar. 1987, 38 patients with gynecological abnormalities were evaluated by consecutive pre and post "Air Enema" CT. The patients aged 26-75 years with mean of 44.6 years. All patients were examined in prone position with 100 ml of 2% iopamidol in the urinary bladder and medical tampon in the vagina. Two consecutive scans were performed from the level of pubic symphysis to the 5th lumbar vertebra at 10 mm-15 mm intervals. The first scan was pre "Air Enema" CT, in which the rectum, entire colon and terminal ileum were not distended. The second scan was post "Air Enema" CT, in which the hollow viscera was distended by 1000 ml-1500 ml of air. Two images, each from pre and post "Air Enema" CT were evaluated on the efficacy for imaging diagnosis. In "Air Enema" CT, main useful effect was "replacement effect", which was that intrapelvic masses and/or intrapelvic paravascular spaces were clearly delineated by distended bowels. Detection and location of intrapelvic masses were correctly diagnosed when the masses were relatively small (5.3 cm in average diameter), but there were no advantages in cases in which the pelvic masses were large enough to occupy the pelvic cavity (12.7 cm in average diameter). Abdominal pain was the most common adverse reaction to this technique. But complaints usually disappeared in few hours after examination. Thus, "Air Enema" seems to be useful preparation for pelvic CT examination to detect relatively small intrapelvic masses and abnormalities.