Ultrasonic Distinction of Abscesses from Other Intra-abdominal Fluid Collections

Abstract

The nature of 103 intra-abdominal fluid collections from humans examined by ultrasound was determined by autopsy, needle aspiration, spontaneous drainage or surgical exploration. Abscesses, chronic hematomas, lymphoceles, urinomas, cysts and fluid-filled bowel loops were approximately elliptical or circular in cross section. Collections of ascites had a very irregular outline. Bowel loops appeared as multiple circles, all of similar size. Chronic hematomas contained strongly echoing material, while lymphoceles, urinomas, renal and hepatic cysts and collections of ascites were echo-free. Ovarian cysts into which there was bleeding may contain echoes. The walls of abscesses, chronic hematomas and bowel loops were less sharp than the walls of other collections. Intrahepatic abscesses may have more ragged walls than abscesses elsewhere. Ultrasonic characteristics of abscesses and hematomas overlapped. It was sometimes possible to distinguish the nature of the fluid by its ultrasonic properties, but atypical appearances were not rare.