Echogenic clot: a useful sign of pelvic hemoperitoneum

The sonograms of 34 patients with surgically proved pelvic hemoperitoneum were reviewed. In 15 of these patients clotted blood was found at surgery in the pelvis or cul-de-sac. In nine of these patients (60%), ultrasound demonstrated echogenic fluid collections or "masses" with an echogenicity equal to or greater than the uterus. Because anechoic fluid in the pelvis is a nonspecific finding, awareness that clotted blood can be highly echogenic may be of considerable value in the differential diagnosis of pelvic fluid collections. The limitations and pitfalls in interpreting this finding are discussed.