INTUSSUSCEPTION - TRAPPED PERITONEAL-FLUID DETECTED WITH US - RELATIONSHIP TO REDUCIBILITY AND ISCHEMIA

PURPOSE: To determine the frequency and meaning of fluid inside the in tussusception at ultrasound (US) and its relationship to irreducibilit y and ischemia. MATERIALS AND METHODS: US enabled the diagnosis of int ussusception in 145 cases. Shape and axial diameters of the area of fl uid were determined. US-guided hydrostatic reduction was attempted in 144 cases. RESULTS: Fluid was present in the intussusception in 20 cas es (14%) and appeared on axial images as an anechoic crescent between both serosal layers of the enfolded and everted intussusceptum. No cys tic structural anomaly was detected at surgery. Rates of reduction wer e 89% (111 of 125) in cases without fluid and 26% (five of 19) in case s with fluid (P < .001). At surgery, ischemia was absent in all 14 cas es without fluid and present in 10 of 20 cases with fluid; necrosis wa s present in two cases with fluid. Areas of fluid greater than 14 x 5 mm, especially if associated with fluid in the dilated apex of the int ussusception, were strongly related to irreducibility and ischemia (od ds-likelihood ratio, 67.5). CONCLUSION: Fluid seen inside the intussus ception represented trapped peritoneal fluid. Substantial amounts of f luid were associated with irreducibility and ischemia.