Prolapsed hyperplastic gastric polyp causing pancreatitis: case report.

A huge hyperplastic gastric polyp prolapsed into the duodenum. The compression and obstruction of the ampulla of Vater by this polyp caused acute pancreatitis. An overview of imaging findings, general considerations about hyperplastic gastric polyps, and a review of the literature are provided.

Intussusception in children: current concepts in diagnosis and enema reduction.

Intussusception cannot be reliably ruled out with clinical examination and plain radiography. However, a contrast material enema study and ultrasonography (US) allow definitive diagnosis of intussusception. The components of an intussusception produce characteristic appearances on US scans. These appearances include the multiple concentric ring sign and crescent-in-doughnut sign on axial scans and the sandwich sign and hayfork sign on longitudinal scans. Indicators of ischemia and irreducibility are trapped fluid at US and absence of blood flow at Doppler imaging. The aim of enema therapy is to reduce the greatest number of intussusceptions without producing perforation. Barium, water-soluble contrast media, water, electrolyte solutions, or air may be used with radiographic or US guidance. The differences in reduction and perforation rates between the various types of enemas are probably due more to perforations that occurred before enema therapy and the pressure exerted within the colon than to the contrast material used. The pressure within the colon is more constant with hydrostatic reduction than with air reduction; this fact may explain the lower risk of perforation with hydrostatic reduction. Radiation exposure is lower with air enema therapy than with barium enema therapy and is absent in US-guided enema therapy.

Intussusception: US findings with pathologic correlation--the crescent-in-doughnut sign.

PURPOSE: To determine the characteristic ultrasound (US) findings of intussusception and to explain its different components. MATERIALS AND METHODS: Three intussusceptions were surgically induced in pigs, and in vitro US scans were compared with the corresponding pathologic slices. US findings in 44 cases of pediatric intussusception confirmed by means of saline enema examination were analyzed. RESULTS: Axial images of intussusception showed a doughnut pattern. The hypoechoic external ring was formed by the everted returning limb of intussusceptum and, to a lesser degree, by the intussuscipiens. The doughnut's center varied according to the scan level. Scans obtained at the middle or at the base of the intussusception showed a characteristic hyperechoic crescent in all cases. This crescent was formed by the mesentery enclosing the entering limb of the intussusceptum, which the authors have termed the "crescent-in-doughnut sign". On scans obtained at the apex of the intussusception, the center was hypoechoic owing to the entering limb of the intussusceptum and the absence of the mesentery. CONCLUSION: The crescent-in-doughnut sign appears to be a characteristic feature of intussusception.