Radiologic findings are described in 4 cases of annular pancreas in adults. The value of double contrast exploration of the duodenum is emphasized, this showing the characteristic image of "curtain-loop" stenosis of the right D2 border with associated marked dilatation of the suprastenotic duodenal zone. Ultrasound imaging shows features suggestive of the liquid distended genu superius. The onset of acute pancreatitis on an annular pancreas leads to images of pseudo-cystic necrosis and/or calcifications suggestive of the diagnosis because of their localization on ultrasound or C.T. examination.