Figure 5a. Gallbladder perforation associated with acute gangrenous cholecystitis in a 78-year-old woman with right upper quadrant pain and a high fever. MR imaging was performed because of US findings suggestive of a pericholecystic abscess. (a) Image from single-section MR cholangiopancreatography shows a distended gallbladder (arrowhead) with an irregular contour of the fundus and stenosis of the common hepatic duct (arrow) due to extrinsic compression by the gallbladder. (b, c) Axial heavily T2-weighted (b) and fat-suppressed T2-weighted (c) images show gallbladder wall thickening (arrowhead) and purulent bile (*), which like a sludge forms a lower layer of low signal intensity. A pericholecystic abscess (open arrow) is seen as an area of slightly higher signal intensity. The gallbladder wall is disrupted (solid arrow), and purulent bile is present outside the gallbladder; this bile is contained by the pericholecystic abscess. (d) Axial fat-suppressed T1-weighted image shows the purulent bile (*) as a lower layer of intermediate signal intensity. The purulent bile communicates with the pericholecystic abscess (open arrow) through the site of perforation (solid arrow).