The walled-off necrosis fully developed with a complete enhancing wall and internal foci with the fat density. The air bubbles within the walled-off necrosis in the first series could be due to recent ERCP, but infected necrosis should be excluded. The gallstones visible on previous CT scans are no longer visible. The gallbladder contains air, and a fistulous tract from the gallbladder fundus to the hepatic flexure of the colon is visible, suggestive of fistulization. The stones are now visible within the lumen of the colonic hepatic flexure(first series).