Figure 5b. Emphysematous cholecystitis. (a) Contrast material-enhanced CT scan through the upper abdomen demonstrates gas within the gallbladder wall (black arrows) and lumen (*) and cholelithiasis (white arrow). (b) CT scan obtained cephalad to a shows an area of air attenuation centrally within the liver (white arrow) secondary to associated pneumobilia. A feeding tube is seen within the duodenum (black arrow). (c) Photograph of the gross specimen reveals evidence of perforation within a large area of transmural necrosis (arrows).