Clinical and Radiologic Diagnosis of Emphysematous Cholecystitis
Emphysematous cholecystitis is a form of cholecystitis caused by gas-forming organisms, most
commonlyE. coli and Klebsiella. Gallstones are often present, although there are cases
associated with AC. Those most prone to infection are diabetics and the elderly. Mortality rates
are much higher than with nonemphysematous cholecystitis (21,25).
Gas within the gallbladder wall may be identified on radiographs. The most sensitive
and specific test is CT, which not only demonstrates gas in the gallbladder wall, but also may
show spread of inflammation and, in some cases, gas into surrounding tissues and into the rest
of the biliary system (21,25).
Mimic of Emphysematous Cholecystitis
Aside from calculous and AC, gas in the biliary system from a biliary-enteric fistula
(spontaneous or iatrogenic) is a differential consideration in the diagnosis of emphysematous
cholecystitis, although relatively rare (Fig. 10). Specific considerations include gallstone
ileus (i.e., chronic cholecystitis with fistula to the adjacent small bowel) and malignancy.
Extension of inflammation into the pericholecystic tissues and extrahepatic ducts may be a
helpful differentiating feature, as this is considered more specific for emphysematous
cholecystitis (25).
Clinical and Radiologic Diagnosis of Pancolitis
Colonic infection results from bacterial, viral, fungal, or parasitic infections. An increasingly
prevalent agent in both hospitalized and nonhospitalized patients isClostridium difficile.
Plain film findings ofC. difficilecolitis include polypoid mucosal thickening, haustral fold
thickening or “thumbprinting” represented by widened opaque transverse bands, and gaseous
distention of the colon. On CT, the colonic wall is thickened and low in attenuation, secondary
to edema (Fig. 11). Wall thickening may be circumferential, eccentric, smooth, irregular, or
polypoid, and ranges from 3 mm to 32 mm. There is mucosal and serosal enhancement.
Inflammation of the pericolonic fat and ascites may be present. The “target sign” consists of
two to three concentric rings of different attenuation within the colonic wall and represents
mucosal hyperemia and submucosal edema or inflammation. This sign is helpful, but not very
specific, as it is also seen in inflammatory bowel disease, including ulcerative colitis (UC),
amongst other disorders. The “accordion sign” is due to trapping of oral contrast between
markedly thickened haustral folds, resulting in alternating bands of high and low attenuation,
oral contrast, and edematous bowel wall, respectively. Pericolonic fat stranding, while often
present, is generally mild in comparison with the degree of bowel wall thickening, which may
be helpful in differentiatingC. difficilefrom inflammatory colitis (3,26).
Figure 10 CT scan of the abdomen demon-
strates air in the gallbladder [which also contains
gallstones (arrow)], secondary to erosion of the
stomach into the biliary system in a 71-year-old
male with metastatic gastric cancer. A gastro-
stomy tube is also present.84 Luongo et al.