Description
Sonographic features of uncomplicated AC include: presence of gallstones (fig.1) or
sludge (fig.2), thickened gallbladder wall more than 4mm (fig.3), enlarged gallbladder
more than 8cm in long axis or more than 4cm in short axis (fig.4), pericholecystis
fluid collection (fig.5), enlargment of biliary tree (fig.6), hyperemic wall upon evaluation
with Color Doppler (fig.7) and positive sonographic Murphy sign. Specially some US
findings are more strongly associated with AC: a positive sonographic Murphy sign with a
sensitivity of 92% and thickened gallbladder wall in the presence of stones with a positive
predictive value of 95%.
Although US is the most useful imaging modality for initial evaluation of AC, MDCT
is helpful when US findings are equivocal or clinical symptoms are nonspecific. The
most sensitive CT findings in uncomplicated AC are inflammation and significant
thickening of the gallbladder wall with mucosal hyperenhancement in the setting of a
distended gallbladder (fig.8-9). Transient focal areas of increased enhancement in the
hepatic parenchyma can be seen adjacent to the inflamed gallbladder, findings probably
caused by reactive hepatic arterial hyperemia. Other findings include haziness of the
pericholecystic fat, pericholecystic fluid, gallstones and increased attenuation of the bile
(fig.8-9). In patients with acute abdominal pain, a combination of some or all of these CT
findings is highly specific for AC, showing a good diagnostic accuracy with a sensitivity
of 92% and a specificity of 99% comparable to those of US.