Imaging description

By ultrasound, gallbladder wall edema is present when the gallbladder mural thickness is 3 mm or more (Figure 55.1). The wall may also appear striated, with alternating hypoechoic and hyperechoic layers (Figure 55.2). These imaging features are non-specific in isolation. Additional sonographic signs of acute cholecystitis include the presence of mobile stones or sludge, a non-mobile stone in the gallbladder neck, gallbladder luminal distension, pericholecystic fluid, and extrahepatic and intrahepatic biliary dilation. A sonographic Murphy’s sign (SMS) is positive when there is maximal tenderness over the sonographically localized gallbladder, and negative if the pain is diffuse or localized to a site distant from the gallbladder [1]. If both gallstones and a positive SMS are present with gallbladder wall thickening, the positive predictive value is greater than 90%. Gallbladder wall thickening found in the absence of stones or a SMS has a reported negative predictive value for acute cholecystitis of approximately 95% [1].

Importance

Gallbladder wall edema can be found in patients with both biliary and non-biliary causes of right upper quadrant pain. Additional sonographic features that favor a non-biliary source of the gallbladder wall thickening include sonographic signs of cirrhosis, a hypoechoic liver, and decompressed gallbladder lumen.