Info

with acute or chronic biliary type pain in the absence of demonstrable calculi (see section on Biliary-Type Pain in the Absence of Calculi). Emptying rates and patterns of emptying have not been sufficiently studied to determine their relevance.

Time activity curves generated from regions over the heart, liver, and bile ducts offer no advantage over biochemical indices in assessing liver function but may be of value in partial obstruction or sphincter of Oddi dysfunction (see section on Postcholecystectomy Pain).

Acute Calculous Cholecystitis: The Emergency Room Setting

The vast majority of outpatients presenting with symptoms of acute cholecystitis have cystic duct obstruction by calculi. Ultrasound is typically the initial imaging

Figure 7. Rim sign in acute cholecystitis. 15 minute (a) and 15 minute post morphine (b) images fail to demonstrate any filling of the gallbladder indicating cystic duct obstruction in this 42 year old man with acute right upper quadrant pain. The inflamed liver adjacent to the gallbladder fossa shows delayed excretion compared with the remainder of the liver (arrowheads). This finding adds specificity to the diagnosis of acute cholecystitis.

Figure 7. Rim sign in acute cholecystitis. 15 minute (a) and 15 minute post morphine (b) images fail to demonstrate any filling of the gallbladder indicating cystic duct obstruction in this 42 year old man with acute right upper quadrant pain. The inflamed liver adjacent to the gallbladder fossa shows delayed excretion compared with the remainder of the liver (arrowheads). This finding adds specificity to the diagnosis of acute cholecystitis.

procedure. It is usually readily available in the emergency room setting, can assess multiple abdominal organs and yields results quickly. It is the procedure of choice to detect calculi in the gallbladder with a sensitivity approaching 98%. In the presence of acute inflammation it can show thickening of the gallbladder wall, pericholecystic fluid, and elicit localized tenderness (the sonographic Murphy's sign). Unfortunately, calculi are a common problem and unless they are located in the gallbladder neck or cystic duct, they imply acute cholecystitis in only 50 to 70% of cases. Gallbladder wall thickening and fluid are infrequent findings and are also nonspecific, being found with ascites and other edematous states. CT has similar advantages and disadvantages. It is better at demonstrating the distal portion of the common bile duct, which may be obscured by gas on US, but clearly cannot be used to assess tenderness over the gallbladder.

In this setting, nonvisualization of the gallbladder within 60 minutes on scintigraphy has a sensitivity for acute cholecystitis approaching 100%. The finding is unreliable if biliary excretion is reduced as a result of hepatocellular disease or cholestasis. Of patients with proven chronic cholecystitis, 80% will show normal gallbladder filling and the remainder will have delayed visualisation (after 1 hour) or persistent nonvisualization. The latter results in an unavoidable number of false positive studies. The proportion depends on the prevalence of chronic cholecystitis in the population studied.

Infusion of morphine at a dose of 0.04 to 0.10 mg/kg is used to accelerate filling of the gallbladder by causing spasm of the sphincter of Oddi and increasing intrabiliary pressure. Morphine-induced gallbladder visualization usually occurs within 30 minutes and imaging beyond that time is unnecessary unless there is delayed excretion.

0 0

Post a comment