The diagnostic value of grading hyperperfusion and the rim sign in cholescintigraphy

Biliary scans of 84 hospitalized patients believed to likely have acute cholecystitis, including 55 scans that had a radionuclide angiography phase, were retrospectively evaluated to determine the frequency of the rim sign and hyperperfusion, and to test the hypothesis that more intense hyperperfusion or rim sign is associated with a greater severity of gallbladder pathology ("complicated" acute cholecystitis). In 65 of the 84 cases there was surgical intervention (including 43 from the 55 cases whose scans had a radionuclide angiography phase). "Complicated" acute cholecystitis was considered present if there was gangrene, perforation, empyema, necrosis, ulceration, or fibrous exudation. Each scan was evaluated for the presence of a rim sign and arterial hyperperfusion to the region of the gallbladder fossa. The intensities of these secondary signs of acute cholecystitis were then graded as "mild" or "marked." Subdividing the rim sign and hyperperfusion into a "marked" category considerably improved the specificity, positive predictive value, and likelihood ratio (positive) for the diagnosis of acute cholecystitis, but even more so for the complicated subgroup when marked hyperperfusion or marked rim sign were the criteria used for a positive study. Approximately 50% of the patients with acute cholecystitis had hyperperfusion and a rim sign, and approximately 15% had marked hyperperfusion and a marked rim sign. Of the patients with acute cholecystitis, the only ones with marked hyperperfusion or a marked rim sign were those who had complicated acute cholecystitis. The data demonstrate an association between greater intensity of the rim sign or hyperperfusion and greater severity of gallbladder pathology in patients with acute cholecystitis.(ABSTRACT TRUNCATED AT 250 WORDS)