Contribution of ultrasonography and cholescintigraphy to the diagnosis of acute acalculous cholecystitis in intensive care unit patients.

OBJECTIVES: To assess the respective value of ultrasonography (US) and morphine cholescintigraphy (MC) in the diagnosis of acute acalculous cholecystitis (AAC). DESIGN AND SETTING: Prospective study in an intensive care unit of a university hospital. PATIENTS AND INTERVENTION: Twenty-eight patients with clinically and biologically suspected of AAC. US was performed at the bedside and less than 12 h later MC. US was considered positive if three major criteria were present: wall thickness greater than 4 mm, hydrops, sludge; MC results were regarded as positive if the gallbladder could not be visualized. These latter patients underwent cholecystectomy and the diagnosis of AAC was confirmed through histopathological study. MEASUREMENTS AND MAIN RESULTS: Sensitivity of US and MC, respectively, was 50% and 67%, specificity 94% and 100%, positive predictive value 86% and 100%, negative predictive value 71% and 80%, and accuracy 75% and 86%. The correlation between US and MC findings was 71%, with chi = 0.31. By Bayesian analysis the probability of disease if the MC finding was positive was 100% regardless of US results. A positive US finding was associated with a 86% probability of disease, but with a probability of only 66% in case of negative MC results. MC is thus superior to US for confirming AAC in selected critically ill patients. Nevertheless, US is an easy, noninvasive, and effective method of bedside screening. The combination of the two imaging tests improves diagnostic accuracy and reduces false-positive and false-negative rates. Poor agreement between the two tests leads to better diagnostic complementarity.

Contribution of cholescintigraphy to the early diagnosis of acute acalculous cholecystitis in intensive-care-unit patients.

Thirty-two intensive care unit patients (78% on long-term total parenteral nutrition) suspected of having acute acalculous cholecystitis (AAC) were studied prospectively. All of these patients underwent abdominal ultrasonography and cholescintigraphy with technetium-99m mebrofenin. Morphine sulphate (0.04 mg/kg) was administered only if the gallbladder was not visualised after 1 h (16 patients). The final diagnosis was reached after clinical improvement, or upon the discovery of another aetiology for the symptoms presented, or on the basis of histopathology following cholecystectomy (when this was performed). We analysed the contribution of individual cholescintigraphic findings (I: non-visualisation of the gallbladder during the first 60 min of the examination; II: persistent non-visualisation of the gallbladder 30 min following morphine administration; III: non-visualisation of the small bowel for at least 90 min) and their various combinations. We obtained a sensitivity of 79% and a specificity rate 100% using the interpretative criteria "I and II or III". Excluding obstructive syndrome ("I and II"), the sensitivity and specificity figures were 70% and 100% respectively (28 patients). We had no false-positive results in our patient population. Cholescintigraphy was found to complement ultrasonography, which had either good sensitivity (93%) and poor specificity (17%), when at least two of the three major signs were present (sludge, thickened wall, gallbladder distension), or poor sensitivity (36%) and good specificity (89%) when all three signs were present. We conclude that cholescintigraphy is a useful tool for early diagnosis of AAC in critically ill patients, in whom ultrasonography alone does not provide enough information to permit a sufficiently early decision regarding the use of surgery.