Intravenous computed tomographic cholangiography in acute cholecystitis. A comparison with conventional cholangiography

Part 1: Current Concepts in Radiologic Imaging and Intervention in Acute Cholecystitis

Acute calculous cholecystitis and acute acalculous cholecystitis are encountered commonly among critically ill, often elderly, patients. Multidisciplinary management of these conditions is essential, with intensivists, surgeons, diagnostic radiologists, interventional radiologists, infectious disease physicians, gastroenterologists, and endoscopists able to contribute to patient care. In this article intended predominantly for intensivists, we will review the imaging findings and radiologic treatment of critically ill patients with acute calculous cholecystitis and acute acalculous cholecystitis.

Contrast Enhancement of Liver Parenchyma and Biliary Tract Related to Liver Function at Delayed Computed Tomography

Computed tomography (CT) of the liver was performed in 53 patients before, during and 4 to 6 hours after intravenous administration of approximately 60 g of iodine in metrizoate. At delayed CT, contrast medium was observed in the extrabiliary ducts in 20 patients (38%) and in the gallbladder in 28 (68%) of the 41 patients with no previous cholecystectomy. The increase in attenuation of liver parenchyma at delayed CT compared with the non-enhanced baseline CT ranged between 2 and 26 HU (mean 13.9). The material was divided into three groups with regard to liver function: normal, intermediate and pathologic. In the normal group contrast medium was observed in the gallbladder in 81 per cent and in the bile ducts in 57 per cent and the mean increase in attenuation of the liver parenchyma was 14.5 HU. In the pathologic group the same parameters were 40 per cent, 7 per cent and 10.6 HU, respectively. Contrast medium in the gallbladder and biliary ducts improved the information about anatomy. Pathology of the gallbladder and tumour growth along the hepatoduodenal ligament were better demonstrated. Delayed CT is a simple and non-invasive technique that may improve planning of liver surgery.

A systematic review and meta-analysis of diagnostic performance of imaging in acute cholecystitis

PURPOSE

To update previously summarized estimates of diagnostic accuracy for acute cholecystitis and to obtain summary estimates for more recently introduced modalities.

MATERIALS AND METHODS

A systematic search was performed in MEDLINE, EMBASE, Cochrane Library, and CINAHL databases up to March 2011 to identify studies about evaluation of imaging modalities in patients who were suspected of having acute cholecystitis. Inclusion criteria were explicit criteria for a positive test result, surgery and/or follow-up as the reference standard, and sufficient data to construct a 2 × 2 table. Studies about evaluation of predominantly acalculous cholecystitis in intensive care unit patients were excluded. Bivariate random-effects modeling was used to obtain summary estimates of sensitivity and specificity.

RESULTS

Fifty-seven studies were included, with evaluation of 5859 patients. Sensitivity of cholescintigraphy (96%; 95% confidence interval [CI]: 94%, 97%) was significantly higher than sensitivity of ultrasonography (US) (81%; 95% CI: 75%, 87%) and magnetic resonance (MR) imaging (85%; 95% CI: 66%, 95%). There were no significant differences in specificity among cholescintigraphy (90%; 95% CI: 86%, 93%), US (83%; 95% CI: 74%, 89%) and MR imaging (81%; 95% CI: 69%, 90%). Only one study about evaluation of computed tomography (CT) met the inclusion criteria; the reported sensitivity was 94% (95% CI: 73%, 99%) at a specificity of 59% (95% CI: 42%, 74%).

CONCLUSION

Cholescintigraphy has the highest diagnostic accuracy of all imaging modalities in detection of acute cholecystitis. The diagnostic accuracy of US has a substantial margin of error, comparable to that of MR imaging, while CT is still underevaluated.