Discrimination of gangrenous from uncomplicated acute cholecystitis: Accuracy of CT findings

Abstract

In acute cholecystitis, the presence of gangrene is associated with higher morbidity and mortality and necessitates open surgical intervention rather than laparoscopic cholecystectomy. As Murphy's sign may be absent, gangrene may not be detected ultrasonographically. This retrospective study evaluated indications of acute gangrenous cholecystitis on computed tomography (CT) in 25 patients, who were proven as having acute cholecysitis surgically and pathologically within 3 days of pre-operative CT. The CT images were reviewed by two board-certified radiologists blind to the initial CT report. Acute gangrenous cholecystitis was significantly correlated with the CT signs of perfusion defect (PD) of the gallbladder wall (P = 0.02), pericholecystic stranding (PS) (P = 0.028), and no-gallstone condition (No-ST) (P = 0.026). The presence of PD was associated with acute gangrenous cholecystitis with a relatively high accuracy (80%), a sensitivity of 70.6%, a specificity of 100%, a positive predictive value (PPV) of 100%, and a negative predictive value (NPV) of 61.5%. The combination CT signs of PD or No-ST improved the accuracy for acute gangrenous cholecystitis to 92%, with a sensitivity, specificity, PPV, and NPV of 88.2%, 100%, 100%, and 80%, respectively. Other CT signs were highly specific for acute gangrenous cholecystitis but of low sensitivity, including mucosal hemorrhage, mucosal sloughing, wall irregularity, pericholecystic abscess, gas formation, and portal venous thrombosis. CT was found to accurately diagnose acute cholecystitis, with the presence of PD, PS, or No-ST significantly correlated with that of gangrenous change. Thus, CT is useful in the preoperative detection of acute gangrenous cholecystitis.

Contrast-enhanced ultrasonography to diagnose complicated acute cholecystitis

“…Our data support the conclusions of previous studies about CT scan in gangrenous cholecystitis, in which an irregular gallbladder wall enhancement on ceCT scan was reported to be a specific sign of gangrenous changes, although it requires meticulous searching [4,5]. An irregular contrast enhancement of gallbladder walls showing tiny focal defects within the inner mucosal layer was observed in all cases of gangrenous cholecystitis of our series, irrespective of the additional presence of perforation.…”

“…Complications of acute cholecystitis have characteristic CT scan findings, including necrosis, perforation, abscesses, intraluminal hemorrhage, and wall emphysema. Defect in the gallbladder mucosa or sloughed intraluminal membranes suggests gangrene as well as focal transmural defect in the walls [4,5].…”

“…Abdominal contrast-enhanced computed tomography (ceCT) scan is utilized in patients with an acute abdomen when sonography is inconclusive, and it is regarded as the mainstay modality for complicated cholecystitis. Its accuracy in the detection of acute gangrenous cholecystitis has been reported to range from 80 to 92 % for the detection of wall perfusion defects [4,5].…”

Sonography of gangrenous cholecystitis

“…In gangrenous cholecystitis, focal perfusion defects are present within the necrotic wall of the gall bladder;, this is not present in patients with cholecystitis, where perfusion is actually increased from wall inflammation. This important sign was confirmed by Wu et al .,[11] when reviewing Computed tomography (CT) imaging of 25 patients with gangrenous cholecystitis. They found that there was a significant correlation between CT perfusion defects of the gall bladder wall and the presence of gall bladder wall necrosis.…”

Evaluating Patients with Right Upper Quadrant Pain

“…The presence of pericholecystic fluid, degree of gallbladder distention in the short axis, and degree of mural thickening were also predictive of the severity of gallbladder inflammation. In a more recent study by Wu and colleagues, 155 the presence of a perfusional defect of the gallbladder wall (discontinuity or decreased enhancement of the gallbladder wall), was associated with CT diagnosis of gangrenous cholecystitis with accuracy of 80%, sensitivity of 70.6%, specificity of 100%, and positive predictive value of 100%. These studies show that intravenous contrast should be administered if possible because this improves delineation of the wall and identification of lack of enhancement, intramural abscess, or focal disruption, all of which are important features of gangrenous cholecystitis.…”