ULtrasonography in acute cholecystitis

Computed tomography versus ultrasound for the diagnosis of acute cholecystitis: a systematic review and meta-analysis

OBJECTIVES

Some patients undergo both computed tomography (CT) and ultrasound (US) sequentially as part of the same evaluation for acute cholecystitis (AC). Our goal was to perform a systematic review and meta-analysis comparing the diagnostic performance of US and CT in the diagnosis of AC.

MATERIALS AND METHODS

Databases were searched for relevant published studies through November 2023. The primary objective was to compare the head-to-head performance of US and CT using surgical intervention or clinical follow-up as the reference standard. For the secondary analysis, all individual US and CT studies were analyzed. The pooled sensitivities, specificities, and areas under the curve (AUCs) were determined along with 95% confidence intervals (CIs). The prevalence of imaging findings was also evaluated.

RESULTS

Sixty-four studies met the inclusion criteria. In the primary analysis of head-to-head studies (n = 5), CT had a pooled sensitivity of 83.9% (95% CI, 78.4-88.2%) versus 79.0% (95% CI, 68.8-86.6%) of US (p = 0.44). The pooled specificity of CT was 94% (95% CI, 82.0-98.0%) versus 93.6% (95% CI, 79.4-98.2%) of US (p = 0.85). The concordance of positive or negative test between both modalities was 82.3% (95% CI, 72.1-89.4%). US and CT led to a positive change in management in only 4 to 8% of cases, respectively, when ordered sequentially after the other test.

CONCLUSION

The diagnostic performance of CT is comparable to US for the diagnosis of acute cholecystitis, with a high rate of concordance between the two modalities.

CLINICAL RELEVANCE STATEMENT

A subsequent US after a positive or negative CT for suspected acute cholecystitis may be unnecessary in most cases.

KEY POINTS

When there is clinical suspicion of acute cholecystitis, patients will often undergo both CT and US. CT has similar sensitivity and specificity compared to US for the diagnosis of acute cholecystitis. The concordance rate between CT and US for the diagnosis of acute cholecystitis is 82.3%.

Cholecystosonographic evaluation of the prevalence of gallbladder diseases. A university hospital experience

Ninety-five healthy volunteers and 515 patients with problems other than those of the biliary tract were examined using real-time, gray-scale, B-mode ultrasonography. Eighty-two patients (13.44%) were found to have asymptomatic gallbladder disease: 68 (11.14%) had cholelithiasis, 5 (0.81%) had acalculus cholecystitis, and 2 (0.32%) had polyps. Three cases of carcinoma of the gallbladder were also detected, suggesting that ultrasound examination of the high-risk population in an endemic area should not be confined to the disease concerned but that the gallbladder of such patients should also be screened to pick up asymptomatic gallbladder disease. Hence ultrasound can be used as a screening modality for the early detection of carcinoma of the gallbladder.

Diagnostic accuracy of ultrasound in acute cholecystitis

This work attempts to assess the diagnostic accuracy of ultrasound for acute cholecystitis in 98 clinically suspected patients from the emergency unit in whom at least 3 of 6 relevant criteria are present. Gallbladder distention to 5 cm or more transversely or in the anterior-posterior axis (criterion 1) was present in 64 patients; thickening of the gallbladder wall of at least 5 mm (criterion 2) in 95; cholelithiasis (criterion 3) in 86; sonolucent halo in the gallbladder wall (criterion 4) in 40; sonolucent fluid band surrounding the gallbladder (criterion 5) in 27; and intraluminal echogenic mass with no posterior acoustic shadow (criterion 6) in 35. A diagnostic accuracy index, corrected for chance, was statistically and clinically more relevant with 3 as the minimum number of criteria for the ultrasonic diagnosis of acute cholecystitis.

Ultrasonography in the diagnosis of acute cholecystitis

Eighty-two patients with right upper quadrant pain and a clinical suggestion of acute cholecystitis had their gallbladder and biliary ducts ultrasonographically examined in the period immediately following admission to the hospital. Biliary calculi or signs of cholecystitis, or both, were found in 65 per cent of the cases at ultrasound examination. An additional 10 per cent had pathologic changes unrelated to the biliary tract. In 44 of 48 cases the presence of calculi or inflammation could be confirmed at surgery, autopsy or endoscopic retrograde cholangiopancreaticography. Only one patient with a normal ultrasound examination was later found to have a small calculus in a common bile duct of normal caliber.