Contrast-enhanced Ultrasonography for Differential Diagnosis of Protruding Lesions of the Gallbladder

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Objective: We studied the usefulness of contrast-enhanced ultrasonography in assessment of protruding lesions of the gallbladder detected in ultrasonographic mass screening.

Patients and Methods: Twenty-eight patients were suspected to have gallbladder carcinoma based on screening examinations using non-contrast abdominal ultrasonography that detected protruding gallbladder lesions (pedunculated and at least 10 mm in diameter, 25; sessile, 3). We performed contrast-enhanced ultrasonography as a further examination in such patients, and diagnosed malignancy when the findings included high echogenicity, irregularly distributed flow of contrast medium, and a dendriform pattern, while low echogenicity and presence of microcystic structures suggested a benign lesion. We made the final diagnosis based on histopathologic examination of resected specimens or ultrasonographic findings after follow-up for at least 12 months. We determined the diagnostic performance of contrast ultrasonography and extent of surgical resection avoidance achieved with this method.

Results: Sensitivity of contrast ultrasonography in identifying neoplasms was 100% (4/4), specificity was 70.8% (17/24), and overall accuracy was 75.0% (21/28). Surgical intervention was avoided in 64.3% of patients (18/28).

Conclusion: Contrast ultrasonography represents a useful, minimally invasive method for evaluating protruding gallbladder lesions suspected to be cancer in abdominal ultrasonography.