Differential Diagnosis of Polypoid Lesions of the Gallbladder Using Contrast-Enhanced Sonography

Objectives-The purpose of this study was to evaluate the usefulness of real-time contrast-enhanced sonography and microvascular imaging for differential diagnosis of neoplastic and non-neoplastic polypoid lesions of the gallbladder. Methods-Real-time contrast-enhanced sonography and microvascular imaging were performed in 128 patients with polypoid lesions of the gallbladder larger than 6 mm in diameter. The enhancement patterns, microvascular imaging types, and kinetic parameters were analyzed on contrast-enhanced sonography. The maximum diameters of the lesions measured by conventional and contrast-enhanced sonography were also recorded and subjected to a comparative analysis. Results-Among the 128 patients, histologic diagnoses were obtained in 83 (27 neoplastic lesions and 56 non-neoplastic lesions), which constituted the study group. On contrast-enhanced sonography, mild enhancement and absence of contrast were more easily found in non-neoplastic lesions (12 [21.4%]), whereas all neoplastic lesions showed marked enhancement (27 [100%]; P = .006). Of the 27 neoplastic lesions, 6 malignant tumors showed a perfusion defect on contrast-enhanced sonography, whereas none of the non-neoplastic lesions showed a perfusion defect (P = .003). The microvascular architecture of the lesions was categorized into 4 types: spotty, linear, branched, and spinous, and there were significant differences between the groups (P < .001). In a kinetic evaluation, none of the parameters reached statistical significance (all P > .05). There was a discrepancy in maximum diameters between conventional and contrast-enhanced sonography in both groups but the discrepancy was significantly greater in the nonneoplastic group (P = .026). Conclusions-Contrast-enhanced sonography is a useful imaging technique and an adjunct to conventional sonography for differential diagnosis of neoplastic and nonneoplastic polypoid lesions of the gallbladder.