The value of MDCT scans in differentiation between benign and malignant gallbladder wall thickening

To evaluate the value of MDCT in differentiation of gallbladder carcinoma from other benign conditions in patients with thickened gallbladder wall.

MDCT of 125 patients, 18 gallbladder carcinomas and 107 other benign conditions were retrospectively reviewed. Various direct and indirect CT findings of benign and malignant gallbladder diseases were evaluated. Differences in CT findings between benign and malignancy were calculated using Chi-square test and odds ratio. Additionally, the wall enhancement pattern was evaluated and categorized into five types, according to the presence of striation, thickness of the outer and inner layers, and degree of enhancement of each layer compared with that of normal liver parenchyma. The diagnostic performance of enhancement pattern analysis on MDCT was analyzed.

Five direct and five indirect CT findings including wall irregularity focal wall thickening, discontinuous mucosa, submucosal edema, polypoid mass, direct invasion to adjacent organ, biliary obstruction, regional and paraaortic lymphadenopathy and distant metastasis show significant differences between benign and malignancy. The thickened gallbladder wall with one-layer heterogeneous enhancement (type 1) was significantly associated with malignancy. By using type 1 enhancement pattern as the predictor for malignancy, the sensitivity, specificity, and accuracy of MDCT for detection of malignancy was 78%, 94% and 92%, respectively.

MDCT is a reliable diagnostic method for differentiating between benign and malignant thickened gallbladder wall. Focal and irregular wall thickening are two direct signs that most associated with malignancy. Moreover, the one-layer heterogeneous enhancement of gallbladder wall is suggestive of malignancy.