抄録
We assessed the diagnostic capability of diffusion-weighted magnetic resonance imaging (DWI) to predict the histological diagnosis of ampullary lesions to resolve the diagnostic uncertainty of endoscopic biopsy for ampullary neoplasms. From January 2009 to August 2011, we performed DWI using b values of 0 and 1000s/mm2 for 15 patients with a histological diagnosis of ampullary lesion (adenocarcinoma, n = 8; adenoma, n = 4; hyperplasia, n = 3). We compared the signal intensities (determined by comparing signal intensities of ampullary lesions and rating them as markedly hyperintense, hyperintense, or hypo-to-isointense relative to the duodenal wall) and the apparent diffusion coefficient (ADC, × 10-3 mm2/s) values of the ampullary lesions on DWI among the three groups based on the histological diagnosis. Values are expressed as median (range). The cancer-group lesions showed a significantly higher signal intensity than either adenoma or hyperplasia (markedly hyperintense/hyperintense/hypo-to-isointense; adenocarcinoma, 7/1/0; adenoma, 0/4/0; hyperplasia, 0/0/3; P < 0.005). The ADC values were significantly lower in adenocarcinoma at 1.46 (0.83-1.63) than in either adenoma at 2.14 (1.92-2.37) or hyperplasia at 2.06 (1.88-2.53) (P < 0.005). In addition, the ADC values in the malignant group (adenocarcinoma) were significantly lower than those in the benign groups (adenoma and hyperplasia) (P < 0.001). The findings suggested that DWI could contribute significantly to accurate preprocedural diagnosis of ampullary lesions.
