Diagnostic Ability of Diffusion-weighted Magnetic Resonance Imaging to Discriminate Ampullary Neoplasms: A Preliminary Study of 15 Cases

Abstract

: 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 1000 s / mm 2 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 coef cient ADC, 10 3 mm 2 / 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 signi cantly 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 signi cantly 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 ndings suggested that DWI could contribute signi cantly to accurate preprocedural diagnosis of ampullary lesions.