Differentiation grade for extrahepatic bile duct adenocarcinoma: Assessed by diffusion-weighted imaging at 3.0-T MR

Purpose : To assess the pathological differentiation grade in the patients with extrahepatic bile duct adenocarcinoma (EBDA) using diffusion-weighted imaging (DWI) at 3.0-T MR. Methods : Sixty-eight patients who were clinically and histologically diagnosed with EBDA underwent abdominal DWI within 2 weeks before surgery. The lesion signal intensity, signal intensity ratio of the lesion and hepar (SIR-LH) value, and apparent diffusion coefficient (ADC) value in patients with EBDA were retrospectively analysed. Results: In the 68 patients, 22 well-differentiated, 36 moderately-differentiated, and 10 poorly differentiated EBDAs were histopathological confirmed. These EBDAs exhibited hyper-intensity on DWI in 95.59% of patients. Hyper-intensity lesions were found in 90.91% of patients with good differentiation, in 97.22% with moderate-differentiation and in 100% with poor-differentiation. There showed no statistical difference for the lesion signal intensity (P = 0.426) and SIR-LH value (P = 0.766) on DWI among three groups. The median ADC value of the well-differentiated, moderately-differentiated and poorly-differentiated EBDAs were 1.506 x 10(-3) mm(2)/s, 1.275 x 10(-3) mm(2)/s and 1.154 x 10(-3) mm(2)/s, respectively. As the pathological differentiation grade decreased, the lesion ADC value of EBDA gradually declined (x(2) = 51.220, P= 0.000). The ADC value <1.184 x 10(-3) mm(2)/s can predict the poorly-differentiated EBDA with a sensitivity of 100% and a specificity of 94.83%. The ADC value >1.316 x 10(-3) mm(2)/s can forecast the well-differentiated EBDA with a sensitivity of 100% and a specificity of 84.78%. Conclusions : The histopathological differentiation grade of EBDA can be detected non-invasively using DWI at 3.0-T MR. (C) 2016 Elsevier Ireland Ltd. All rights reserved.