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

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.

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.

-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 1.506×10^-3mm²/s, 1.275×10^-3mm²/s and 1.154×10^-3mm²/s, respectively. As the pathological differentiation grade decreased, the lesion ADC value of EBDA gradually declined (x²=51.220, P=0.000). The ADC value <1.184×10^-3mm²/s can predict the poorly-differentiated EBDA with a sensitivity of 100% and a specificity of 94.83%. The ADC value >1.316×10^-3mm²/s can forecast the well-differentiated EBDA with a sensitivity of 100% and a specificity of 84.78%.

The histopathological differentiation grade of EBDA can be detected non-invasively using DWI at 3.0-T MR.