Published in:
01-04-2014 | Gastrointestinal
The role of diffusion-weighted MR imaging for differentiating benign from malignant bile duct strictures
Published in: European Radiology | Issue 4/2014
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Objectives
To assess the added value of diffusion-weighted imaging (DWI) to conventional magnetic resonance imaging (MRI) for differentiating benign from malignant bile duct strictures.
Methods
Twenty-seven patients with a benign stricture and 42 patients with a malignant stricture who had undergone gadoxetic acid-enhanced MRI with DWI were enrolled. Qualitative (signal intensity, dynamic enhancement pattern) and quantitative (wall thickness and length) analyses were performed. Two observers independently reviewed a set of conventional MRI and a combined set of conventional MRI and DWI, and receiver operating characteristic (ROC) curve analysis was assessed.
Results
Benign strictures showed isointensity (18.5–70.4 %) and a similar enhancement pattern (22.2 %) to that of normal bile duct more frequently than malignant strictures (0–40.5 % and 0 %) on conventional MRI (P < 0.05). Malignant strictures (90.5–92.9 %) showed hypervascularity on arterial and portal venous phase images more frequently than benign strictures (37.0–70.4 %) (P < 0.01) On DWI, all malignant strictures showed hyperintensity compared with benign cases (70.4 %) (P < 0.001). Malignant strictures were significantly thicker and longer than benign strictures (P < 0.001). The diagnostic performance of both observers improved significantly after additional review of DWI.
Conclusions
Adding DWI to conventional MRI is more helpful for differentiating benign from malignant bile duct strictures than conventional MRI alone.
Key points
• Accurate diagnosis and exclusion of benign strictures of bile duct are important.
• Diffusion-weighted MRI helps to distinguish benign from malignant bile duct strictures.
• DWI plus conventional MRI provides superior diagnostic accuracy to conventional MRI alone.