Improved differentiation of pancreatic tumours using contrast enhanced endoscopic ultrasound

Aim: Endoscopic ultrasound is a widely accepted imaging method for staging of ductal adenocarcinoma and the localization of neuroendocrine tumours of the pancreas. We prospectively evaluated conventional colour Doppler imaging (CDI) and contrast enhanced endoscopic Doppler ultrasound (CE-EDUS) as a new imaging technique for further characterization and differentiation of solid pancreatic tumours.

Methods: From 300 patients with pancreatic lesions investigated using contrast enhanced endoscopic ultrasound we could finally include 93 patients with undetermined solitary predominantly solid lesion=40mm and definite histological proven diagnosis. After bolus injection of the contrast agent LevovistÒ 4g (400mg/dl) the vascular pattern of the lesion during the arterial phase was compared to the vascularity of the residual pancreatic parenchyma.

Results: In none of the patients CDI revealed vascularity of the pancreatic parenchyma and, therefore, tumour hypovascularity could not be determined in contrast to all CE-EDUS-examined patients revealing at least some degree of parenchymal vascularity. 57 of 62 patients with ductal adenocarcinoma of the pancreas showed a hypovascularity of the tumour using CE-EDUS. All other pancreatic lesions revealed an iso- or hypervascular pattern using contrast enhanced endoscopic ultrasound (20 neuroendocrine tumours, 10 serous microcystic adenoma, one teratoma). Hypovascularity as a sign of malignancy in contrast enhanced endoscopic ultrasound obtained 92% (82–97%) sensitivity and 100% specificity (89–100%).

Conclusions: Contrast-enhanced endoscopic ultrasound is effective in differentiating small solid pancreatic tumours of different origin in most cases. Hypovascularity indicates malignancy of pancreatic tumours.