Abstract: Objective To assess the accuracy of color Doppler imaging in diagnosing the involvement of peripancreatic vessels by pancreatic carcinoma. Methods We prospectively evaluated the color Doppler images of 47 pancreatic carcinomas.Our evaluation focused on vascular involvement.Absence of contact or a short contiguity(≤2cm) between tumors and peripancreatic vessels was considered to be a sign of resectability on color Doppler imaging;a long contiguity(＞2cm),compression,encasement,or thrombosis was considered to be a sign of unresectability.In all patients,the sonographic diagnosis was compared with the surgical results. Results With color imaging,we detected signs of vascular involvement in 20 of 22 patients in whom vascular involvement was found at surgery,we detected no vascular in 20 of 25 patients in whom no vascular involvement was found at surgery.No false-positive diagnosis occurred when vascular encasement was revealed by color Doppler imaging.For diagnosis of vascular involvement,the sensitivity,specifity and overall accuracy of color Doppler imaging were 80%,91%and 85%,respectively;Positive and negative predictive values were 91%and 80%,respectively. Conclusion Color Doppler imaging is a sensitive and highly specific technique in assessing vascular involverment by pancreatic cancer when absence of contact or vascular encasement is seen.When vascular encasement is detected by color Doppler imaging,a definitive diagnosis of unresectability can be made,and further diagnostic procedures can be avoided.