EUS elastographic pattern of normal pancreas, pancreatic neoplasm and focal pancreatitis: a preliminary study

Objective: To investigate the elastographic pattern of normal pancreas, pancreatic neoplasm and focal pancreatitis. Methods: Between January 2009 and June 2010, 6 patients (3 males and 3 females, mean age of 46.8 years) with normal pancreas and 19 patients (11 males and 8 females, mean age of 63.6 years) with focal pancreatic lesions were enrolled. The relative stiffness of tissue was described by colors superimposed on the B-mode image: hard tissue areas were marked with blue, intermediate areas with green, medium soft areas with yellow and soft areas with red. Elastographic pattern was scored with whole numbers from 1 to 5 based on the color of elastographic images: score 1 was assigned when the image showed a homogenous green area; score 2 when the image showed a mixture with green, yellow, and red; score 3 was Honeycomb like pattern with blue dominated mixed color; score 4 was assigned when the image showed a homogenous blue area and score 5 was mainly blue area mixed with areas of heterogeneous green and red. The final diagnoses were based on cytohistopathology results of EUS-FNA/surgery, or clinical follow-up of at least 6 months to exclude malignancy in the patients who did not have surgery. Results: Elastography was successfully performed in all patients and there were no procedure-related complications. Among 6 normal patients, elastographic pattern was scored as 1 in 5 patients and 2 in 1. 12 patients with focal pancreatic lesions were finally diagnosed as pancreatic carcinoma, 2 as pancreatic neuroendocrine tumor and 5 as focal pancreatitis. Elastographic pattern of pancreatic carcinoma was scored as 3 in 8 cases, 4 in 1 and 5 in 3. 2 neuroendocrine tumors were scored as 3 and 5 respectively. 5 cases of focal pancreatitis were scored as 2 in 3 cases and 3 in 2. The results indicated that normal and inflammatory tissues are relatively soft and mainly scored 1 and 2, while neoplastic lesion tends to be hard and mainly scored 3–5. When we classified score 1and 2 as benign and score 3 to 5 as malignancy, the overall diagnostic accuracy of EUS elastography for focal pancreatic lesions was 89.47% (17/19). Conclusions: There were apparent differences in elastographic pattern between benign and malignant pancreatic tissues. EUS elastography may provide a complementary method for the differentiation of benign and malignant pancreatic lesion, especially when EUS-FNA is negative or cannot be performed because of technical problems.