Differentiation of Pancreatic Tumours by Conventional Ultrasound, Unenhanced and Echo-Enhanced Power Doppler Sonography

Abstract

Background: Echo-enhanced power Doppler sonography (power Doppler sonography after injection of a contrast agent) is a non-invasive and increasingly used procedure for differentiating between pancreatic tumours. However, the diagnostic accuracy of this method compared to conventional ultrasound or unenhanced power Doppler sonography has never been investigated in a large prospective controlled study. Methods: 137 patients were included in the study, selected from 190 consecutive patients with a mean age of 60 years (range 16-85) who presented at our department in the period January 1998 through June 2001 with clinical suspicion of a pancreatic tumour. Sonography was performed by an experienced examiner blind to the patients' clinical diagnoses. The exact diagnosis was based on histological evidence from biopsy examination (surgical and fine needle biopsy) or on a follow-up of at least 18 months. Results: Of the 137 patients, 47 had pancreatic cancer; 41 had masses associated with pancreatitis; 17 had neuroendocrine tumours; 12 had cystic lesions of the pancreas; and 10 had other pancreatic diseases. A normal pancreas was found in 10 patients. The sensitivity of echo-enhanced power Doppler sonography with respect to diagnosing pancreatic carcinoma was 87% and its specificity 94%. The corresponding values for chronic pancreatitis were 85% and 99%, respectively. Conclusions: Echo-enhanced power Doppler sonography has a high sensitivity and specificity in the differential diagnosis of pancreatic tumours. However, histology is the standard of reference.