A comparison of the diagnostic accuracy of ultrasound, computer tomography and ERPC in chronic or recurrent pancreatitis and pancreatic carcinoma has shown that ERPC is the most precise of the three methods. This was particularly important in the demonstration of the small, still operable, carcinomas of the pancreas. Sonography is most useful for serial observations of pancreatic pseudocysts due to chronic recurrent pancreatitis. In this situation, ERPC should only be used if sonography and computer tomography cannot localise the lesion. Where the computer tomogram has shown evidence of enlargement of the pancreas, sonography may show an area devoid of echos within the enlarged organ, suggesting the presence of a carcinoma. Computer tomography superior to ultrasonography in delineating the extent of extensive pancreatic disease and in showing the anatomical structures surrounding the pancreas.