Chronic pancreatitis: the diagnostic significance of pancreatic size and echo amplitude.

Pancreatic size and pancreatic echo amplitude were examined to determine their value for distinguishing chronic pancreatitis from normal. Using patients with cystic fibrosis as a model for chronic pancreatitis, a prospective study was performed comparing 16 patients with this disease and 16 normals. Absolute measurements of the pancreatic body and the ratio of pancreatic size to vertebral body size were determined. Pancreatic echo amplitude was both measured clinically from the B-scan and evaluated in a blind review by seven observers. The pancreases of cystic fibrosis could be distinguished on the basis of echo amplitude with sensitivity and specificity of 94 per cent and 100 per cent for direct B-scan echo amplitude measurements and 74 per cent and 88 per cent for reviewers. Pancreatic size was of no value as a distinguishing characteristic, probably because as the diseased pancreas increases in echo amplitude by fat and fibrous tissue replacement, it blends imperceptibly with the peripancreatic soft tissues. Measurement of pancreatic size in chronic pancreatitis is therefore inaccurate and probably overestimated.