Morphologic changes in the body of the pancreas secondary to a mass in the pancreatic head. Analysis by CT.

CT scans of 279 normal subjects and 78 patients with a pancreatic head mass were reviewed. The mean width of the pancreatic body in normal subjects was 15.8 +/- 2.9 mm, but the width decreased with age. The pancreatic head to body width ratio (H/B ratio) was constant (1.45 +/- 0.03). In 56 patients with carcinoma, the pancreatic body width decreased as tumor size increased and uniform atrophy with continuous beading duct was common in large carcinomas. The H/B ratio in small carcinomas (less than 2 cm), however, was significantly smaller than normal (p less than 0.05) and an enlarged pancreatic body was seen in 55 percent of these cases. The pancreatic body width in focal inflammatory masses was large compared to that in carcinomas of comparable size; the H/B ratio (1.57) was close to normal and the duct caliber to gland width ratio was low (0.16), even with large lesions. Non-uniform pancreatic body with discontinuous duct was most commonly associated with pseudocyst. Characterization of the CT appearance of secondary changes in the pancreatic body may help to improve the diagnosis of pancreatic head mass.