Respiratory variation of the diameter of the pancreatic duct on sonography.

Abstract

The objective of this study was to assess the prevalence of a 1-mm or greater increase in the diameter of the pancreatic duct during deep inspiration in patients without pancreatic disease. A retrospective review was performed of normal findings on pancreatic sonograms of 25 consecutive lean patients without pancreatic disease who were capable of taking deep breaths. The anteroposterior diameter of the pancreatic duct in the body of the gland was measured at end-expiration and end-inspiration. A significant change was defined as a 1-mm or greater difference between the end-inspiratory and end-expiratory diameters for at least two of three consecutive breaths. Seven patients (28%) had a significant increase in the diameter of the pancreatic duct at end-inspiration. These included four patients (16%) in whom the diameter of the duct was less than or equal to 2.5 mm (i.e., normal) at end-inspiration and three patients (12%) in whom the diameter of the duct was greater than 2.5 mm at end-inspiration. The diameter of the pancreatic duct can increase during deep inspiration in some adults without pancreatic disease. This finding should be borne in mind as a potential pitfall during pancreatic sonography.