Prevalence of incidental pancreatic cysts in the adult population on MR imaging.

Objectives: The reporting of incidental pancreatic cystic lesions on cross-sectional imaging studies has dramatically increased over the last few years. The prevalence of incidental pancreatic cysts in the adult population, however, is unknown. The aim of our study was to determine the prevalence of incidentally detected pancreatic cysts in the adult population undergoing abdominal magnetic resonance (MR) imaging.

Methods: MR imaging examinations of 616 consecutive patients obtained between January 2001 and February 2002 were retrospectively reviewed by two radiologists and the following information was recorded: the total number of pancreatic cysts; the maximum diameter, location, and characteristics of the largest cyst; documentation of the cyst(s) within the radiology report; and characteristics of the cyst(s) at imaging follow-up.

Results: Incidental pancreatic cysts were present in 13.5% (83/616) of patients, with 60% of the cysts being solitary, and 88% of the cysts being simple. Largest cyst mean and median diameters were 7.4 mm (2-24 mm) and 6 mm, respectively. Both the prevalence of pancreatic cysts and the mean size of the largest cyst increased with age (P=0.007, r=0.893 and P=0.003, r=0.929, respectively). Only 31% (26/83) of incidental pancreatic cysts were documented in the radiology report. The mean size of reported pancreatic cysts was larger than those cysts that were not reported (P<0.001).

Conclusions: The prevalence of incidentally detected pancreatic cysts on MR imaging is 13.5%, and increases with age. A majority of these cysts are not reported on MR imaging studies.