The apparent increase in the prevalence of incidental pancreatic cysts in recent years may be tied to improvements in MRI scanning technology, results of a study suggest.
Researchers conducted a retrospective analysis of data from 500 patients who underwent an MRI for nonpancreatic indications at a single center between 2005 and 2014; 50 were sampled from each year in chronological order.
A total of 208 patients (41.6%) were found to have an incidental cyst, of which less than a quarter were described in the original MRI report, according to a paper published online in Clinical Gastroenterology and Hepatology.
Analysis showed a very strong association between the type of imaging hardware and software, and the presence of cysts; older hardware found pancreatic cysts in 30.3% of patients and the newest hardware found cysts in 56.3% of patients.
However, MRI field strength was not associated with the frequency of lesion discovery (Clin Gastro Hepatol. 2015 Sep 11. doi: 10.1016/j.cgh.2015.08.038).
Most cysts were relatively small, with a median size of 4 mm. Nearly half of the patients with a cyst only had one described.
Nearly two-thirds of these cysts (62%) had an uncertain diagnosis, but 35% of patients were diagnosed with an intraductal papillary mucinous neoplasm, and one patient showed radiologic evidence of subacute pancreatitis.
When compared to the rest of the cohort, individuals with pancreatic cysts were more likely to be older, have diabetes mellitus, or have a personal history of cancer, particularly nonmelanoma skin cancer and hepatocellular carcinoma.
“Our study demonstrates the relationship between the higher trend of incidental pancreatic cysts observed in the recent years and the improvements in the technical features of MRIs,” wrote Dr. Maria Moris and colleagues from the Mayo Clinic, Jacksonville.
The authors said the real prevalence of pancreatic cystic lesions is estimated to range from 0.2% to 44.7%.
Their finding of a prevalence of 41.6% was higher than that found in similar imaging studies, but the authors suggested some of this may be due to the lack of a size cutoff in their study, as opposed to a 5-mm cutoff used in one earlier study that found a prevalence of 10%.
“Moreover, we believe that we may have even underestimated the real prevalence because of the absence of magnetic resonance cholangiopancreatography sequences (only 19% of the examinations), and the lack of 3-T studies (6% of the MRIs),” they wrote.
The median size of the lesions was lower than those found in previous studies.
“This smaller size was unexpected because, as a result of the exclusion criteria applied, the technical features of the MRIs were not the most specific for [pancreatic cystic lesion] PCL visualization,” the authors wrote, suggesting that this may have been due to the radiologist’s experience in this field.
The study was funded by the Joyce E. Baker Foundation for Research at Mayo Clinic in Jacksonville. One author disclosed grants or travel support from Olympus, Boston Scientific, and Cosmo Pharmaceuticals. There were no other conflicts of interest declared.
Review the AGA guideline on the management of asymptomatic pancreatic neoplastic cysts at http://www.gastro.org/guidelines/2015/5/29/pancreatic-cysts.