Objectives: Secretin-stimulated magnetic resonance imaging (s-MRI) is the best validated radiological modality assessing pancreatic exocrine secretion. In this prospective observational study, we compare the diagnostic accuracy of s-MRI for exocrine pancreatic failure due to different pancreatic diseases and healthy controls.
Methods: We performed s-MRI in 21 cystic fibrosis (CF) patients, 78 patients with chronic pancreatitis (CP) and 20 healthy controls. Exocrine failure was defined by fecal elastase-1 of less than 200 μg/g or bicarbonate concentration from endoscopic secretin test of less than 80 mmol/L.
Results: Eleven CF and 61 CP patients were exocrine insufficient. Insufficient CF patients had lower s-MRI volume output compared with all other groups (P < 0.05). Insufficient CP patients had reduced volume output compared with controls and sufficient CF (P < 0.05). Secretin-stimulated MRI yielded overall accuracy of 0.78 (95% confidence interval [CI], 0.70-0.86) for exocrine failure. When divided according to etiology, the test yielded accuracy of 0.95 (95% CI, 0.90-1) in CF and 0.73 (95% CI, 0.64-0.82) in CP.
Conclusions: The accuracy of s-MRI volume output measures to diagnose exocrine failure was higher in CF than in CP. Differences in s-MRI volume output in patients with exocrine failure may be due to different etiological and pathogenic mechanisms in CF and CP.