Normal pancreatic exocrine function does not exclude MRI/MRCP chronic pancreatitis findings

Objective: Abnormal pancreatic function tests have been reported to precede the imaging findings of chronic pancreatitis. Magnetic resonance imaging (MRI) with magnetic resonance cholangiopancreatography (MRCP) is increasingly accepted as the primary imaging modality for the detection of structural changes of early mild chronic pancreatitis. The aim of this Study was to evaluate MRI/MRCP findings in patients with symptoms consistent with chronic pancreatitis who have normal Secretin Endoscopic Pancreatic Function test. Methods: A retrospective study of 32 patients referred for evaluation of chronic abdominal pain consistent with chronic pancreatitis and reported normal standard abdominal imaging (ultrasound, computed tomography, or MRI). All patients underwent Secretin Endoscopic Pancreatic Function testing and pancreatic MRI/MRCP at our institution. We reviewed the MRI/MRCP images in patients who had normal Secretin Endoscopic Pancreatic Function testing. MRI/MRCP images were assessed for pancreatic duct morphology, gland size, parenchymal signal and morphology, and arterial contrast enhancement. Results: Of the 32 patients, 23 had normal Secretin Endoscopic Pancreatic Function testing, and 8 of them had mild to marked spectrum of abnormal MRI/MRCP findings that were predominantly focal. Frequencies of the findings were as follows: pancreatic duct stricture (n = 3), pancreatic duct dilatation (n = 3), side branch ectasia (n 4), atrophy (n = 5), decreased arterial enhancement (n = 5), decreased parenchymal signal (n = 1), and cavity formation (n = 1). The remaining 15 patients had normal pancreatic structure on MRI/MRCP. Conclusions: Normal pancreatic function testing cannot exclude abnormal MRI/MRCP especially focal findings of chronic pancreatitis. Further studies needed to verify significance of these findings and establish MRI/MRCP imaging criteria for the diagnosis of chronic pancreatitis.