Suspected chronic pancreatitis with normal MRCP: Findings on MRI in correlation with secretin MRCP

Purpose: To review pancreatic MRI findings and their relationship with estimated pancreatic exocrine function on secretin-stimulated MR cholangiopancreatography (S-MRCP) in patients with clinically suspected chronic pancreatitis and normal baseline MRCP findings. Materials and Methods: MRI findings of 26 patients with normal pancreatic duct diameter and without side branch ectasia on MRCP were evaluated. A single radiologist assessed pancreatic size, pancreatic signal intensity ratio (SIR), and arterial enhancement ratio (A/V) at head, body, and tail of the pancreas on T-1-weighted fat-suppressed and serial contrast-enhanced images at a single session. Combined findings were graded with a composite score. Serial S-MRCP was performed at the same session with standard MRI. Correlation and differences between MRI findings and associated grade of duodenal filling (I)F) or the degree of pancreatic duct caliber change (PDC) were analyzed. Results: Seven patients revealed normal and 19 patients abnormal MRI findings. Significant correlation was present between the degree of DF and mean values of pancreatic size (r = 0.748), SIR (r = 0,610), A/V (r = 0.466), composite score (r = 0.833), and PDC (r = 0.554) separately. PDC correlated with SIR (r = 0.413) and composite score (r = 0.452), but not with A/V or pancreatic size. Significant differences were present between normal and abnormal DF grades in terms of mean values of associated findings of size (P = 0.001), SIR (P = 0.008), A/V (P = 0.019), and PDC (P = 0.001). Conclusion: Patients with clinically suspected chronic pancreatitis and normal MRCP findings may have a spectrum of MRI findings that correlate with the estimated pancreatic exocrine insufficiency on S-MRCP with the increasing number of combined findings.