Agreement between magnetic resonance cholangiopancreatography and endoscopic retrograde cholangiopancreatography limited in diagnosing anatomic pancreatic variants

1. Based on radiologists’ blinded review of 74 paired scans, agreement between magnetic resonance cholangiopancreatography (MRCP) and endoscopic retrograde cholangiopancreatography (ERCP) was moderate for the diagnosis of pancreatic duct variants and for specific diagnoses.

2. Concordance among the group of reviewers was moderate to substantial.

Evidence Rating Level: 2 (Good)

Study Rundown: Pancreas divisum is a relatively common anatomic variant that is often asymptomatic. However, this and other variants in pancreatic ductal anatomy may be clinically significant in childhood or may point to a broader diagnosis, meaning that detailed and accurate identification and characterization of pancreatic variants is critical. This study aimed to compare the utility of MRCP to ERCP, which is invasive but remains the diagnostic standard. 74 pediatric patients at a single center who had suggested or identified abnormalities on either ERCP or magnetic resonance imaging (MRI) and underwent both ERCP and MRCP were included. Three blinded pediatric radiologists reviewed the MRCP scans. Agreement between individual reviewers and the ERCP standard was moderate for specific diagnoses and for the presence of any abnormality and fair for the presence of pancreas divisum. Because of its pre-selected patient population, this study does not reflect the sensitivity or specificity of MRCP. It does strongly indicate, however, that radiologists’ review of MRCP scans alone would result in different determinations on the presence of pancreatic variants than ERCP in a significant number of cases. This suggests that MRCP has major limitations in the setting of suspected pancreatic ductal variants as a tool for either identification or diagnosis of specific variants.

Click to read the study in the Journal of Pediatrics

Relevant Reading: Identification and management of pancreas divisum

 In-Depth [retrospective cohort]: 76% of patients had a duct abnormality based on the ERCP reference standard. 73% of these patients had pancreas divisum. Patients with annular pancreas and anomalous pancreaticobiliary junction were included. MRCP protocols with and without use of secretin were also included. Fleiss’s Kappa test was used to assess agreement. Overall agreement between reviewers on MRCP sequence quality was fair (κ = 0.31, 95% confidence interval 0.2-0.42, p<0.0001). The κ values for agreement between individual reviewers and the ERCP standard were 0.56 (0.49-0.64) for exact diagnosis and 0.48 (0.28-0.67) for the presence of any abnormality. Agreement between reviewers was moderate for both exact diagnosis (κ = 0.56, 0.49-0.64) and the presence of any abnormality (0.48, 0.28-0.67), and substantial for the presence of pancreas divisum (0.7, 0.62-0.79). Logistic regression showed no significant predictive effects of patient age, interval between MRCP and ERCP, MRCP quality, presence of annular pancreas, or secretin use on individual reviewers. MRCP quality was associated with higher agreement on the presence of any abnormality (odds ratio = 13, p = 0.039).

Image: PD

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