Lower Interobserver Reliability for Nondimensional Intracystic Features Among Abdominal Radiologists for Characterizing Intraductal Papillary Mucinous Neoplasms Using Magnetic Resonance Imaging

Objectives Current guidelines recommend magnetic resonance imaging (MRI)/magnetic resonance cholangiopancreatography (MRCP) for risk stratification of intraductal papillary mucinous neoplasms (IPMNs). We assessed the interobserver agreement among radiologists in evaluating and risk stratifying IPMNs. Methods This single-center study evaluated 30 patients with IPMNs who had undergone MRI/MRCP, endoscopic ultrasound, and/or surgical resection. Six abdominal radiologists evaluated the MRI/MRCPs to document multiple parameters. The analysis applied Landis and Koch κ interpretation for categorical variables and intraclass correlation coefficient (r) for continuous variables. Results Radiologists demonstrated almost perfect agreement for location (κ = 0.81, 95% confidence interval [CI], 0.74-0.87), size (r = 0.95; 95% CI, 0.89-0.98), and main pancreatic duct diameter (r = 0.98; 95% CI, 0.96-0.99). Substantial agreement was observed for communication with the main pancreatic duct (κ = 0.66; 95% CI, 0.57-0.75) and classification of IPMN subtype (κ = 0.77; 95% CI, 0.67-0.86). Presence of intracystic nodules (κ = 0.31; 95% CI, 0.21-0.42) and wall thickening (κ = 0.09; 95% CI, -0.01 to 0.18) reached only fair and slight agreement, respectively. Conclusions Although MRI/MRCP is excellent in the evaluation of spatial aspects, there is lower reliability for nondimensional characteristics of IPMNs. These data support guideline-recommended complementary evaluation of IPMNs with MRI/MRCP and endoscopic ultrasound.