Abstract
BACKGROUND: Ductal communication is a critical discriminator for differentiating intraductal papillary mucinous neoplasms (IPMNs) from other pancreatic cystic neoplasms. This study evaluated dual-layer spectral detector computed tomography (DLCT)-derived virtual monoenergetic images (VMIs) for displaying IPMN-duct communication compared to conventional polyenergetic images (PEIs) and magnetic resonance cholangiopancreatography (MRCP). METHODS: A total of 35 patients with IPMNs from August 2021 to September 2023 were enrolled in this cross-sectional study. PEIs and VMIs (40/50/60/70 keV) were reconstructed at arterial phase (AP) and portal venous phase (PVP). Quantitative metrics [attenuation difference (AD), signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR)] for pancreatic parenchyma, lesions, and ducts were measured. Two radiologists independently assessed qualitative parameters (5-point Likert scales) and duct communication. Statistical analyses included analysis of variance (ANOVA) test, Friedman test, inter-reader agreement (kappa), and McNemar's test. RESULTS: Quantitative analysis demonstrated that VMI 40 keV achieved the highest AD, SNR, and CNR for lesions/ducts (P<0.001 vs. PEI), with lesion AD at AP increasing >130% [224.1 vs. 94.8 Hounsfield units (HU); P<0.001]. VMI 40-50 keV provided significantly higher AD and CNR than VMI 60-70 keV (P<0.01). Qualitatively, VMI 40 keV scored optimally (median =5 across all parameters; P<0.001 vs. PEI) with excellent inter-reader agreement (κ=0.78-0.81). DLCT at VMI 40 keV displayed ductal communication in all 30 patients (100%), whereas MRCP demonstrated 28/30 cases (93.3%, P=0.500). CONCLUSIONS: VMI 40-50 keV significantly improved quantitative and qualitative image quality in the display of IPMN-duct communication over PEI and higher-keV VMIs, achieving diagnostic equivalence to MRCP. This supports DLCT as a practical alternative when MRCP is contraindicated or unavailable.