Contrast enhanced CT and MRI interchangeably reflect tumor characteristics in murine pancreatic cancer

Contrast-enhanced computed tomography (CE-CT) and dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) are commonly used for tissue characterization, with CE-CT typically preferred in human studies and DCE-MRI in murine models. This raises the question of comparability of intra-and cross-species study results, as techniques differ and signal intensities following contrast agent (CA) administration reflect a complex interplay of systemic physiology and local tissue characteristics. This pilot study compares in vivo mean values of regions of interest (ROIs) obtained from CE-µCT (NanoScan^® SPECT/CT) and 7 T DCE-MRI (Agilent Discovery MR901 magnet with Bruker AVANCE III HD electronics) and evaluates ex vivo CA distribution using laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MSI). A genetically engineered mouse model of pancreatic ductal adenocarcinoma (PDAC) served as the experimental system. Image-derived regional mean Hounsfield unit (HU) and area under the curve at 60 s (AUC₆₀) values were correlated with mean local iodine (iomeprol) and gadolinium (gadopentetate dimeglumine) concentrations. Semi-quantitative analysis of HU and AUC₆₀ enabled excellent distinction of histologically defined tumor regions with low versus high tumor cellularity (p < 0.0001 for both). A strong intermodal correlation was observed between regional HU and AUC₆₀ values (r = 0.91, 95% CI = 0.78-0.97), as well as between iodine and gadolinium ion concentrations (r = 0.86, 95% CI = 0.55-0.96). These findings demonstrate that CE‑µCT and DCE‑MRI show comparable trends as prognostic imaging biomarkers of tumor cellularity in murine PDAC, underscoring their complementary value for cross‑species translational imaging research.