EXPRESS: High-resolution three-dimensional characterization of clot evolution in experimental intracerebral hemorrhage using diceCT.

BACKGROUND: MRI is widely used to monitor experimental intracerebral hemorrhage (ICH), but T2*-weighted lesion volume may reflect both clot components and blood degradation products during hematoma evolution. We utilized diffusible iodine-based contrast-enhanced CT (diceCT) to examine diceCT-visible clot changes in relation to MRI-defined lesions. METHODS: ICH was induced in 102 mice via collagenase or autologous blood infusion. DiceCT was performed at 4 hours, 1, 3, 7 and 28 days post-ICH. In paired MRI-diceCT cohorts, diceCT-visible clots were compared with T2*-weighted MRI lesions. RESULTS: DiceCT enabled volumetric assessment of clot components and erythrolysis-associated intralesional hypodense regions after ICH. High-resolution imaging revealed vascular-associated clot extensions toward the brain surface. Multimodal analysis revealed an early shift in hemorrhagic lesion composition: the fraction of the MRI-defined T2* lesion represented by diceCT-visible clot decreased markedly by day 7 (16.92% in the autologous blood model and 2.59% in the collagenase model). CONCLUSION: DiceCT provides high-resolution ex vivo visualization of clot structures after experimental ICH. Combined MRI-diceCT analysis indicates that MRI-defined lesions and diceCT-visible clot structures diverge over time, supporting the use of complementary imaging readouts to characterize hematoma evolution and persistent blood-derived signals after ICH.