Vessel Dependent Myocardium at Risk on Coronary CT Angiography Validated Against Dynamic CT Myocardial Perfusion...

Accurate assignment of myocardial territories supplied by individual coronary arteries on coronary CT angiography (CCTA) is essential for estimating myocardium at risk. Validation of coronary-based myocardial segmentation has been limited by co-registration challenges with perfusion imaging as the reference standard. By reconstructing coronary angiograms directly from the dynamic CT myocardial perfusion imaging (CT-MPI), we ensured inherent co-registration between coronaries and perfusion maps. Vessel-specific myocardial territories were assigned using a minimum cost path (MCP) and validated against MBF-derived perfusion defects from the same acquisition. In 22 patients with 27 well-defined ischemic territories MCP-assigned territories showed moderate spatial overlap with CT-MPI-derived hypoperfusion (Dice coefficient 0.72 ± 0.13) with strong surface area correlation (r = 0.81, p < 0.001). Agreement was highest in the left anterior descending (LAD) territory. MCP-based tessellation using inherently co-registered CCTA and CT-MPI enables accurate vessel-specific myocardium-at-risk assessment and offers a promising platform for anatomical-functional integration in coronary disease.