Photon-counting computed tomography in coronary artery bypass grafting planning and follow-up: a narrative review of a high-resolution adjunct to invasive angiography.

BACKGROUND AND OBJECTIVE: Conventional coronary imaging modalities used for coronary artery bypass grafting (CABG) planning-such as invasive angiography and energy‑integrating detector computed tomography-are limited by spatial resolution, blooming artifacts, and reduced accuracy in heavily calcified or stented segments. Photon‑counting computed tomography (PC‑CT) introduces ultrahigh spatial resolution and spectral imaging capabilities that may overcome these limitations and improve preoperative and postoperative coronary assessment. This study aimed to evaluate the current technical capabilities and clinical performance of PC‑CT in CABG planning and postoperative graft assessment, and to explore its potential future applications as a non‑invasive imaging strategy. METHODS: A targeted review of studies published between 2018 and 2025 was performed using search terms related to PC-CT, coronary imaging, plaque morphology, stent visualization, distal target assessment, and bypass graft imaging. Feasibility studies, phantom experiments, technical evaluations, single-center clinical studies, and early postoperative imaging reports were included based on relevance to surgical planning and graft assessment. KEY CONTENT AND FINDINGS: PC-CT demonstrated higher spatial resolution, reduced blooming artifacts, and improved contrast-to-noise performance compared with conventional computed tomography (CT). These features enhanced visualization of calcified lesions, distal coronary branches, and stented segments. Studies reported improved lumen assessment in calcified vessels, more detailed plaque characterization through spectral imaging, and clearer delineation of stent structures with correlation to invasive imaging. Early postoperative work showed detailed visualization of bypass conduits and anastomoses. Evidence remains limited by small sample sizes, single-center designs, and variability in acquisition and reconstruction protocols. CONCLUSIONS: PC-CT provides improved coronary imaging performance relevant to CABG planning and postoperative graft assessment. Its enhanced spatial resolution and spectral capabilities support more accurate evaluation of stenosis, plaque morphology, distal targets, and stented segments. Broader clinical validation, standardized protocols, and increased scanner availability are needed before PC-CT can be adopted as a routine non-invasive alternative to invasive angiography.