Photon-counting computed tomography: a revolution in cardiac imaging

Photon-counting detector computed tomography (PCD-CT) is an emerging advanced CT technology that differs from conventional energy-integrating detector CT (EID-CT) scanners in its ability to directly convert incident X-ray photon energies into electrical signals. Since its commercial market introduction in 2021, several studies have identified advantages of this new technology in the field of cardiovascular imaging, including improved image quality due to an enhanced contrast-to-noise ratio, superior spatial resolution, reduced artefacts, and a reduced radiation dose. Nonetheless, radiation exposure with PCD-CT can vary depending on the acquisition mode and protocol used, highlighting the importance of tailored optimization in clinical practice. In particular, this new technology appears feasible in patients with a high plaque burden independent of morphology, unravelling new phenotypes of plaque, in patients with stents due to the improved visualization of the coronary in-stent lumen, potentially expanding the scope of CT. Early studies and clinical experience support these potential applications of PCD-CT in cardiovascular diagnostics, suggesting workflow optimization and improved patient management. In this review, the authors aim to describe the role of PCD-CT not only in the exclusion of coronary artery disease, grading of coronary stenosis and plaque imaging, but also in evaluation of cardiac chambers and myocardium for tissue characterization trying to understand whether PCD-CT has yet led to a true revolution and significant progress in cardiovascular imaging.