Photon-Counting Detector CT in Cardiothoracic Imaging: AJR Expert Panel Narrative Review

The implementation of photon-counting (PCD) CT has led to substantial technologic improvements over conventional energy-integrated detector (EID) CT. These advances include better spatial and contrast resolution, intrinsic spectral information, and potential for reductions in radiation doses and contrast media volumes. Since the clinical introduction of PCD CT, numerous studies have been performed to investigate the advantages and potential impact brought by this new technology for various clinical scenarios with respect to cardiothoracic imaging. For example, PCD CT offers improved visualization of pulmonary and cardiac anatomy and allows dose reduction in the assessment of pulmonary vasculature, nodules, emphysema, and interstitial lung diseases. PCD CT also improves visualization of coronary plaque and stents, provides more accurate assessment of coronary stenoses, and facilitates myocardial tissue characterization. The faster data acquisition enabled by PCD CT additionally aids cardiothoracic evaluation in pediatric and/or dyspneic patients. This AJR Expert Panel Narrative Review explores these state-of-the art cardiothoracic applications of PCD CT considering supporting evidence, technical features, protocols, and areas of greatest potential clinical benefit. Ongoing implementation challenges and remaining research priorities that warrant attention to support the integration of PCD CT into standard cardiothoracic imaging practice are highlighted.