Single session photon counting CT protocol for simultaneous screening of coronary and carotid artery disease and lung pathology

Background Cardiovascular and pulmonary diseases remain leading causes of death, yet population-wide screening is limited by the cumulative burden of three separate computed-tomography (CT) examinations. Photon-counting CT (PCCT) permits spectral, ultra-high-resolution imaging at reduced dose, offering an opportunity to consolidate studies. Purpose To develop and evaluate a single-session PCCT protocol that simultaneously assesses coronary and carotid arteries, thoracic structures, lung parenchyma and myocardial tissue within one breath-hold. Methods The protocol combines four sequential acquisitions: (i) non-contrast coronary artery calcium scoring, (ii) 0.2-mm ultra-high-resolution coronary CT angiography (70 kVp, retrospective ECG-gating), (iii) a <3-s high-pitch helical sweep (pitch 3.4) from diaphragm to orbital floor, and (iv) 5-min delayed ECG-triggered late-iodine enhancement of heart and breasts. A weight-adapted triple-phase injection delivers 0.48 g I/kg contrast. Technical feasibility and diagnostic image quality were tested in 102 asymptomatic adults aged 45 to 75 years with diabetes from at least 10 years, current or previous smokers, or with a Framingham risk score ≥10%, evaluated as part of an ongoing study. Results All examinations were completed within 5 min of table time and a 18-20 s breath-hold. The cumulative iodine dose was 0.48 gI/kg with iomeprol 400 and 0.44 gI/kg with iopromide 370. The median effective dose was 794 mSv with an interquartile interval of 672 to 1,116 mSv. The calcium score imaging accounted for 92 mSv (75-111), the coronary artery angiogram for 503 mSv (396-773), the lung and carotid scan for 158 mSv (127-190), and the late acquisition for 67 mSv (51-102). The protocol produced diagnostic image quality in all cardiac, vascular and pulmonary territories. Conclusion A single breath-hold PCCT protocol can replace three conventional CT examinations, providing comprehensive cardio-thoracic and oncologic information at a radiation dose comparable to stand-alone coronary CTA. This approach may streamline preventive imaging for high-risk groups.Acquisition protocol