Screening coronary and carotid Atherosclerosis and lung cancer by Computed Tomography Angiography with photon-counting detector technology: the ACTA study

Background Photon-counting computed tomography (PCCT) offers significant advantages over conventional CT systems, including improved spatial resolution, reduced imaging noise, intrinsic spectral capabilities, and radiation dose. Its role in cardiovascular and oncologic risk assessment is still under investigation. Purpose We launched a prospective screening program for individuals at elevated cardiovascular risk using PCCT. The acquisition protocol permits simultaneous evaluation of the coronary and carotid arteries, lung parenchyma, and other thoracic and cervical structures. This report summarises findings from the first 100 of the planned 560 participants. Methods General practitioners referred adults aged 45–75 years who had no angina, no history of coronary artery disease, and no current indication for coronary imaging but met at least one of the following criteria: 1) type 2 diabetes of more than 10 years’ duration, 2) current or former smoking within the past 15 years, or 3) a Framingham Hard Coronary Disease Risk Score ≥10%. The PCCT protocol evaluated coronary and carotid atherosclerosis, lung nodules, and other incidental findings. After imaging, each patient received a consultation focused on optimising therapy and further diagnostic exams, as appropriate. Results A total of 102 consecutive participants were scanned (median age 62 years, interquartile range 54-68; 46% women, 29% diabetic, 86% current or previous smoker) (Figure 1). Subclinical coronary atherosclerosis was identified in 69%, with ≥1 stenosis >50% in 9% (Figure 2). When excluding patients with any history of extra-coronary atherosclerosis (27%), 60% exhibited coronary disease. In the whole cohort, 44% displayed carotid plaques, and 29% bilateral plaques. Carotid plaques were found in 25% of subjects without coronary plaques. Lung nodules requiring CT follow-up were detected in 23% and previously unrecognised emphysema in 21% of participants. Incidental findings included thyroid nodules in 18% and breast nodules in 26% of women. Downstream exams included myocardial perfusion scintigraphy in 16% and direct coronary angiography in 1%. As for incidental findings, one patient was diagnosed with follicular thyroid carcinoma and another one with lung carcinoid. Therapeutic optimisation led to new initiation of antiplatelet therapy in 58% and lipid-lowering drugs in 46%, with titration of existing lipid-lowering regimens in a further 20%. Conclusions One-stop photon-counting CT screening of coronary and carotid arteries together with lung parenchyma is feasible and reveals a high prevalence of subclinical disease in middle-aged individuals at elevated cardiovascular risk. The findings translated into immediate changes in preventive pharmacotherapy and selective referral for further cardiac or oncologic work-up. Ongoing enrolment and follow-up will clarify the cost-effectiveness and prognostic impact of this PCCT-based screening strategy.Risk factors in men and women Patterns of coronary artery disease