Randomized Prospective Trial on the Cost-Effectiveness of Photon-Counting CT Versus Energy-Integrating Detector CT in Suspected Chronic Coronary Syndrome

Overview

Coronary artery disease (CAD) is a leading cause of morbidity and mortality worldwide. Coronary computed tomography angiography (CCTA) is recommended as a first-line imaging test in patients with suspected obstructive CAD. However, conventional energy-integrating detector CT (EID-CT) has limited specificity, particularly in patients with a high coronary calcification burden, because blooming and beam-hardening artifacts can lead to stenosis overestimation and potentially unnecessary downstream diagnostic testing or invasive coronary angiography (ICA). Photon-counting detector CT (PCD-CT) provides higher spatial resolution, reduced electronic noise, and decreased blooming artifacts compared with conventional EID-CT. These technical advantages may improve the diagnostic assessment of coronary stenoses, reduce false-positive findings, and consequently decrease the need for additional functional testing and unnecessary ICA. Improved diagnostic accuracy may also influence treatment decisions, patient outcomes, and healthcare resource utilization. This study aims to compare PCD-CT and EID-CT CCTA for the detection and quantification of CAD in a real-world clinical setting. In addition to diagnostic performance, the study will evaluate the impact of the two imaging strategies on subsequent diagnostic and therapeutic management, healthcare resource utilization, costs, and clinical outcomes. Patients will be followed from the date of the index CCTA examination for up to two years. Healthcare costs will be estimated using national and regional reimbursement tariffs of the Italian public healthcare system.

Coronary artery disease (CAD) is one of the leading causes of morbidity and mortality worldwide. Coronary computed tomography angiography (CCTA) is the first-line imaging test for patients with suspected obstructive CAD. However, its main limitation is the relatively low and variable specificity and positive predictive value across different studies, especially in patients with high calcified coronary plaque burden due to blooming and beam-hardening artifacts that can lead to the overestimation of the degree of coronary artery stenosis, reduced specificity, and, consequently, increased rate of downstream functional imaging tests or diagnostic invasive coronary angiography (ICA). Photon-Counting Detector-Computed Tomography (PCD-CT) represents an important evolution in the CT technology introduced in the clinical practice in the last years, but still with a limited diffusion due to the high purchase cost of the scanners. In the context of CAD evaluation, the two modalities differ in spatial resolution, blooming artifacts, and electronic noise levels, representing distinct technical approaches to diagnostic imaging accuracy. Recent studies demonstrate that these technical advantages may translate into a higher diagnostic accuracy of PCD-CT in differentiating functional significant stenosis from non-significant stenosis, with a lower rate of false positive results and higher overall diagnostic accuracy. This increase in diagnostic accuracy with reduction in false positive results may be associated to a reduction in downstream functional tests performed after a PCD-CT CCTA compared with an EID-CT CCTA, as well as a decrease in unnecessary invasive coronary angiographies resulting from false-positive CCTA findings. Moreover, a more precise diagnosis may also translate into more appropriate treatment decisions and potential prognostic benefits. These potential advantages may ultimately lead to a reduction in downstream healthcare expenditures when using PCD-CT CCTA. However, the impact of these differences on clinical decision-making and healthcare resource utilization remains to be fully established in real-world settings. Thus, the investigator proposes to compare the diagnostic performance of PCD-CT performed with a NAEOTOM Alpha photon-counting CT scanner (Siemens Healthineers, Germany) and EID-CT performed with a SOMATOM Definition Flash (Siemens Healthineers, Germany) in the identification and quantification of CAD. Moreover, the investigator aims to assess the cost-effectiveness and the prognostic impact of PCD-CT compared to EID-CT in CAD diagnosis and management according to 2024 ESC Guidelines, collecting all index data related to the patients' clinical history from the day of the CCTA examination up to two years afterward, and estimating healthcare costs according to the national and regional reimbursement tariffs of the public health system for all healthcare services delivered.