Photon-counting detector computed tomography for evaluation of coronary artery disease in older adults

Coronary computed tomography angiography (CCTA) in older adults is often limited by heavy coronary artery calcification and associated blooming artifacts. Photon-counting detector CT (PCD-CT) offers higher spatial resolution and reduced artifacts compared with conventional energy-integrating detector CT (EID-CT). We sought to investigate diagnostic performance and clinical impact of PCD-CT in older adults.

This retrospective, single-center study included consecutive individuals who underwent CCTA between 2022 and 2023. Patients were grouped by scanner type (EID-CT or PCD-CT) and age group (older [≥70 years] or younger [<70 years]). The rates of indeterminate readings, referral to invasive coronary angiography (ICA), and ICA without revascularization were compared. Among patients referred to ICA after CCTA, the diagnostic performance of CCTA in detecting obstructive CAD was evaluated using quantitative coronary angiography (QCA) as the reference standard.

Among older adults undergoing CCTA (n ​= ​1571), the rate of indeterminate CCTA findings was lower in the PCD-CT group compared to the EID-CT group (8.8 ​% vs. 14.6 ​%; P ​< ​0.001). PCD-CT was associated with lower rates of ICA referral (16.7 ​% [143/854] vs. 22.6 ​% [162/717]; P ​= ​0.004) and ICA without revascularization (9.1 ​% [78/854] vs. 14.1 ​% [101/717]; P ​= ​0.002) compared with EID-CT. Among 587 vessels in patients referred for ICA, PCD-CT (n ​= ​289) showed higher vessel-level diagnostic accuracy than EID-CT (n ​= ​298) (95.5 ​% vs. 90.3 ​%; P ​= ​0.02). When comparing between age groups, the vessel-level diagnostic accuracy of PCD-CT was similar among older (n ​= ​289) and younger adults (n ​= ​471) (95.5 ​% vs. 96.8 ​%, p ​= ​0.43).

In older patients aged ≥70 years, PCD-CT was associated with improved diagnostic accuracy, fewer indeterminate findings, and consequently, reduced unnecessary invasive testing compared with EID-CT.