Diagnostic performance of Photon-counting CT angiography in peripheral artery disease compared to DSA as gold standard

Background: Photon-counting (PC) CT has the potential to improve diagnostic confidence and image quality of CT angiography (CTA) in patients with peripheral artery disease (PAD).

Purpose: To retrospectively evaluate the diagnostic performance of Photon-counting CT angiography for the assessment of stenotic disease in patients with PAD compared to digital subtraction angiography (DSA) as gold standard.

Materials and methods: All patients undergoing PC CTA followed by DSA between November 2021 and November 2023 were included in this institutional review board approved HIPAA compliant retrospective analysis. The arterial vasculature of the lower extremity was divided into 10 segments from the iliac vasculature to the calf arterial vasculature. The images were evaluated independently by two experienced readers. Inter-reader agreement was determined using Cohen's kappa coefficient (κ). Sensitivity, specificity, positive (PPV) and negative predictive values (NPV) as well as accuracy were calculated for PC CTA and PC pure lumen reconstruction compared to DSA as gold standard.

Results: 109 patients (mean age 74.68 ± 11.10 years; 77 males, 32 females) were included in the retrospective analysis. PC pure lumen reconstructions was available for 91 patients (83 %). A total of 933 vascular segments for PC CTA and 780 vascular segments for PC pure lumen reconstruction were evaluated. Good to perfect inter-reader agreement was found for PC CTA (κ = 0.791) and for PC pure lumen reconstruction (κ = 0.829). Sensitivity, Specificity and accuracy for PC CTA were 91 %; 95 % and 93 %, respectively. Sensitivity, Specificity and accuracy for PC pure lumen reconstruction were 85 %, 89 % and 88 %, respectively.

Conclusion: Photon-counting CTA demonstrates high sensitivity and specificity for the detection and diagnosis of stenotic lesions in PAD. PC non-calcium reconstruction does not further increase the accuracy compared to PC CTA.