Evaluation of an Integrated Photon-Counting Detector CT Angiography Reconstruction Protocol for Carotid Artery Stents

To evaluate an integrated protocol and to improve image quality for follow-up after carotid artery stenting (CAS) using photon-counting CT (PCD-CT) angiography.

Patients who underwent CT angiography (CTA) after CAS using PCD-CT in 2023-2025 were included. We predefined an integrated reconstruction protocol that combines multiple reconstruction parameters into a clinically applicable configuration under practical feasibility constraints, and that can be consistently applied to all cases. Reconstruction parameters were as follows: slice thickness, 0.4mm; field-of-view, 120mm; kernel, Qr56; iterative reconstruction, QIR3; virtual monoenergetic image, 55keV, metal artifact reduction algorithm, off. We quantitatively measured in-stent luminal contrast-to-noise ratio (CNR), stent edge rise slope (ERS), and in-stent luminal artifact index inside stents (AI). We qualitatively assessed in-stent luminal image quality (IQ), stent edge sharpness, and in-stent luminal noise. We compared integrated protocol to our institution conventional protocol. Linear mixed-effects models were used for statistical analyses.

31 patients (median 77 years [71-79], 31 men) were included. Using conventional protocol as the reference, integrated protocol showed β = 34.5 (95%CI, 30.0 to 39.0; P < 0.001) in CNR, β = 1727 (95%CI, 1697 to 1759; P < 0.001) in ERS, β = -39.6 (95%CI, -44.9 to -34.4; P < 0.001) in AI, β = 2.15 (95%CI, 2.04 to 2.27; P < 0.001) in OIQ, β = 1.75 (95%CI, 1.65 to 1.85; P < 0.001) in sharpness, β = 1.15 (95%CI, 1.04 to 1.27; P < 0.001) in noise.

Integrated protocol for CAS using PCD-CT yielded superior qualitative and quantitative performance compared with the conventional protocol.