Low-tube-potential ultra-high-resolution coronary CTA with photon-counting detector CT for stent evaluation: a comparative feasibility study.

OBJECTIVES

This study aimed to evaluate the feasibility of low-tube-potential ultra-high-resolution (UHR) coronary CT angiography (CCTA) using photon-counting detector CT (PCD-CT) in comparison to low-tube-potential CCTA using energy-integrating detector CT (EID-CT), with a specific focus on the evaluation of coronary stents.

MATERIALS AND METHODS

This retrospective study included 54 patients (88 stents) who underwent CCTA in UHR mode on PCD-CT at low tube potential (PCD-low; 27 patients [45 stents]) or CCTA with EID-CT at low tube potential (EID-low; 27 patients [43 stents]). The EID-low cohort was selected by propensity score matching to the PCD-low cohort. Image quality of in-stent lumen was assessed using a 4-point Likert scale, with a score of 4 indicating "excellent." Quantitative assessment of stents included stent-induced blooming, edge sharpness, stent full width at half maximum (FWHM) and ΔHU which quantifies the increase in CT attenuation within the stent lumen. Radiation dose was evaluated using CT dose index volume (CTDIvol) and dose-length product (DLP).

RESULTS

PCD-low had higher image quality scores than EID-low (scores of 3 and 4, 82.2% vs. 53.5%; p = 0.02). PCD-low showed reduced stent-induced blooming, superior edge sharpness, smaller stent FWHM and smaller ΔHU than EID-low (all, p < 0.01). CTDIvol and DLP in PCD-low (9.3 ± 4.4 mGy and 107.1 ± 50.4 mGy・cm) were comparable to those of EID-low (10.5 ± 5.9 mGy and 118.2 ± 74.9 mGy・cm), respectively. (p = 0.26 and 0.47).

CONCLUSION

CCTA using UHR mode in PCD-CT at low tube potential achieved superior image quality for implanted stent visualization as compared to EID-CT at low tube potential, while maintaining comparable radiation doses.