Photon counting CT improves coronary stent imaging and fat attenuation index assessment across reconstruction modes

To investigate the effect of photon counting CT (PCCT) ultra-high resolution (UHR) mode on coronary stent visualization and fat attenuation index (FAI) assessment in individuals with percutaneous coronary intervention (PCI).

Patients who underwent PCI with stent placement and following coronary CT angiography (CCTA) by using a PCCT system were enrolled during January to August 2024. Simulated energy integrating detector CT (EID-CT) images (0.8 mm) were reconstructed with kernel Bv48, while UHR images (0.2 mm) were reconstructed using kernel Bv60 and Bv72. Objective and subjective image quality, stent-specific FAI and peri-stent FAI was evaluated.

A total of 41 patients with 51 isolated stents (69.76 ± 8.75 years; 34 men) were included. Compared to simulated EID-CT, 0.2 mm Bv72 images showed larger in-stent diameters and reduced blooming artifacts (all p < 0.001). Subjective image quality scores for 0.2 mm UHR images were superior to those for simulated EID-CT (all p < 0.01). The stent-specific FAI and peri-stent FAI of 51 isolated stents was lower in the 0.2 mm UHR images than in simulated EID-CT (all p < 0.05). The reconstruction mode of 0.2 mm Bv72 showed the ability of stent-specific FAI and peri-stent FAI to distinguish stents with in-stent restenosis (ISR) < 50 % in diameter from stents without ISR, with cut-off value of -98HU and -99.5HU, respectively.

PCCT UHR mode improved the image quality of coronary stents, reduced the FAI values and provided cut-off values based on stent-specific FAI and peri-stent FAI.