Feasibility of On-Site CT-FFR Analysis in Ruling Out In-Stent Restenosis on Cardiac PCCT

Area of Science:

• Cardiovascular Imaging
• Medical Devices
• Diagnostic Technology

Background:

• Coronary computed tomography angiography (CCTA) is crucial for evaluating coronary stents.
• Assessing in-stent restenosis (ISR) remains a significant challenge in cardiovascular imaging.
• Photon-Counting Detector CT (PCCT) offers potential improvements for stent assessment and CT-derived fractional flow reserve (CT-FFR) analysis.

Purpose of the Study:

• To evaluate the feasibility and diagnostic performance of on-site CT-FFR analysis using PCCT for detecting ISR in coronary stents.
• To compare the diagnostic accuracy of post-stent CT-FFR and Delta CT-FFR in identifying ISR.
• To assess the 6-month rate of major adverse cardiovascular events (MACE) following CCTA.

Main Methods:

• Patients with prior coronary stent implantation underwent CCTA with PCCT and subsequent invasive catheter angiography (ICA).
• Stent characteristics were recorded, and CT-FFR measurements were taken pre- and post-stent.
• Delta CT-FFR was calculated, and diagnostic performance metrics for ISR detection were determined.

Main Results:

• Post-stent CT-FFR and Delta CT-FFR demonstrated 100% sensitivity and negative predictive value (NPV) for excluding ISR.
• Post-stent CT-FFR showed superior specificity (76.5%) and overall diagnostic accuracy (78.9%) compared to Delta CT-FFR.
• Two cases of ISR were confirmed by ICA among three patients who underwent the procedure.

Conclusions:

• On-site CT-FFR analysis using PCCT is feasible for excluding ISR in coronary stents with high diagnostic accuracy.
• Post-stent CT-FFR is a valuable parameter for ruling out ISR, offering high sensitivity and NPV.
• These findings support the expanded use of CT-FFR for non-invasive ISR assessment, personalized risk stratification, and therapy planning.