18 F-FAPI Outperforms 18 F-FDG PET/CT in Detecting Focal Inflammation as a Cause of Refractory In-Stent Restenosis :...

Area of Science:

• Cardiovascular Imaging
• Nuclear Medicine
• Radiochemistry

Background:

• Inflammation-associated coronary artery disease (I-CAD) is an underdiagnosed cause of refractory in-stent restenosis (ISR).
• Conventional imaging lacks sensitivity for detecting focal inflammatory activity in ISR.
• Fibroblast activation plays a role in peri-stent remodeling.

Purpose of the Study:

• To evaluate the utility of dual-tracer PET/CT imaging in a patient with recurrent ISR.
• To assess fibroblast activity and inflammation in the peri-stent region.
• To guide therapeutic management based on imaging findings.

Main Methods:

• A 74-year-old woman with recurrent ISR underwent dual-tracer ¹⁸F-FAPI and ¹⁸F-FDG PET/CT.
• PET/CT focused on the left anterior descending artery (LAD) stent segment.
• Radiotracer uptake patterns were analyzed to assess inflammatory activity and fibroblast remodeling.

Main Results:

• Dual-tracer PET/CT revealed increased radiotracer uptake in the LAD stent segment.
• ¹⁸F-FAPI uptake was more intense than ¹⁸F-FDG uptake, indicating fibroblast-related activity.
• Findings suggested an active inflammation-associated mechanism contributing to ISR.

Conclusions:

• Dual-tracer ¹⁸F-FAPI and ¹⁸F-FDG PET/CT can detect inflammation and fibroblast remodeling in recurrent ISR.
• This imaging approach aids in identifying I-CAD mechanisms.
• Findings supported anti-inflammatory therapy over repeat revascularization.