Abstract 16693: Standalone Quantitative 18 F-NaF Coronary PET Fused With Prior Deep-Inspiration Coronary CT Angiography for Improved Patient Workflow

Abstract

Introduction: 18 F-NaF PET holds promise in distinguishing high-risk plaques in patients with coronary artery disease. The current imaging protocol requires a hybrid single-session acquisition of coronary computed tomography angiography (CTA) and PET. This approach does not allow high-risk patient selection for 18 F-NaF imaging based on prior CTA findings. We aimed to determine whether prior deep inspiration CTA fused with a subsequent PET-only scan allows reliable evaluation of coronary 18 F-NaF uptake. Methods: Twenty-five patients (age 65±6 years, 68% males) underwent clinical CTA (CTA1) on a dual-source CT scanner and subsequently combined 18 F-NaF PET/CTA (CTA2) imaging on a hybrid PET/CT scanner within 16 [9,28] days. We fused CTA1 with 18 F-NaF PET (PET) and compared the visual pattern of activity, maximal standard uptake values (SUVmax) and target to background ratio (TBR) measurements on prior-CTA (PET/CTA1) versus hybrid (PET/CTA2) cardiac motion corrected PET images. Results: On PET/CTA2, 118 coronary plaques were identified. Thirty-six coronary segments from 14 (56%) patients had high 18 F-NaF uptake (TBR>1.25), while 82 segments had lesions with 18 F-NaF TBR ≤1.25. Uptake in all lesions was categorized identically on co-registered PET/CTA1. There was no difference in 18 F-NaF uptake between PET/CTA1 and PET/CTA2 (SUVmax: 1.46±0.59 vs. 1.45±0.57, p=0.53; TBR:1.28±0.55 vs. 1.26±0.53, p=0.41). Repeatability of uptake measurements was excellent with intraclass correlation coefficients of 0.98 (95% CI 0.97 to 0.99, p<0.001) and 0.94 (95% CI 0.92 to 0.96, p<0.001) and limits of agreement of ±0.18 and ±0.19 for SUVmax and TBR respectively. Conclusions: Coronary CTA/PET protocol with CTA first followed by PET-only allows for reliable and reproducible quantification of 18 F-NaF coronary uptake. This approach may facilitate selection of high-risk patients for PET-only imaging based on results from prior CTA, providing a practical workflow for clinical application.