Feasibility of Coronary 18F-Sodium Fluoride Positron-Emission Tomography Assessment With the Utilization of Previously Acquired Computed Tomography Angiography

BACKGROUND: We assessed the feasibility of utilizing previously acquired computed tomography angiography (CTA) with subsequent positron-emission tomography (PET)-only scan for the quantitative evaluation of F-18-NaF PET coronary uptake. METHODS AND RESULTS: Forty-five patients (age 67.1 +/- 6.9 years; 76% males) underwent CTA (CTA1) and combined 18F-NaF PET/CTA (CTA2) imaging within 14 [10, 21] days. We fused CTA1 from visit 1 with 18F-NaF PET (PET) from visit 2 and compared visual pattern of activity, maximal standard uptake (SUVmax) values, and target to background ratio (TBR) measurements on (PET/CTA1) fused versus hybrid (PET/CTA2). On PET/CTA2, 226 coronary plaques were identified. Fifty-eight coronary segments from 28 (62%) patients had high F-18-NaF uptake (TBR > 1.25), whereas 168 segments had lesions with F-18-NaF TBR = 1.25. Uptake in all lesions was categorized identically on coregistered PET/CTA1. There was no significant difference in F-18-NaF uptake values between PET/ CTA1 and PET/CTA2 (SUVmax, 1.16 +/- 0.40 versus 1.15 +/- 0.39; P= 0.53; TBR, 1.10 +/- 0.45 versus 1.09 +/- 0.46; P= 0.55). The intraclass correlation coefficient for SUVmax and TBR was 0.987 (95% CI, 0.983-0.991) and 0.986 (95% CI, 0.981-0.992). There was no fixed or proportional bias between PET/CTA1 and PET/CTA2 for SUVmax and TBR. Cardiac motion correction of PET scans improved reproducibility with tighter 95% limits of agreement (+/- 0.14 for SUVmax and +/- 0.15 for TBR versus +/- 0.20 and +/- 0.20 on diastolic imaging; P< 0.001). CONCLUSIONS: Coronary CTA/PET protocol with CTA first followed by PET-only allows for reliable and reproducible quantification of F-18-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.