Search

Background Positron emission tomography (PET) using 18 F-sodium fluoride ( 18 F-fluoride) to detect microcalcification may provide insight into disease activity in coronary atherosclerosis. This study aimed to investigate the relationship between 18 F-fluoride uptake and progression of coronary calcification in patients with clinically stable coronary artery disease. Methods Patients with established multivessel coronary atherosclerosis underwent 18 F-fluoride PET-computed tomography angiography and computed tomography calcium scoring, with repeat computed tomography angiography and calcium scoring at one year. Coronary PET uptake was analyzed qualitatively and semiquantitatively in diseased vessels by measuring maximum tissue-to-background ratio. Coronary calcification was quantified by measuring calcium score, mass, and volume. Results In a total of 183 participants (median age 66 years, 80% male), 116 (63%) patients had increased 18 F-fluoride uptake in at least one vessel. Individuals with increased 18 F-fluoride uptake demonstrated more rapid progression of calcification compared with those without uptake (change in calcium score, 97 [39-166] versus 35 [7-93] AU; P <0.0001). Indeed, the calcium score only increased in coronary segments with 18 F-fluoride uptake (from 95 [30-209] to 148 [61-289] AU; P <0.001) and remained unchanged in segments without 18 F-fluoride uptake (from 46 [16-113] to 49 [20-115] AU; P =0.329). Baseline coronary 18 F-fluoride maximum tissue-to-background ratio correlated with 1-year change in calcium score, calcium volume, and calcium mass (Spearman ρ=0.37, 0.38, and 0.46, respectively; P <0.0001 for all). At the segmental level, baseline 18 F-fluoride activity was an independent predictor of calcium score at 12 months ( P <0.001). However, at the patient level, this was not independent of age, sex, and baseline calcium score ( P =0.50). Conclusions Coronary 18 F-fluoride uptake identifies both patients and individual coronary segments with more rapid progression of coronary calcification, providing important insights into disease activity within the coronary circulation. At the individual patient level, total calcium score remains an important marker of disease burden and progression. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02110303.

Background: Coronary 18 F-fluoride positron emission tomography identifies ruptured and high-risk atherosclerotic plaque. The optimal method to identify, to quantify, and to categorize increased coronary 18 F-fluoride uptake and determine its reproducibility has yet to be established. This study aimed to optimize the identification, quantification, categorization, and scan-rescan reproducibility of increased 18 F-fluoride activity in coronary atherosclerotic plaque., Methods: In a prospective observational study, patients with multi-vessel coronary artery disease underwent serial 18 F-fluoride positron emission tomography. Coronary 18 F-fluoride activity was visually assessed, quantified, and categorized with reference to maximal tissue to background ratios. Levels of agreement for both visual and quantitative methods were determined between scans and observers., Results: Thirty patients (90% male, 20 patients with stable coronary artery disease, and 10 with recent type 1 myocardial infarction) underwent paired serial positron emission tomography-coronary computed tomography angiography imaging within an interval of 12±5 days. A mean of 3.7±1.8 18 F-fluoride positive plaques per patient was identified after recent acute coronary syndrome, compared with 2.4±2.3 positive plaques per patient in stable coronary artery disease. The bias in agreement in maximum tissue to background ratio measurements in visually positive plaques was low between observers (mean difference, -0.01; 95% limits of agreement, -0.32 to 0.30) or between scans (mean difference, 0.06; 95% limits of agreement, -0.49 to 0.61). Good agreement in the categorization of focal 18 F-fluoride uptake was achieved using visual assessment alone (κ=0.66) and further improved at higher maximum tissue to background ratio values., Conclusions: Coronary 18 F-fluoride activity is a precise and reproducible metric in the coronary vasculature. The analytical performance of 18 F-fluoride is sufficient to assess the prognostic utility of this radiotracer as a noninvasive imaging biomarker of plaque vulnerability., Clinical Trial Registration: URL: http://www.clinicaltrials.gov. Unique identifiers: NCT02110303 and NCT02278211.