Impact of Personal Characteristics and Technical Factors on Quantification of Sodium 18F-Fluoride Uptake in Human Arteries: Prospective Evaluation of Healthy Subjects

Sodium F-18-fluoride (F-18-NaF) PET/CT imaging is a promising imaging technique for the assessment of atherosclerosis but is hampered by a lack of validated quantification protocols. Both personal characteristics and technical factors can affect quantification of arterial F-18-NaF uptake. This study investigated whether blood activity, renal function, injected dose, circulating time, and PET/CT system affect quantification of arterial F-18-NaF uptake. Methods: Eighty-nine healthy subjects were prospectively examined by F-18-NaF PET/CT imaging. Arterial F-18-NaF uptake was quantified at the level of the ascending aorta, aortic arch, descending thoracic aorta, and coronary arteries by calculating the maximum F-18-NaF activity (NaFmax), the maximum/mean target-to-background ratio (TBRmax/mean), and the maximum blood-subtracted F-18-NaF activity (bsNaFmax). Multivariable linear regression assessed the effect of personal characteristics and technical factors on quantification of arterial F-18-NaF uptake. Results: NaFmax and TBRmax/mean were dependent on blood activity (beta = 0.34 to 0.44, P <0.001, and beta = -0.68 to -0.58, P <0.001, respectively) and PET/CT system (beta = -0.80 to -0.53, P <0.001, and beta = -0.80 to -0.23, P <0.031, respectively). bsNaFmax depended on PET/CT system (beta = -0.91 to -0.57, P <0.001) but not blood activity. This finding was observed at the level of the ascending aorta, aortic arch, descending thoracic aorta, and the coronary arteries. In addition to blood activity and PET/CT system, injected dose affected quantification of arterial F-18-NaF uptake, whereas renal function and circulating time did not. Conclusion: The prospective evaluation of 89 healthy subjects demonstrated that quantification of arterial F-18-NaF uptake is affected by blood activity, injected dose, and PET/CT system. Therefore, blood activity, injected dose, and PET/CT system should be considered to generate accurate estimates of arterial F-18-NaF uptake.