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

Abstract

Sodium 18 F-fluoride ( 18 F-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 18 F-NaF uptake. This study investigated whether blood activity, renal function, injected dose, circulating time, and PET/CT system affect quantification of arterial 18 F-NaF uptake. Methods: Eighty-nine healthy subjects were prospectively examined by 18 F-NaF PET/CT imaging. Arterial 18 F-NaF uptake was quantified at the level of the ascending aorta, aortic arch, descending thoracic aorta, and coronary arteries by calculating the maximum 18 F-NaF activity (NaFmax), the maximum/mean target-to-background ratio (TBRmax/mean), and the maximum blood-subtracted 18 F-NaF activity (bsNaFmax). Multivariable linear regression assessed the effect of personal characteristics and technical factors on quantification of arterial 18 F-NaF uptake. Results: NaFmax and TBRmax/mean were dependent on blood activity (β 5 0.34 to 0.44, P , 0.001, and β 5 −0.68 to −0.58, P , 0.001, respectively) and PET/CT system (β 5 −0.80 to −0.53, P , 0.001, and β 5 −0.80 to −0.23, P , 0.031, respectively). bsNaFmax depended on PET/CT system (β 5 −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 18 F-NaF uptake, whereas renal function and circulating time did not. Conclusion: The prospective evaluation of 89 healthy subjects demonstrated that quantification of arterial 18 F-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 18 F-NaF uptake.

Thoracic aorta calcification but not inflammation is associated with increased cardiovascular disease risk: results of the CAMONA study

“…The image analyst was masked to the subject’s demographics and to the image specifications. Arterial 18 F-FDG and Na 18 F uptake were quantified according to previously published methods [13–15]. In summary, uptake of 18 F-FDG in the thoracic aorta was determined by manually placing an oval region of interest (ROI) around the outer perimeter of the artery on every slice of the axially oriented PET/CT images.…”

“…First, FDG MAX and NaF MAX were adjusted for blood activity, injected dose and PET/CT technology by multivariable linear regression, because previous studies had indicated that these parameters significantly affect the quantification of arterial 18 F-FDG and Na 18 F uptake [15, 16]. Second, subject demographics are summarized by descriptive statistics and compared between healthy volunteers and patients using the unpaired Student’s t test, the Mann-Whitney U test, or Fisher’s exact test.…”

“…All statistical analyses were repeated replacing FDG MAX and NaF MAX with the ratios of the maximum tracer activity in the aortic wall to the mean activity in the blood pool (target-to-background ratios, TBR) for 18 F-FDG and Na 18 F (FDG-TBR MAX/MEAN and NaF-TBR MAX/MEAN , respectively). TBR is commonly used to express aortic FDG and NaF uptake, but its use has been criticized [15, 16]. The results of these analyses are reported in Supplementary Fig.…”

Increased arterial inflammation in individuals with stage 3 chronic kidney disease

“…Measurement of background FDG uptake (venous and muscle) was performed by placing regions of interest (ROI) and the average mean SUV was calculated. The background-corrected SUV was calculated as arterial SUV max minus the mean venous SUV (blood-subtracted SUV maximum: bsSUVmax) [19]. …”

What can be and what cannot be accomplished with PET to detect and characterize atherosclerotic plaques

“…38 For example, we have employed this methodology in detecting uptakes of FDG and NaF in atherosclerotic plaques with high sensitivity. 21,[44][45][46][47][48][49] Specifically, we have validated measurements of global coronary artery calcification with NaF-PET in animals and human studies.…”