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Shining dead bone-cause for cautious interpretation of [18F]NaF PET scans.

ABSTRACT: Background and purpose - [18F]Fluoride ([18F]NaF) PET scan is frequently used for estimation of bone healing rate and extent in cases of bone allografting and fracture healing. Some authors claim that [18F]NaF uptake is a measure of osteoblastic activity, calcium metabolism, or bone turnover. Based on the known affinity of fluoride to hydroxyapatite, we challenged this view. Methods - 10 male rats received crushed, frozen allogeneic cortical bone fragments in a pouch in the abdominal wall on the right side, and hydroxyapatite granules on left side. [18F]NaF was injected intravenously after 7 days. 60?minutes later, the rats were killed and [18F]NaF uptake was visualized in a PET/CT scanner. Specimens were retrieved for micro CT and histology. Results - MicroCT and histology showed no signs of new bone at the implant sites. Still, the implants showed a very high [18F]NaF uptake, on a par with the most actively growing and remodeling sites around the knee joint. Interpretation - [18F]NaF binds with high affinity to dead bone and calcium phosphate materials. Hence, an [18F]NaF PET/CT scan does not allow for sound conclusions about new bone ingrowth into bone allograft, healing activity in long bone shaft fractures with necrotic fragments, or remodeling around calcium phosphate coated prostheses.

SUBMITTER: Bernhardsson M

PROVIDER: S-EPMC5810820 | biostudies-other | 2018 Feb

REPOSITORIES: biostudies-other

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Shining dead bone-cause for cautious interpretation of [18F]NaF PET scans.

Bernhardsson Magnus M Sandberg Olof O Ressner Marcus M Koziorowski Jacek J Malmquist Jonas J Aspenberg Per P

Acta orthopaedica 20170915 1

Background and purpose - [18F]Fluoride ([18F]NaF) PET scan is frequently used for estimation of bone healing rate and extent in cases of bone allografting and fracture healing. Some authors claim that [18F]NaF uptake is a measure of osteoblastic activity, calcium metabolism, or bone turnover. Based on the known affinity of fluoride to hydroxyapatite, we challenged this view. Methods - 10 male rats received crushed, frozen allogeneic cortical bone fragments in a p ...[more]

PMID: 28914114

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Project description:Aortic valve calcification is a slow and progressive pathological process that can manifest in various degrees from mild thickening of the valve known as aortic sclerosis to severe calcification that hinders the leaflet motion, known as aortic stenosis. The evolving concept of aortic calcification is thought to result from infiltration of macrophages and T-lymphocytes. Moreover, the incidence of aortic valve calcification increases with age, in particular over the age of 50. In this study, we aimed to assess 18F-sodium fluoride (18F-NaF) uptake by the aortic valve on PET/CT scans performed in two age groups; 25-35 and 50-75 years of age. We hypothesized that patients aged 50-75, comprising of both healthy and high risk for cardiovascular disease (CVD), would have higher uptake of 18F-NaF than patients aged 25-35 and further that in the former group those who were at high risk for CVD had also higher 18F-NaF uptake. The 25-35-year group comprised of 6 males and 6 females, mean age 30 ± 3.5 years, while the 50-75-year group included 18 males and 20 females, mean age 61 ± 6.2 years. All underwent PET/CT imaging 90 minutes following the injection of 2.2 MBq of 18F-NaF per kg body weight. Aortic valve analysis was performed on axial sections using standard guided computer software (OsiriX MD software, version 9.0.02). The average aortic valve SUVmean was calculated for each patient. Univariate regression models stratified by age group were employed to determine the association of SUVmean with age. In the 50-75-year group, explanatory multivariable regression modeling was applied using available demographic and baseline information. SUVmean was found to be higher in the 50-75 age group than in the 25-35 age group: 0.91 ± 0.25 and 0.86 ± 0.26, respectively. The association of SUVmean with age was much stronger in individuals aged 50-75 years (r = 0.64, P<0.001) than individuals aged 25-35 years (r = 0.20, P = 0.53). In addition, in the 50-75 age group the association was much stronger in subjects with a high risk of CVD than in individuals without: r = 0.68, P = 0.001 versus r = 0.48, P = 0.042. Furthermore, the SUVmean was found to be higher in the high-risk group aged 50-75 than in the low-risk healthy group aged 50-75: 0.98 ± 0.32 and 0.83 ± 0.13. Aortic valve 18F-NaF uptake was higher in patients belonging to the age group of 50-75 years and correlated positively with age and high risk of CVD. These data provide evidence for a potential role of 18F-NaF PET/CT in identifying calcific changes in the aortic valve and may help direct therapeutic intervention prior to the development of symptomatic valvular disease.

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Dataset Information

Shining dead bone-cause for cautious interpretation of [18F]NaF PET scans.

Publications

Shining dead bone-cause for cautious interpretation of [<sup>18</sup>F]NaF PET scans.

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