Brief Report
A longitudinal pilot study to assess temporal changes in coronary arterial 18F-sodium fluoride uptake

https://doi.org/10.1007/s12350-022-02975-wGet rights and content

Abstract

Purpose

How coronary arterial 18F-sodium fluoride (18F-NaF) uptake on positron emission tomography changes over the long term and what clinical factors impact the changes remain unclear. We sought to investigate the topics in this study.

Methods

We retrospectively studied 15 patients with ≥1 coronary atherosclerotic lesion/s detected on cardiac computed tomography who underwent baseline and follow-up (interval of >3 years) 18F-NaF positron emission tomography/computed tomography scans. Focal 18F-NaF uptake in each lesion was quantified using maximum tissue-to-background ratio (TBRmax). The temporal change in TBRmax was assessed using a ratio of follow-up to baseline TBRmax (R-TBRmax).

Results

A total of 51 lesions were analyzed. Mean R-TBRmax was 0.96 ± 0.21. CT-based lesion features (location, obstructive stenosis, plaque types, features of high-risk plaque) did not correlate with an increase in R-TBRmax. In multivariate analysis, baseline TBRmax significantly correlated with higher follow-up TBRmax (β = 0.57, P < 0.0001), and the presence of diabetes mellitus significantly correlated with both higher follow-up TBRmax (β = 0.34, P = 0.001) and elevated R-TBRmax (β = 0.40, P = 0.003).

Conclusion

Higher coronary arterial 18F-NaF uptake is likely to remain continuously high. Diabetes mellitus affects the long-term increase in coronary arterial 18F-NaF uptake.

Introduction

18F-sodium fluoride (18F-NaF) positron emission tomography (PET) reportedly identifies high-risk atherosclerotic plaques with active calcification.1, 2, 3 Intense 18F-NaF uptake was shown in recently-ruptured coronary plaques in patients with acute myocardial infarction.4 In addition, we and others have demonstrated that 18F-NaF PET is a determinant of disease activity in coronary arteries and has the potential to predict future coronary events in patients with established coronary artery disease.5,6 Consequently, 18F-NaF PET has attracted clinical interest as a novel option to stratify the patient-based and lesion-based risks of coronary artery disease.

In lesion-based studies, coronary plaques with high-risk characteristics on intravascular imaging have higher 18F-NaF uptake compared with plaques without such characteristics.7 We previously found a relationship between coronary plaque characteristics on coronary computed tomography angiography (CCTA) and coronary arterial 18F-NaF uptake.8 However, how coronary arterial 18F-NaF uptake changes over the long term and what clinical factors impact the temporal changes remain unclear. This information may provide important insights into the management of coronary artery disease, because increased 18F-NaF uptake in coronary plaques reportedly has the prognostic value.5,6 In this study, we evaluated the temporal changes in coronary arterial 18F-NaF uptake in a longitudinal follow-up cohort, and sought clinical factors related to changes in 18F-NaF uptake.

Section snippets

Materials and Methods

We retrospectively studied 15 patients who underwent baseline and follow-up 18F-NaF PET/CT scans between June 2014 and July 2021. All patients underwent cardiac computed tomography (CT) at baseline and had at least one coronary atherosclerotic lesion detected on CCTA in segments >2-mm in diameter according to the Society of Cardiovascular Computed Tomography’s 18-segment model.9 All patients underwent 18F-NaF PET/CT within 1 month of cardiac CT imaging as the baseline scan, followed by the

Results

In the 15 study patients, CCTA visualized a total of 55 coronary atherosclerotic lesions, 51 of which could be identified and analyzed on the baseline and follow-up PET/CT images (mean, 3.4 ± 1.0 per patient; range, 2-5 lesions per patient). The reasons for difficulty in identifying the lesions on the PET/CT images included motion artifact and the lower spatial resolution of the fused PET/CT images. Table 1 shows the baseline and follow-up characteristics of the patients and characteristics of

Discussion

In this pilot study, we investigated how coronary arterial 18F-NaF uptake changed at intervals of more than 3 years. Additionally, we sought patient and lesion factors related to the temporal changes in coronary arterial 18F-NaF uptake. We found the following: (1) Higher 18F-NaF uptake in coronary atherosclerosis at baseline was likely to remain continuously high, while it did not affect the increase in the 18F-NaF uptake; (2) CT-based features of coronary atherosclerosis did not correlate with

New Knowledge Gained

Higher coronary arterial 18F-NaF uptake is likely to remain continuously high. Diabetes mellitus may be an important factor promoting coronary arterial 18F-NaF uptake over the long term.

Disclosures

Toshiro Kitagawa, Ko Sasaki, Yuto Fujii, Fuminari Tatsugami, Kazuo Awai, Yutaka Hirokawa, and Yukiko Nakano report no relevant disclosures.

Funding

This study was supported by the Mochida Memorial Foundation for Medical and Pharmaceutical Research, and a JSPS KAKENHI Grant-in-Aid for Scientific Research (Grant Number 21K08127).

References (12)

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