22 Jan 21. Featured Paper

Quantifying microcalcification activity in the thoracic aorta.

Link to paper on Journal of Nuclear Cardiology

Authors

Alexander J. Fletcher MBChB, Maria Lembo MD, Jacek Kwiecinski MD, Maaz B. J. Syed MBChB, Jennifer Nash MBChB, Evangelos Tzolos MD, Rong Bing MBBS, Sebastien Cadet MS, Gillian MacNaught PhD, Edwin J. R. van Beek MD, PhD, Alistair J. Moss PhD, Mhairi K. Doris MBChB, Niki L. Walker MD, PhD, Damini Dey PhD, Philip D. Adamson MD, PhD, David E. Newby MD, PhD, Piotr J. Slomka MD, PhD & Marc R. Dweck MD, PhD

Abstract

Background: Standard methods for quantifying positron emission tomography (PET) uptake in the aorta are time consuming & may not reflect overall vessel activity.

We describe aortic microcalcification activity (AMA), a novel method for quantifying ¹⁸F-sodium fluoride (18F-NaF) uptake in the thoracic aorta.

Methods: Twenty patients underwent two hybrid ¹⁸F-NaF PET & computed tomography (CT) scans of the thoracic aorta less than three weeks apart.

AMA, as well as maximum (TBRmax) & mean (TBRmean) tissue to background ratios, were calculated by two trained operators.

Intra-observer repeatability, inter-observer repeatability & scan-rescan reproducibility were assessed.

Each ¹⁸F-NaF quantification method was compared to validated cardiovascular risk scores.

Results: Aortic microcalcification activity demonstrated excellent intra-observer (intraclass correlation coefficient 0.98) & inter-observer (intraclass correlation coefficient 0.97) repeatability with very good scan-rescan reproducibility (intraclass correlation coefficient 0.86) which were similar to previously described TBRmean & TBRmax methods.

AMA analysis was much quicker to perform than standard TBR assessment (3.4min versus 15.1min, P<0.0001).

AMA was correlated with Framingham stroke risk scores & Framingham risk score for hard cononary heart disease.

Conclusions: AMA is a simple, rapid & reproducible method of quantifying global ¹⁸F-NaF uptake across the ascending aorta & aortic arch that correlates with cardiovascular risk scores.

Keywords

• Image analysis
• Modalities
• Molecular imaging agents
• Others
• PET
• Technical
• Tests
• Tracers