Quantifying microcalcification activity in the thoracic aorta.

Area of Science:

• Cardiovascular imaging
• Nuclear medicine
• Radiochemistry

Background:

• Standard positron emission tomography (PET) methods for quantifying aortic uptake are time-consuming.
• Existing methods may not fully capture overall aortic vessel activity.
• ¹⁸F-sodium fluoride (18F-NaF) is a radiotracer used to assess calcification.

Purpose of the Study:

• To introduce and evaluate a novel method, aortic microcalcification activity (AMA), for quantifying ¹⁸F-NaF uptake in the thoracic aorta.
• To assess the repeatability and reproducibility of AMA.
• To compare AMA with established cardiovascular risk scores.

Main Methods:

• Twenty patients underwent serial hybrid ¹⁸F-NaF PET/CT scans.
• Aortic microcalcification activity (AMA), TBRmax, and TBRmean were calculated by two operators.
• Intra-observer, inter-observer, and scan-rescan reproducibility were assessed and compared to cardiovascular risk scores.

Main Results:

• AMA demonstrated excellent intra-observer (ICC 0.98) and inter-observer (ICC 0.97) repeatability.
• Scan-rescan reproducibility for AMA was very good (ICC 0.86).
• AMA analysis was significantly faster (3.4 min vs. 15.1 min, P<0.0001) and correlated with Framingham risk scores.

Conclusions:

• Aortic microcalcification activity (AMA) is a simple, rapid, and reproducible method for quantifying global ¹⁸F-NaF uptake in the thoracic aorta.
• AMA provides a reliable assessment of aortic activity across the ascending aorta and aortic arch.
• The method's correlation with cardiovascular risk scores highlights its clinical relevance.