A new PET radiotracer called gallium-68-pentixafor can noninvasively and rapidly detect life-threatening atheroscloerotic plaques, according to a study recently published in The Journal of Nuclear Medicine.

Atherosclerosis is the leading cause of heart attack and stroke. Over the course of 10 years, lipids, inflammatory cells and connective tissue accumulate within the inner layer of the arterial walls and the vascular walls, and atheroscloerotic plaque thickens.

These plaques can cause no symptoms for years, but eventually an inflammatory reaction can develop and the plaques will rupture and form a clot. If the clot completely blocks an artery, oxygen can't reach the downstream tissue, which can result in a heart attack or stroke.
Historically, it's been a challenge to spot patients with these atheroscloerotic plaques before a heart attack or stroke occurs. There currently aren't any clinical noninvasive imaging techniques to detect inflammation.

FDG-PET is used but it's taken up by mostly cardiac and brain cells instead of inflammatory cells. The strong signals from the heart and brain limit the analysis of radiotracer uptake in the atheroscloerotic plaques.

Patients also have to fast for at least six hours before they receive the FDG injection to prevent blood sugar and muscular uptake interference, which can affect image quality.

For the study, the researchers tested Ga-68-pentixafor on seven rabbits with atheroscloerotic plaques, and five controls. They underwent PET/MR exams after being injected with the radiotracer.

The images revealed inflammation in plaques in the abdominal aorta and right carotid artery. This confirms that Ga-68-pentixafor binds more specifically to inflammatory cells than FDG.

The research team also tested Ga-68-pentixafor on a small group of human patients and it detected atheroscloerotic plaques in their carotid arteries as well.

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