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Dual-Tracer Positron-Emission Tomography for Identification of Culprit Carotid Plaques and Pathophysiology In Vivo.

Accepted version
Peer-reviewed

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Type

Article

Change log

Authors

Evans, Nicholas R 
Tarkin, Jason M 
Chowdhury, Mohammed M 
Le, Elizabeth PV 
Coughlin, Patrick A 

Abstract

BACKGROUND: Inflammation and microcalcification are interrelated processes contributing to atherosclerotic plaque vulnerability. Positron-emission tomography can quantify these processes in vivo. This study investigates (1) 18F-fluorodeoxyglucose (FDG) and 18F-sodium fluoride (NaF) uptake in culprit versus nonculprit carotid atheroma, (2) spatial distributions of uptake, and (3) how macrocalcification affects this relationship. METHODS: Individuals with acute ischemic stroke with ipsilateral carotid stenosis of ≥50% underwent FDG-positron-emission tomography and NaF-positron-emission tomography. Tracer uptake was quantified using maximum tissue-to-background ratios (TBRmax) and macrocalcification quantified using Agatston scoring. RESULTS: In 26 individuals, median most diseased segment TBRmax (interquartile range) was higher in culprit than in nonculprit atheroma for both FDG (2.08 [0.52] versus 1.89 [0.40]; P<0.001) and NaF (2.68 [0.63] versus 2.39 [1.02]; P<0.001). However, whole vessel TBRmax was higher in culprit arteries for FDG (1.92 [0.41] versus 1.71 [0.31]; P<0.001) but not NaF (1.85 [0.28] versus 1.79 [0.60]; P=0.10). NaF uptake was concentrated at carotid bifurcations, while FDG was distributed evenly throughout arteries. Correlations between FDG and NaF TBRmax differed between bifurcations with low macrocalcification (rs=0.38; P<0.001) versus high macrocalcification (rs=0.59; P<0.001). CONCLUSIONS: This is the first study to demonstrate increased uptake of both FDG and NaF in culprit carotid plaques, with discrete distributions of pathophysiology influencing vulnerability in vivo. These findings have implications for our understanding of the natural history of the disease and for the clinical assessment and management of carotid atherosclerosis.

Description

Keywords

carotid arteries, carotid stenosis, inflammation, positron emission tomography, sodium fluoride, Aged, Blood Flow Velocity, Brain Ischemia, Carotid Arteries, Carotid Stenosis, Female, Follow-Up Studies, Humans, Male, Plaque, Atherosclerotic, Positron Emission Tomography Computed Tomography, Prospective Studies

Journal Title

Circ Cardiovasc Imaging

Conference Name

Journal ISSN

1941-9651
1942-0080

Volume Title

13

Publisher

Ovid Technologies (Wolters Kluwer Health)
Sponsorship
The Dunhill Medical Trust (None)
Wellcome Trust (104492/Z/14/Z)
Wellcome Trust (211100/Z/18/Z)
British Heart Foundation (None)
Academy of Medical Sciences (unknown)
British Heart Foundation (None)
Evelyn Trust (unknown)
Engineering and Physical Sciences Research Council (EP/N014588/1)
Medical Research Council (MR/N028015/1)
British Heart Foundation (FS/16/29/31957)
Cambridge University Hospitals NHS Foundation Trust (CUH) (146281)
Cambridge University Hospitals NHS Foundation Trust (CUH) (unknown)
NRE is supported by a Research Training Fellowship from The Dunhill Medical Trust [RTF44/0114]. JMT is supported by the Wellcome Trust (211100/Z/18/Z, 104492/Z/14/7) and the National Institute for Health Research (NIHR). MMC is supported by Royal College of Surgeons of England and British Heart Foundation (BHF) fellowships (FS/16/29/31957). JHFR is supported by the NIHR Cambridge Biomedical Centre, BHF, Wellcome Trust, and Higher Education Funding Council for England. EAW is supported by the NIHR Cambridge Biomedical Centre.