title: High-risk plaque features can be detected in non-stenotic carotid plaques of patients with ischaemic stroke classified as cryptogenic using combined (18)F-FDG PET/MR imaging.
abstract: OBJECTIVE
  The aim of this study was to investigate in 18 patients with ischaemic stroke classified as cryptogenic and presenting non-stenotic carotid atherosclerotic plaques the morphological and biological aspects of these plaques with magnetic resonance imaging (MRI) and (18)F-fluoro-deoxyglucose positron emission tomography ((18)F-FDG PET) imaging.
  
  
  METHODS
  Carotid arteries were imaged 150 min after injection of (18)F-FDG with a combined PET/MRI system. American Heart Association (AHA) lesion type and plaque composition were determined on consecutive MRI axial sections (n = 460) in both carotid arteries. (18)F-FDG uptake in carotid arteries was quantified using tissue to background ratio (TBR) on corresponding PET sections.
  
  
  RESULTS
  The prevalence of complicated atherosclerotic plaques (AHA lesion type VI) detected with high-resolution MRI was significantly higher in the carotid artery ipsilateral to the ischaemic stroke as compared to the contralateral side (39 vs 0 %; p = 0.001). For all other AHA lesion types, no significant differences were found between ipsilateral and contralateral sides. In addition, atherosclerotic plaques classified as high-risk lesions with MRI (AHA lesion type VI) were associated with higher (18)F-FDG uptake in comparison with other AHA lesions (TBR = 3.43 ± 1.13 vs 2.41 ± 0.84, respectively; p < 0.001). Furthermore, patients presenting at least one complicated lesion (AHA lesion type VI) with MRI showed significantly higher (18)F-FDG uptake in both carotid arteries (ipsilateral and contralateral to the stroke) in comparison with carotid arteries of patients showing no complicated lesion with MRI (mean TBR = 3.18 ± 1.26 and 2.80 ± 0.94 vs 2.19 ± 0.57, respectively; p < 0.05) in favour of a diffuse inflammatory process along both carotid arteries associated with complicated plaques.
  
  
  CONCLUSIONS
  Morphological and biological features of high-risk plaques can be detected with (18)F-FDG PET/MRI in non-stenotic atherosclerotic plaques ipsilateral to the stroke, suggesting a causal role for these plaques in stroke. Combined (18)F-FDG PET/MRI systems might help in the evaluation of patients with ischaemic stroke classified as cryptogenic.
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany. fabien.hyafil@gmail.com.|Department of Nuclear Medicine, Bichat University Hospital, Inserm 1148, DHU FIRE, Assistance Publique - Hôpitaux de Paris, Paris, France. fabien.hyafil@gmail.com.
authors.forename: Fabien
authors.initials: F
authors.lastname: Hyafil
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilians University Hospital Munich, Munich, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schindler
authors.affiliation: Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Dominik
authors.initials: D
authors.lastname: Sepp
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilians University Hospital Munich, Munich, Germany.
authors.forename: Tilman
authors.initials: T
authors.lastname: Obenhuber
authors.affiliation: Institute for Stroke and Dementia Research, Ludwig Maximilians University Hospital Munich, Munich, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Bayer-Karpinska
authors.affiliation: Department of Neuroradiology, Klinikum Rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Boeckh-Behrens
authors.affiliation: Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Höhn
authors.affiliation: Division of Nuclear Medicine, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
authors.forename: Marcus
authors.initials: M
authors.lastname: Hacker
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.|German Centre for Cardiovascular Research (DZHK), Partner Site Munich Heart Alliance, Munich, Germany.
authors.forename: Stephan G
authors.initials: SG
authors.lastname: Nekolla
authors.affiliation: Department of Nuclear Medicine, Ludwig Maximilians University Hospital Munich, Munich, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Rominger
authors.affiliation: Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.|Munich Cluster of Systems Neurology (SyNergy), Munich, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Dichgans
authors.affiliation: Department of Nuclear Medicine, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schwaiger
authors.affiliation: Institute for Clinical Radiology, Ludwig Maximilians University Hospital Munich, Munich, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Saam
authors.affiliation: Department of Neurology, Klinikum rechts der Isar, Technische Universität München, Munich, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Poppert
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology; D002340:Carotid Artery Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D058226:Plaque, Atherosclerotic / Q000150:complications / Q000000981:diagnostic imaging* / Q000473:pathology; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D020521:Stroke / Q000000981:diagnostic imaging* / Q000209:etiology / Q000473:pathology
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: 18F-FDG; Atherosclerosis; Carotid arteries; MRI; PET; Stroke; Vulnerable plaque