title: PET Molecular Imaging of Hypoxia in Ischemic Stroke: An Update.
abstract: Hypoxia, a condition of insufficient oxygen availability to support metabolism, occurs when the vascular supply is interrupted, as in stroke. The identification of the hypoxic and viable tissue in stroke as compared with irreversible lesions (necrosis) has relevant implications for the treatment of ischemic stroke. Traditionally, imaging by positron emission tomography (PET), using 15O-based radiotracers, allowed the measurement of perfusion and oxygen extraction in stroke, providing important insights in its pathophysiology. However, these multitracer evaluations are of limited applicability in clinical settings. More recently, specific tracers have been developed, which accumulate with an inverse relationship to oxygen concentration and thus allow visualizing the hypoxic tissue non invasively. These belong to two main groups: nitroimidazoles, and among these the 18F-Fluoroimidazole (18F-FMISO) is the most widely used, and the copper-based tracers, represented mainly by Cu-ATSM. While these tracers have been at first developed and tested in order to image hypoxia in tumors, they have also shown promising results in stroke models and preliminary clinical studies in patients with cardiovascular disorders, allowing the detection of hypoxic tissue and the prediction of the extent of subsequent ischemia and clinical outcome. These tracers have therefore the potential to select an appropriate subgroup of patients who could benefit from a hypoxia-directed treatment and provide prognosis relevant imaging. The molecular imaging of hypoxia made important progress over the last decade and has a potential for integration into the diagnostic and therapeutic workup of patients with ischemic stroke.
authors.forename: Aylin
authors.initials: A
authors.lastname: Baskin
authors.forename: Franz
authors.initials: F
authors.lastname: Buchegger
authors.forename: Yann
authors.initials: Y
authors.lastname: Seimbille
authors.forename: Osman
authors.initials: O
authors.lastname: Ratib
authors.affiliation: Nuclear Medicine Division, Department of Medical Imaging, Geneva University Hospital, Rue Gabrielle- Perret-Gentil 4, 1211 Geneve 14, Switzerland. valentina.garibotto@hcuge.ch.
authors.forename: Valentina
authors.initials: V
authors.lastname: Garibotto
mesh_terms: D000818:Animals; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging* / Q000378:metabolism; D002545:Brain Ischemia / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D002560:Cerebrovascular Circulation; D004195:Disease Models, Animal; D006801:Humans; D002534:Hypoxia, Brain / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy; D010100:Oxygen / Q000378:metabolism; D018579:Patient Selection; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D011379:Prognosis; D019275:Radiopharmaceuticals; D012307:Risk Factors; D020521:Stroke / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy
chemical_list: D019275:Radiopharmaceuticals; D010100:Oxygen