Dataset Information

Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments.

ABSTRACT: Positron emission tomography (PET) is widely used in clinical and animal studies, along with the development of diverse tracers. The biochemical characteristics of PET tracers may help uncover the pathophysiological consequences of cardiac arrest (CA) and ischemic stroke, which include cerebral ischemia and reperfusion, depletion of oxygen and glucose, and neuroinflammation. PubMed was searched for studies of the application of PET for "cardiac arrest," "ischemic stroke," and "targeted temperature management." Available studies were included and classified according to the biochemical properties involved and metabolic processes of PET tracers, and were summarized. The mechanisms of ischemic brain injuries were investigated by PET with various tracers to elucidate the pathological process from the initial decrease of cerebral blood flow (CBF) to the subsequent abnormalities in energy and oxygen metabolism, to the monitoring of inflammation. In general, the trends of cerebral blood flow and oxygen metabolism after ischemic attack are not unidirectional but closely related to the time point of injury and recovery. Glucose metabolism after injury showed significant differences in different brain regions whereas global cerebral metabolic rate of glucose (CMRglc) declined. PET monitoring of neuroinflammation shows comparable efficacy to immunostaining. The technology of PET targeting in brain metabolism and the development of tracers provide new tools to track and evaluate the brain's pathological changes after ischemic brain injury. Despite no existing evidence for an available PET-based prediction method, discoveries of new tracers are expected to provide more possibilities for the whole field.

SUBMITTER: Wang Z

PROVIDER: S-EPMC7347441 | biostudies-literature | 2020 Aug

REPOSITORIES: biostudies-literature

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Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments.

Wang Zhuoran Z Mascarenhas Conrad C Jia Xiaofeng X

Translational stroke research 20200114 4

Positron emission tomography (PET) is widely used in clinical and animal studies, along with the development of diverse tracers. The biochemical characteristics of PET tracers may help uncover the pathophysiological consequences of cardiac arrest (CA) and ischemic stroke, which include cerebral ischemia and reperfusion, depletion of oxygen and glucose, and neuroinflammation. PubMed was searched for studies of the application of PET for "cardiac arrest," "ischemic stroke," and "targeted temperatu ...[more]

PMID: 31939060

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Project description:Background and Purpose- The clinical utility of positron emission tomography (PET) imaging in evaluating carotid artery plaque vulnerability remains unclear. Two tracers of recent interest for carotid plaque imaging are 18F-fluorodeoxyglucose (18F-FDG) and 18F-sodium fluoride (18F-NaF). We performed a systematic review and meta-analysis evaluating the association between carotid artery 18F-FDG or 18F-NaF uptake and recent or future cerebral ischemic events. Methods- A systematic review of Ovid MEDLINE, Ovid EMBASE, and the Cochrane library was conducted from inception to December 2017 for articles evaluating PET tracer uptake in recently symptomatic versus asymptomatic carotid arteries, and articles evaluating carotid uptake in relation to future ischemic events. Cerebral ischemic events were defined as ipsilateral strokes, transient ischemic attacks, or amaurosis fugax. We quantitatively pooled studies by a random-effects model when 3 or more studies were amenable for analysis. We assessed the standardized mean difference between tracer uptake in the symptomatic versus asymptomatic carotid artery using Cohen's d metric. Results- After screening 4144 unique articles, 13 prospective cohort studies assessing carotid artery 18F-FDG uptake in patients with recent cerebral ischemia were eligible for review. Eleven cohorts of 290 subjects scanned with 18F-FDG were eligible for meta-analysis. We found that carotid arteries ipsilateral to recent ischemic events had significantly higher 18F-FDG uptake than asymptomatic arteries (Cohen's d =0.492; CI=0.130-0.855; P=0.008) as well as significant heterogeneity (Cochran's Q =31.5; P=0.0005; I2=68.3%). Meta-regression was not performed due to the limited number of studies in the analysis. Only 2 studies investigating 18F-NaF PET imaging, and another 2 articles investigating ischemic event recurrence were found. Conclusions- Recent ipsilateral cerebral ischemia may be associated with increased carotid 18F-FDG uptake on PET imaging regardless of degree of carotid stenosis, although significant heterogeneity was found, and these results should be interpreted with caution. Emerging evidence suggests a similar association may be present with 18F-NaF plaque uptake. More studies are warranted to provide definitive conclusions on the utility of 18F-FDG or 18F-NaF in carotid plaque evaluation before investigating carotid PET as a diagnostic tool for cerebral ischemic events.

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Dataset Information

Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments.

Publications

Positron Emission Tomography After Ischemic Brain Injury: Current Challenges and Future Developments.

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