Oxygen Extraction Fraction and Stroke Risk in Patients with Carotid Stenosis or Occlusion: A Systematic Review and Meta-Analysis

Gupta, Ajay; Baradaran, Hediyeh; Schweitzer, Andrew D.; Kamel, Hooman; Pandya, Ankur; Delgado, Diana; Wright, Drew; Hurtado-Rúa, Sandra; Wang, Y.; Sanelli, Pina C.

doi:10.3174/ajnr.a3668

Cited by 48 publications

(55 citation statements)

References 21 publications

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“…Here, P is the preconditioner defined as P ¼ diag CMRO 2;ub ; avgðxÞ , which is designed to allow the elements of x P to have similar order of magnitude. CMRO 2;ub is the upper bound of CMRO 2 calculated within each block using Equations [1] and [2] using OEF ¼ 1 and avgðxÞ denotes the average of susceptibility of voxels within a block that are of the same tissue type.…”

Section: Reconstruction Of Cmro 2 and Oefmentioning

confidence: 99%

Quantitative susceptibility mapping‐based cerebral metabolic rate of oxygen mapping with minimum local variance

Zhang

Cho

Zhou

et al. 2017

Magnetic Resonance in Med

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Purpose: The objective of this study was to demonstrate the feasibility of a cerebral metabolic rate of oxygen (CMRO 2 ) mapping method based on its minimum local variance (MLV) without vascular challenge using quantitative susceptibility mapping (QSM) and cerebral blood flow (CBF). Methods: Three-dimensional multi-echo gradient echo imaging and arterial spin labeling were performed in 11 healthy subjects to calculate QSM and CBF. Minimum local variance was used to compute whole-brain CMRO 2 map from QSM and CBF. The MLV method was compared with a reference method using the caffeine challenge. Their agreement within the cortical gray matter (CGM) was assessed on CMRO 2 and oxygen extraction fraction (OEF) maps at both baseline and challenge states. Results: Mean CMRO 2 (in mmol/100 g/min) obtained in CGM using the caffeine challenge and MLV were 142 6 16.5 and 139 6 14.8 mmol/100 g/min, respectively; the corresponding baseline OEF were 33.0 6 4.0% and 31.8 6 3.2%, respectively. The MLV and caffeine challenge methods showed no statistically significant differences across subjects with small ( < 4%) biases in CMRO 2 and OEF values. Conclusions: Minimum local variance-based CMRO 2 mapping without vascular challenge using QSM and arterial spin labeling is feasible in healthy subjects. Magn Reson Med 79:172-179,

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Section: Reconstruction Of Cmro 2 and Oefmentioning

confidence: 99%

Quantitative susceptibility mapping‐based cerebral metabolic rate of oxygen mapping with minimum local variance

Zhang

Cho

Zhou

et al. 2017

Magnetic Resonance in Med

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“…Thus positron-labeled compounds are used in combination with PET imaging to obtain biological information of living systems in research and clinical settings. For instance, 15 O labeled O 2 gas PET has been used to estimate cerebral oxygen metabolism in patients for diagnostic purposes since the 1970s [7–12]. Although the 15 O-O 2 gas PET technique also attracted researchers for the evaluation of cerebral oxygen metabolism in small animals, it was applied unsuccessfully due to technical challenges until the 1990s.…”

Section: Introductionmentioning

confidence: 99%

PET Quantification of Cerebral Oxygen Metabolism in Small Animals

Temma

Koshino

Moriguchi

et al. 2014

The Scientific World Journal

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Understanding cerebral oxygen metabolism is of great importance in both clinical diagnosis and animal experiments because oxygen is a fundamental source of brain energy and supports brain functional activities. Since small animals such as rats are widely used to study various diseases including cerebral ischemia, cerebrovascular diseases, and neurodegenerative diseases, the development of a noninvasive in vivo measurement method of cerebral oxygen metabolic parameters such as oxygen extraction fraction (OEF) and cerebral metabolic rate of oxygen (CMRO2) as well as cerebral blood flow (CBF) and cerebral blood volume (CBV) has been a priority. Although positron emission tomography (PET) with 15O labeled gas tracers has been recognized as a powerful way to evaluate cerebral oxygen metabolism in humans, this method could not be applied to rats due to technical problems and there were no reports of PET measurement of cerebral oxygen metabolism in rats until an 15O-O2 injection method was developed a decade ago. Herein, we introduce an intravenous administration method using two types of injectable 15O-O2 and an 15O-O2 gas inhalation method through an airway placed in the trachea, which enables oxygen metabolism measurements in rats.

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“…On the basis of such measurements, 3 stages of hemodynamic compromise have been proposed (45,77): stage 0, in which collateral circulation completely compensates for the occluded artery; stage I (hemodynamic compromise), in which CBV is increased but CBF response to vasodilatory stimuli is decreased and OEF remains normal; and stage II (hemodynamic failure), in which CBF is reduced and OEF is increased to preserve CMRO 2 in order to cover the metabolic demands of the tissue. Abnormal OEF is a powerful predictor of subsequent ipsilateral stroke (78). Repeated PET scanning before and after carotid artery stenting has revealed improvements in CBF, perfusion pressure, and CMRO 2 (79), and stabilization of the hemodynamic situation has been demonstrated by SPECT (Fig.…”

Section: Hemodynamic and Metabolic Reserve In Arterial Occlusive Diseasementioning

confidence: 96%

Radionuclide Imaging in Ischemic Stroke

Heiss

2014

J Nucl Med

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Learning Objectives: On successful completion of this activity, participants should be able to describe (1) the physiologic and metabolic variables relevant for brain function and the radionuclides and methods to measure these variables in cerebrovascular disease, especially ischemic stroke; (2) the radionuclide methods to determine the thresholds of flow and metabolism relevant for preservation of function and morphology and the obtained values in their relevance to prognosis and potential treatment; and (3) the applications of radionuclide imaging for identifying pathophysiologic changes responsible for extension of ischemic lesions, for defining the hemodynamic reserve in vascular disease, for detecting remote effects outside the primary lesions, and for locating compensatory activation in disturbed functional networks.Financial Disclosure: Dr. Heiss is supported by the Wolf-Dieter Heiss Foundation within the Max Planck Society. The author of this article has indicated no other relevant relationships that could be perceived as a real or apparent conflict of interest. CME Credit: SNMMI is accredited by the Accreditation Council for Continuing Medical Education (ACCME) to sponsor continuing education for physicians. SNMMI designates each JNM continuing education article for a maximum of 2.0 AMA PRA Category 1 Credits. Physicians should claim only credit commensurate with the extent of their participation in the activity. For CE credit, SAM, and other credit types, participants can access this activity through the SNMMI website (http://www.snmmilearningcenter.org) through November 2017.Ischemic stroke is caused by interruption or significant impairment of blood supply to the brain, which leads to a cascade of metabolic and molecular alterations resulting in functional disturbance and morphologic damage. The changes in regional cerebral blood flow and regional metabolism can be assessed by radionuclide imaging, especially SPECT and PET. SPECT and PET have broadened our understanding of flow and metabolic thresholds critical for maintenance of brain function and morphology: PET was essential in the transfer of the concept of the penumbra to clinical stroke and thereby had a great impact on developing treatment strategies. Receptor ligands can be applied as early markers of irreversible neuronal damage and can predict the size of the final infarcts, which is important for decisions on invasive therapy in large ("malignant") infarction. With SPECT and PET, the reserve capacity of the blood supply can be tested in obstructive arteriosclerosis, which is essential for planning interventions. The effect of a stroke on surrounding and contralateral primarily unaffected tissue can be investigated, helping to understand symptoms caused by disturbance in functional networks. Activation studies are useful to demonstrate alternative pathways to compensate for lesions and to test the effect of rehabilitative therapy. Radioisotope studies help to detect neuroinflammation and its effect on extension of tissue damage. Despite the...

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Oxygen Extraction Fraction and Stroke Risk in Patients with Carotid Stenosis or Occlusion: A Systematic Review and Meta-Analysis

Cited by 48 publications

References 21 publications

Quantitative susceptibility mapping‐based cerebral metabolic rate of oxygen mapping with minimum local variance

Quantitative susceptibility mapping‐based cerebral metabolic rate of oxygen mapping with minimum local variance

PET Quantification of Cerebral Oxygen Metabolism in Small Animals

Radionuclide Imaging in Ischemic Stroke

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