multi-tracer-studies-brain-oxygen-glucose-metabolism-using-time

Multi-Tracer Studies of Brain Oxygen and Glucose Metabolism Using a Time-of-Flight Positron Emission Tomography-Computed Tomography Scanner

The authors have developed a paradigm using positron emission tomography (PET) with multiple radiopharmaceutical tracers that combines measurements of ...

Washington University School of Medicine

The purpose was to test the hypothesis that increased oxygen extraction fraction (OEF), a marker of severe hemodynamic impairment measured by positron emission tomography, is an independent risk factor for subsequent ischemic stroke in this population.

Baseline Hemodynamic Impairment and Future Stroke Risk in Adult Idiopathic Moyamoya Phenomenon: Results of a Prospective Natural History Study.

Research of the human brain metabolism in vivo has largely focused on total glucose use (via fluorodeoxyglucose positron emission tomography) and, until recently, did not examine the use of glucose outside oxidative phosphorylation, which is known as aerobic glycolysis (AG). AG supports important functions including biosynthesis and neuroprotection but decreases dramatically with aging. This multitracer positron emission tomography study evaluated the relationship between AG, total glucose use (CMRGlc), oxygen metabolism (CMRO), tau, and amyloid deposition in 42 individuals, including those at preclinical and symptomatic stages of Alzheimer's disease. Our findings demonstrate that in individuals with amyloid burden, lower AG is associated with higher tau deposition. No such correlation was observed for CMRGlc or CMRO. We suggest that aging-related loss of AG leading to decreased synaptic plasticity and neuroprotection may accelerate tauopathy in individuals with amyloid burden. Longitudinal AG and Alzheimer's disease pathology studies are needed to verify causality.

Aerobic glycolysis and tau deposition in preclinical Alzheimer's disease.

Delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) may result in focal neurological deficits and cerebral infarction, believed to result from critical regional rather than global impairments in cerebral blood flow (CBF). However, the burden of such regional hypoperfusion has not been evaluated by gold-standard voxel-by-voxel CBF measurements. Specifically, the authors sought to determine whether the proportion of brain affected by hypoperfusion was greater in patients with DCI than in SAH controls without DCI and whether the symptomatic hemisphere (in those with lateralizing deficits) exhibited a greater cerebral hypoperfusion burden.

Burden of cerebral hypoperfusion in patients with delayed cerebral ischemia after subarachnoid hemorrhage.

White matter hyperintensities (WMH) are nearly ubiquitous in the aging brain, and their topography and overall burden are associated with cognitive decline. Given their numerosity, accurate methods to automatically segment WMH are needed. Recent developments, including the availability of challenge data sets and improved deep learning algorithms, have led to a new promising deep-learning based automated segmentation model called TrUE-Net, which has yet to undergo rigorous independent validation. Here, we compare TrUE-Net to six established automated WMH segmentation tools, including a semi-manual method. We evaluated the techniques at both global and regional level to compare their ability to detect the established relationship between WMH burden and age. We found that TrUE-Net was highly reliable at identifying WMH regions with low false positive rates, when compared to semi-manual segmentation as the reference standard. TrUE-Net performed similarly or favorably when compared to the other automated techniques. Moreover, TrUE-Net was able to detect relationships between WMH and age to a similar degree as the reference standard semi-manual segmentation at both the global and regional level. These results support the use of TrUE-Net for identifying WMH at the global or regional level, including in large, combined datasets.

Hussain Jafri

Mallinckrodt Institute of Radiology

Washington University School of Medicine

Multi-Tracer Studies of Brain Oxygen and Glucose Metabolism Using a Time-of-Flight Positron Emission Tomography-Computed Tomography Scanner

Hussain Jafri

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Washington University School of Medicine

Multi-Tracer Studies of Brain Oxygen and Glucose Metabolism Using a Time-of-Flight Positron Emission Tomography-Computed Tomography Scanner

Mallinckrodt Institute of Radiology