scholarly journals Reproducibility of Resting Cerebral Blood Flow Measurements with H215O Positron Emission Tomography in Humans

1993 ◽  
Vol 13 (5) ◽  
pp. 748-754 ◽  
Author(s):  
Elizabeth Matthew ◽  
Paul Andreason ◽  
Richard E. Carson ◽  
Peter Herscovitch ◽  
Karen Pettigrew ◽  
...  

Two consecutive measurements of resting CBF were carried out in normal volunteers (n = 25) using H215O positron emission tomography. Absolute whole-brain blood flow (WBBF; ml 100 g−1 min−1, mean ± SD) for the first (40.3 ± 6.4) and second (39.3 ± 6.5) measurements was not significantly different (mean % difference 2.3 ± 8.7). Analysis of regions of interest showed no significant differences in absolute regional CBF (rCBF) and normalized (rCBF/WBBF) rCBF. Left-right differences were also not significant. These data demonstrate the reproducibility of resting CBF measurements in normal humans.

1998 ◽  
Vol 18 (9) ◽  
pp. 935-940 ◽  
Author(s):  
Leif Østergaard ◽  
Peter Johannsen ◽  
Peter Høst-Poulsen ◽  
Peter Vestergaard-Poulsen ◽  
Helle Asboe ◽  
...  

In six young, healthy volunteers, a novel method to determine cerebral blood flow (CBF) using magnetic resonance (MR) bolus tracking was compared with [15O]H2O positron emission tomography (PET). The method yielded parametric CBF images with tissue contrast in good agreement with parametric PET CBF images. Introducing a common conversion factor, MR CBF values could be converted into absolute flow rates, allowing comparison of CBF values among normal subjects.


2012 ◽  
Vol 35 (6) ◽  
pp. 1290-1299 ◽  
Author(s):  
Otto M. Henriksen ◽  
Henrik B.W. Larsson ◽  
Adam E. Hansen ◽  
Julie M. Grüner ◽  
Ian Law ◽  
...  

2016 ◽  
Vol 36 (5) ◽  
pp. 842-861 ◽  
Author(s):  
Audrey P Fan ◽  
Hesamoddin Jahanian ◽  
Samantha J Holdsworth ◽  
Greg Zaharchuk

Noninvasive imaging of cerebral blood flow provides critical information to understand normal brain physiology as well as to identify and manage patients with neurological disorders. To date, the reference standard for cerebral blood flow measurements is considered to be positron emission tomography using injection of the [15O]-water radiotracer. Although [15O]-water has been used to study brain perfusion under normal and pathological conditions, it is not widely used in clinical settings due to the need for an on-site cyclotron, the invasive nature of arterial blood sampling, and experimental complexity. As an alternative, arterial spin labeling is a promising magnetic resonance imaging technique that magnetically labels arterial blood as it flows into the brain to map cerebral blood flow. As arterial spin labeling becomes more widely adopted in research and clinical settings, efforts have sought to standardize the method and validate its cerebral blood flow values against positron emission tomography-based cerebral blood flow measurements. The purpose of this work is to critically review studies that performed both [15O]-water positron emission tomography and arterial spin labeling to measure brain perfusion, with the aim of better understanding the accuracy and reproducibility of arterial spin labeling relative to the positron emission tomography reference standard.


2004 ◽  
Vol 100 (5) ◽  
pp. 1065-1071 ◽  
Author(s):  
Jaakko W. Långsjö ◽  
Elina Salmi ◽  
Kaike K. Kaisti ◽  
Sargo Aalto ◽  
Susanna Hinkka ◽  
...  

Background The authors have recently shown with positron emission tomography that subanesthetic doses of racemic ketamine increase cerebral blood flow but do not affect oxygen consumption significantly. In this study, the authors wanted to assess the effects of racemic ketamine on regional glucose metabolic rate (rGMR) in similar conditions to establish whether ketamine truly induces disturbed coupling between cerebral blood flow and metabolism. Methods 18F-labeled fluorodeoxyglucose was used as a positron emission tomography tracer to quantify rGMR on 12 brain regions of interest of nine healthy male volunteers at baseline and during a 300-ng/ml ketamine target concentration level. In addition, voxel-based analysis was performed for the relative changes in rGMR using statistical parametric mapping. Results The mean +/- SD measured ketamine serum concentration was 326.4+/-86.3 ng/ml. The mean arterial pressure was slightly increased (maximally by 16.4%) during ketamine infusion (P < 0.001). Ketamine increased absolute rGMR significantly in most regions of interest studied. The greatest increases were detected in the thalamus (14.6+/-15.9%; P = 0.029) and in the frontal (13.6+/-13.1%; P = 0.011) and parietal cortices (13.1+/-11.2%; P = 0.007). Absolute rGMR was not decreased anywhere in the brain. The voxel-based analysis revealed relative rGMR increases in the frontal, temporal, and parietal cortices. Conclusions Global increases in rGMR seem to parallel ketamine-induced increases in cerebral blood flow detected in the authors' earlier study. Therefore, ketamine-induced disturbance of coupling between cerebral blood flow and metabolism is highly unlikely. The previously observed decrease in oxygen extraction fraction may be due to nonoxidative glucose metabolism during ketamine-induced increase in glutamate release.


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