scholarly journals Cerebral Blood Flow and Blood Volume Measured by Magnetic Resonance Imaging Bolus Tracking After Acute Stroke in Pigs

Stroke ◽  
2000 ◽  
Vol 31 (8) ◽  
pp. 1958-1964 ◽  
Author(s):  
Masaharu Sakoh ◽  
Lisbeth Røhl ◽  
Carsten Gyldensted ◽  
Albert Gjedde ◽  
Leif Østergaard
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Acute Stroke ◽  
Blood Volume ◽  
Resonance Imaging ◽  
Bolus Tracking

scholarly journals Cerebral Blood Flow, Blood Volume, and Oxygen Metabolism Dynamics in Human Visual and Motor Cortex as Measured by Whole-Brain Multi-Modal Magnetic Resonance Imaging

2009 ◽  
Vol 29 (11) ◽  
pp. 1856-1866 ◽  
Author(s):  
Manus J Donahue ◽  
Jakob U Blicher ◽  
Leif Østergaard ◽  
David A Feinberg ◽  
Bradley J MacIntosh ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Visual Cortex ◽  
Magnetic Resonance ◽  
Motor Cortex ◽  
Blood Volume ◽  
Bold Signal ◽  
Resonance Imaging ◽  
Whole Brain

The development of neuroimaging methods to characterize flow-metabolism coupling is crucial for understanding mechanisms that subserve oxygen delivery. Functional magnetic resonance imaging (fMRI) using blood-oxygenation-level-dependent (BOLD) contrast reflects composite changes in cerebral blood volume (CBV), cerebral blood flow (CBF), and the cerebral metabolic rate of oxygen consumption (CMRO2). However, it is difficult to separate these parameters from the composite BOLD signal, thereby hampering MR-based flow-metabolism coupling studies. Here, a novel, noninvasive CBV-weighted MRI approach (VASO-FLAIR with 3D GRASE (GRadient-And-Spin-Echo)) is used in conjunction with CBF-weighted and BOLD fMRI in healthy volunteers ( n=7) performing simultaneous visual (8 Hz flashing-checkerboard) and motor (1 Hz unilateral joystick) tasks. This approach allows for CBV, CBF, and CMRO2 to be estimated, yielding (mean±s.d.): ΔCBF=63%±12%, ΔCBV=17%±7%, and ΔCMRO2=13%±11% in the visual cortex, and ΔCBF=46%±11%, ΔCBV=8%±3%, and ΔCMRO2=12%±13% in the motor cortex. Following the visual and motor tasks, the BOLD signal became more negative ( P=0.003) and persisted longer ( P=0.006) in the visual cortex compared with the motor cortex, whereas CBV and CBF returned to baseline earlier and equivalently. The proposed whole-brain technique should be useful for assessing regional discrepancies in hemodynamic reactivity without the use of intravascular contrast agents.

scholarly journals Relation between Relative Cerebral Blood Flow, Relative Cerebral Blood Volume, and Mean Transit Time in Patients with Acute Ischemic Stroke Determined by Perfusion-Weighted MRI

2003 ◽  
Vol 23 (5) ◽  
pp. 605-611 ◽  
Author(s):  
Oliver C. Singer ◽  
Richard du Mesnil de Rochemont ◽  
Christian Foerch ◽  
Astrid Stengel ◽  
Heiner Lanfermann ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Blood Volume ◽  
Cerebral Blood Volume ◽  
Mean Transit Time ◽  
Resonance Imaging ◽  
Unaffected Side ◽  
Weighted Magnetic Resonance Imaging

The relation between relative cerebral blood flow (relCBF), relative cerebral blood volume (relCBV), and mean transit time (MTT) changes was examined in 20 patients with acute cerebral ischemia (<6 h) using perfusion-weighted magnetic resonance imaging. Regions of interest (ROI) were selected on MTT maps covering the entire MTT abnormal cortical area. These ROIs were transferred to the relCBF and relCBV maps to analyze the relation between relCBF, relCBV, and MTT on a voxel-by-voxel basis. On the unaffected side, a tight coupling of relCBF and relCBV was found with little variation of MTT. In hypoperfused cortex, relCBV was increased at all investigated relCBF categories, and there was greater relCBV variability than on the unaffected side. Only a severe decrease of relCBF, to less than 0.3, in comparison with the unaffected side was associated with a reduction of relCBV less than 1.0. In contrast to the unaffected side, a power law function (relCBV = 2.283 × relCBF0.549) resulted in a better fit than using a linear function for the correlation of relCBF and relCBV. MTT ratios increased steadily with decreasing CBF values. In conclusion, there is a clear relation between different perfusion-weighted magnetic resonance imaging parameters in acute ischemia, reflecting both the degree of hemodynamic failure as well as compensatory mechanisms including vasodilation.

scholarly journals Absolute Cerebral Blood Flow and Blood Volume Measured by Magnetic Resonance Imaging Bolus Tracking: Comparison with Positron Emission Tomography Values

1998 ◽  
Vol 18 (4) ◽  
pp. 425-432 ◽  
Author(s):  
Leif Østergaard ◽  
Donald F. Smith ◽  
Peter Vestergaard-Poulsen ◽  
SørenB. Hansen ◽  
Antony D. Gee ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Positron Emission Tomography ◽  
Blood Flow ◽  
Cerebral Blood Flow ◽  
Magnetic Resonance ◽  
Blood Volume ◽  
Emission Tomography ◽  
Resonance Imaging ◽  
Positron Emission ◽  
O 15

The authors determined cerebral blood flow (CBF) with magnetic resonance imaging (MRI) of contrast agent bolus passage and compared the results with those obtained by O-15 labeled water (H215O) and positron emission tomography (PET). Six pigs were examined by MRI and PET under normo- and hypercapnic conditions. After dose normalization and introduction of an empirical constant ΦGd, absolute regional CBF was calculated from MRI. The spatial resolution and the signal-to-noise ratio of CBF measurements by MRI were better than by the H215O-PET protocol. Magnetic resonance imaging cerebral blood volume (CBV) estimates obtained using this normalization constant correlated well with values obtained by O-15 labeled carbonmonooxide (C15O) PET. However, PET CBV values were approximately 2.5 times larger than absolute MRI CBV values, supporting the hypothesized sensitivity of MRI to small vessels.

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