Do Changes in Oxygen Metabolism in the Unaffected Cerebral Hemisphere Underlie Early Neurological Recovery After Stroke?

Iglesias, S.; Marchal, G; Rioux, Patrice; Beaudouin, V.; Hauttement, J.L.; Sayette, Vincent de La; Doze, F. Le; Derlon, J M; Viader, Fausto; Baron, Jean‐Claude

doi:10.1161/01.str.27.7.1192

Cited by 57 publications

(35 citation statements)

References 48 publications

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“…This is determined both by the extent of the local increase in blood flow after brain activation and the magnitude of the increase in the cerebral metabolic rate for oxygen consumption (CMRO 2 ). 10 In our study the patients and controls showed identical behavioral performance (in the sequential finger-tapping task), and there is no evidence for a hypermetabolic state with increased CMRO 2 in patients after ischemic stroke (in fact, more typically there are decreases 23,24 ). Differences in cerebral blood volume changes also could lead to differences in BOLD response, 10 but such changes are not expected to be generalized in patients with focal infacts.…”

Section: Discussionsupporting

confidence: 46%

Altered Hemodynamic Responses in Patients After Subcortical Stroke Measured by Functional MRI

Piñeiro

Pendlebury

Johansen‐Berg

et al. 2002

Stroke

147

111

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Background and Purpose-Blood oxygenation level-dependent (BOLD) functional MRI (fMRI) is a promising method for defining brain recovery after stroke quantitatively. Applications thus far have assumed that the BOLD hemodynamic response in patients after stroke is identical to that in healthy controls. However, because of local vascular compromise or more diffuse vascular disease predisposing to infarction, this assumption may not be justified after stroke. We sought to test whether patients who have suffered a lacunar stroke show BOLD fMRI response characteristics identical to those of healthy controls. Methods-We measured the BOLD fMRI signal time course in the sensorimotor cortex contralateral to the affected hand with finger-or hand-tapping tasks for minimally or mildly impaired right-handed patients (nϭ12) after lacunar strokes causing limb weakness and for healthy controls (nϭ20). Results-With a right-handed sequential finger-tapping task, the rate of rise and maximum increase of the BOLD signal in the contralateral sensorimotor cortex were Ͼ30% lower (PՅ0.01) in the stroke patients. Similar relative decreases were found for the same task performed with the left hand. These changes were found in patients both in the hemisphere affected by stroke and in the unaffected hemisphere, suggesting that the BOLD fMRI time course differences observed arise from a diffuse functional pathology. The difference between patients and controls is not a result of age alone, since differences were not found between the younger (nϭ10; aged 22 to 38 years) and the older (nϭ10; aged 56 to 83 years) healthy controls. The effect also does not seem to be dependent on the specific hand movement task used. Conclusions-The magnitude of the BOLD fMRI response can be reduced in stroke patients even if infarcts do not involve the cortex. This may be a consequence of the stroke, but the observation that the BOLD signal time course is similar in the affected and unaffected hemispheres suggests that it also could result from preexisting pathophysiological changes in the cerebral microvasculature.

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Section: Discussionsupporting

confidence: 46%

Altered Hemodynamic Responses in Patients After Subcortical Stroke Measured by Functional MRI

Piñeiro

Pendlebury

Johansen‐Berg

et al. 2002

Stroke

147

111

View full text Add to dashboard Cite

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“…The loss of anisotropy associated with hemispheric atrophy contralateral to MCA infarcts strongly supports that secondary degeneration and demyelination spread to the contralateral hemisphere during the first 6 months after the occurrence of a MCA infarction. Only functional modifications have been previously reported in the contralateral hemisphere after MCA infarcts using SPECT (Bowler et al, 1995) or PET (Iglesias et al, 1996), the role of which in clinical recovery is now debated. Remarkably, a significant increase in FA was also detected in the hemisphere ispilateral to the ischemic lesion with histograms and a similar trend was found in the contralateral hemisphere at M3 before the final loss of anisotropy measured at M6.…”

Section: Discussionmentioning

confidence: 99%

Longitudinal Diffusion Changes in Cerebral Hemispheres after MCA Infarcts

Buffon

Molko

Hervé

et al. 2005

J Cereb Blood Flow Metab

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Diffusion tensor imaging can be used in vivo to assess the longitudinal and regional microstructural changes occurring after middle cerebral artery (MCA) infarcts in humans. Nine patients were investigated 1 week (D7), 1 (M1), 3 (M3), and 6 months (M6) after the occurrence of an isolated MCA infarction. First, an overall analysis was performed using histograms of mean diffusivity (MD) and fractional anisotropy (FA) in each hemisphere. Thereafter, the regional pattern of diffusion changes was investigated voxel by voxel with statistical parametric mapping 99. In the hemisphere ipsilateral to the infarction, histogram analysis revealed a significant decrease in FA between D7 and M6 associated with a progressive increase in MD from D7 to M3. Remote from the MCA territory, the voxel by voxel analyses detected a significant increase in MD within the thalamus at M3 and M6 and a reduction in FA along the pyramidal tract at M6. In the contralateral hemisphere, between D7 and M6, a significant hemispheric atrophy was observed in association with a global reduction in anisotropy, in the absence of distinctive regional diffusion changes. These results suggest that micro-and macrostructural tissue modifications can be detected with diffusion tensor imaging in regions remote from the ischemic area in both hemispheres.

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“…Changes in energy demands are unlikely because increase in oxygen consumption could be excluded in patients after stroke. 33 Because combined temporal changes in neural activity and cerebrovascular hemodynamics occur during recovery after brain lesion, appropriate evaluation of neural plastic changes remains challenging. In the present study, we have shown that CVR regional heterogeneities influence task-related BOLD signal in eloquent areas despite their apparent anatomical integrity but located close to an injured brain region.…”

Section: Krainik Et Al Impaired Vascular Reactivity and Bold Signal 1149mentioning

confidence: 99%

Regional Impairment of Cerebrovascular Reactivity and BOLD Signal in Adults After Stroke

Krainik

Hund-Georgiadis

Zysset

et al. 2005

Stroke

171

145

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Background and Purpose-Comparative studies across populations using functional magnetic resonance imaging (fMRI) rely on a similar relationship between blood oxygen level-dependent (BOLD) signal and neural activity. However, in elderly and patients with cerebrovascular disease, impaired cerebrovascular dynamics and neurovascular coupling may explain differences in BOLD contrast across populations and brain regions. The purpose of the study was to determine whether poststroke patients have regional heterogeneities of cerebrovascular reactivity (CVR) and their potential influence on voxel-wise motor-related BOLD signal. Methods-Using fMRI, 8 fully recovered patients from stroke in the frontal lobe without cortical lesion in the regions of interest located in the primary sensorimotor cortex (SMC), supplementary motor area (SMA), and cerebellum (CRB) were compared with 8 healthy subjects. Motor-related BOLD signal changes (%SC) were evaluated during simple unimanual and bimanual tasks, and CVR was evaluated during hyperventilation (HV). Analyses were performed using Lipsia software in SMC, SMA, and CRB. Results-In controls, amplitudes of BOLD signal were symmetrical in all regions of interest during all motor tasks and HV.In patients, %SC was decreased in SMC and SMA of the lesioned hemisphere despite their apparent anatomical integrity for all tasks. Impaired CVR was a predictor of impaired motor-related BOLD response in the SMC during contralateral movements (␤ϭϪ1.

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Do Changes in Oxygen Metabolism in the Unaffected Cerebral Hemisphere Underlie Early Neurological Recovery After Stroke?

Cited by 57 publications

References 48 publications

Altered Hemodynamic Responses in Patients After Subcortical Stroke Measured by Functional MRI

Altered Hemodynamic Responses in Patients After Subcortical Stroke Measured by Functional MRI

Longitudinal Diffusion Changes in Cerebral Hemispheres after MCA Infarcts

Regional Impairment of Cerebrovascular Reactivity and BOLD Signal in Adults After Stroke

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