Metabolic Profile Of Motor Cortex In Stroke (original) (raw)
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Primary Motor Cortex in Stroke: A Functional MRI-Guided Proton MR Spectroscopic Study
Stroke, 2011
Background and Purpose-Our goal was to investigate whether certain metabolites, specific to neurons, glial cells, or the neuronal-glial neurotransmission system, in primary motor cortices (M1), are altered and correlated with clinical motor severity in chronic stroke. Methods-Fourteen survivors of a single ischemic stroke located outside the M1 and 14 age-matched healthy control subjects were included. At Ͼ6 months after stroke, N-acetylaspartate, myo-inositol, and glutamate/glutamine were measured using proton magnetic resonance spectroscopic imaging (in-plane resolutionϭ5ϫ5 mm 2 ) in radiologically normal-appearing gray matter of the hand representation area, identified by functional MRI, in each M1. Metabolite concentrations and analyses of metabolite correlations within M1 were determined. Relationships between metabolite concentrations and arm motor impairment were also evaluated. Results-The stroke survivors showed lower N-acetylaspartate and higher myo-inositol across ipsilesional and contralesional M1 compared with control subjects. Significant correlations between N-acetylaspartate and glutamate/glutamine were found in either M1. Ipsilesional N-acetylaspartate and glutamate/glutamine were positively correlated with arm motor impairment and contralesional N-acetylaspartate with time after stroke.
Motor and Premotor Cortices in Subcortical Stroke
Neurorehabilitation and Neural Repair, 2013
Background. Although functional imaging and neurophysiological approaches reveal alterations in motor and premotor areas after stroke, insights into neurobiological events underlying these alterations are limited in human studies. Objective. We tested whether cerebral metabolites related to neuronal and glial compartments are altered in the hand representation in bilateral motor and premotor areas and correlated with distal and proximal arm motor impairment in hemiparetic persons. Methods. In 20 participants at >6 months postonset of a subcortical ischemic stroke and 16 age- and sex-matched healthy controls, the concentrations of N-acetylaspartate and myo-inositol were quantified by proton magnetic resonance spectroscopy. Regions of interest identified by functional magnetic resonance imaging included primary (M1), dorsal premotor (PMd), and supplementary (SMA) motor areas. Relationships between metabolite concentrations and distal (hand) and proximal (shoulder/elbow) motor impai...
Neurorehabilitation and Neural Repair, 2013
Background-Abnormal task-related activation in primary motor cortices (M1) has been consistently found in functional imaging studies of subcortical stroke. Whether the abnormal activations are associated with neuronal alterations in the same or homologous area is not known. Objective-Our goal was to establish the relationships between M1 measures of motor taskrelated activation and a neuronal marker, N-acetylaspartate, in patients with severe to mild hemiparesis. Methods-Eighteen survivors of an ischemic subcortical stroke (confirmed on T2-weighted images) at more than six months post-onset and sixteen age-and sex-matched right-handed healthy controls underwent functional MRI during a handgrip task (impaired hand in patients, dominant hand in controls) and proton magnetic resonance spectroscopy (1 H-MRS) imaging. Spatial extent and magnitude of blood oxygen level-dependent response (or activation) and N-*
Neuronal–glial alterations in non-primary motor areas in chronic subcortical stroke
Brain Research, 2012
Whether functional changes of the non-primary motor areas, e.g., dorsal premotor (PMd) and supplementary motor (SMA) areas, after stroke, reflect reorganization phenomena or recruitment of a pre-existing motor network remains to be clarified. We hypothesized that cellular changes in these areas would be consistent with their involvement in post-stroke reorganization. Specifically, we expected that neuronal and glial compartments would be altered in radiologically normalappearing, i.e., spared, PMd and SMA in patients with arm paresis. Twenty survivors of a single ischemic subcortical stroke and 16 age-matched healthy controls were included. At more than six months after stroke, metabolites related to neuronal and glial compartments: N-acetylaspartate, myo-inositol, and glutamate/glutamine, were quantified by proton magnetic resonance spectroscopy in PMd and SMA in both injured (ipsilesional) and un-injured (contralesional) hemispheres. Correlations between metabolites were also calculated. Finally, relationships between metabolite concentrations and arm motor impairment (total and proximal Fugl-Meyer Upper Extremity, FMUE, scores) were analyzed. Compared to controls, stroke survivors showed significantly higher ipsilesional PMd myo-inositol and lower SMA N-acetylaspartate.
International journal of physical medicine & rehabilitation, 2016
We investigated the effects of an intensive impairment-oriented training on neuronal state (assessed by proton MR spectroscopy, 1H-MRS) of the spared motor and premotor cortices in the injured (ipsilesional) hemisphere and clinical impairment in a patient with chronic subcortical stroke. One survivor of a single ischemic stroke located outside of the motor and premotor cortices (assessed on T1-weighted MRI) was studied at six months after stroke. We used functional MRI-guided 1H-MRS to quantify the levels of N-acetylaspartate (NAA - a putative neuronal marker) in the hand representation within ipsilesional primary motor cortex (M1), dorsal premotor cortex (dPM) and supplementary motor area (SMA), and Fugl-Meyer (normal=66 points) test to assess the arm motor impairment immediately before and after a motor training paradigm. Training comprised intensive variable practice (1080 repetitions over 12 day-period) of a reach-to-grasp task with the impaired hand while focusing the learner&#...
Diagnostics
Preservation of neuronal tissue is crucial for recovery after stroke, but studies suggest that prolonged neuronal loss occurs following acute ischaemia. This study assessed the temporal pattern of neuronal loss in subacute ischemic stroke patients using 1H magnetic resonance spectroscopy, in parallel with functional recovery at 2, 6 and 12 weeks after stroke. Specifically, we measured N-acetylaspartate (NAA), choline, myoinositol, creatine and lactate concentrations in the ipsilesional and contralesional thalamus of 15 first-ever acute ischaemic stroke patients and 15 control participants and correlated MRS concentrations with motor recovery, measured at 12 weeks using the Fugl–Meyer scale. NAA in the ipsilesional thalamus fell significantly between 2 and 12 weeks (10.0 to 7.97 mmol/L, p = 0.003), while choline, myoinositol and lactate concentrations increased (p = 0.025, p = 0.031, p = 0.001, respectively). Higher NAA concentrations in the ipsilesional thalamus at 2 and 12 weeks co...
Stroke, 1993
Background and Purpose: Proton magnetic resonance spectroscopy has documented declines in normal metabolites and long-term elevation of lactate signal after stroke in humans. Within days of stroke, leukocytes infiltrating the infarct zone may produce much of the lactate seen in the subacute and chronic periods. Methods: We examined 10 patients by localized proton magnetic resonance spectroscopy with onedimensional spectroscopic imaging within the first 60 hours after acute nonhemorrhagic cerebral infarction, a period before abundant leukocyte infiltration. Follow-up studies on day 8 to 17 after stroke were performed on 7 of these patients. Results: Initially, the lactate magnetic resonance signal was elevated in all patients. The N-acetylaspartate peak within the lesion was reduced below contralateral normal brain in all but two. At subsequent examination, significant declines had occurred in lesion maximum lactate and N-acetylaspartate signals, with average changes of-36±11% per week and-29±9%O per week, respectively. Declines in lesion creatine/phosphocreatine and in choline-containing compound peaks occurred in some patients but did not attain statistical significance for the group as a whole. Estimated lesion volume correlated positively with both total (r=.75, P=.012) and lesion maximum (r=.74, P=.015) lactate signal. Conclusions: Elevated lactate signal is reliably detectable by magnetic resonance spectroscopy after acute cerebral infarction in humans. Clearance of lactate occurs despite the potential contribution of lactate-producing leukocytes in the subacute stage. Delayed loss of N-acetyl-aspartate signal in second examinations suggests that late death of viable cells may occur within the first 2 weeks after cerebral infarction. (Stroke. 1993;24:1891-1896.) KEY WoRDs * cerebral infarction * lactates * nuclear magnetic resonance
2010
Background and Purpose-Infarct size on T2-weighted MRI correlates only modestly with outcome, particularly for small strokes. This may be largely because of differences in the locations of infarcts and consequently in the functional pathways that are damaged. To test this hypothesis quantitatively, we developed a "mask" of the corticospinal pathway to determine whether the extent of stroke intersection with the pathway would be more closely related to clinical motor deficit and axonal injury in the descending motor pathways than total stroke lesion volume. Methods-Eighteen patients were studied Ն1 month after first ischemic stroke that caused a motor deficit by use of brain T2-weighted imaging, MR spectroscopic (MRS) measurements of the neuronal marker compound N-acetyl aspartate in the posterior limb of the internal capsule, and motor impairment and disability measures. A corticospinal mask based on neuroanatomic landmarks was generated from a subset of the MRI data. The maximum proportion of the cross-sectional area of this mask occupied by stroke was determined for each patient after all brain images were transformed into a common stereotaxic brain space. Results-There was a significant linear relationship between the maximum proportional cross-sectional area of the corticospinal mask occupied by stroke and motor deficit (r 2 ϭ0.82, PϽ0.001), whereas the relationship between the total stroke volume and motor deficit was better described by a cubic curve (r 2 ϭ0.76, PϽ0.001). Inspection of the data plots showed that the total stroke volume discriminated poorly between smaller strokes with regard to the extent of associated motor deficit, whereas the maximum proportion of the mask cross-sectional area occupied by stroke appeared to be a more discriminatory marker of motor deficit and also N-acetyl aspartate reduction. Conclusions-Segmentation of functional motor pathways on MRI allows estimation of the extent of damage specifically to that pathway by the stroke lesion. The extent of stroke intersection with the motor pathways was more linearly related to the magnitude of motor deficit than total lesion volume and appeared to be a better discriminator between small strokes with regard to motor deficit. This emphasizes the importance of the anatomic relationship of the infarct to local structures in determining functional impairment. Prospective studies are necessary to assess whether this approach would allow improved early estimation of prognosis after stroke. (Stroke. 2000;31:672-679.)
2006
BACKGROUND AND PURPOSE: Ensuring the translatability of primate stroke models is critical for preclinical testing of cerebroprotective strategies, and such models would benefit from further characterization of the experimental ischemic tissue. Our purpose was to examine the cerebral metabolic response to stroke in baboons with MR spectroscopy and to correlate metabolite levels with functional neurologic outcomes. METHODS: Seven baboons underwent 1 hour of middle cerebral artery occlusion. At 3 and 10 days, each animal was imaged with traditional MR imaging and multivoxel proton 1 H-MR spectroscopy, and a neurologic examination was performed. Spectra obtained from the infarcted hemisphere of each animal were compared with the contralateral hemisphere, and metabolite levels were correlated with neurologic outcome scores. RESULTS: Spectra obtained at 3 days postischemia revealed prominent lactate (LAC) resonances and attenuated N-acetylaspartate (NAA) peaks in infarcted hemispheres. Te...