Intravenous thrombolysis in stroke patients with hyperdense middle cerebral artery sign.

BACKGROUND AND PURPOSE: We assessed the safety and efficacy of intravenous thrombolysis (IVT) in acute stroke patients with hyperdense middle cerebral artery sign (HMCAS). PATIENTS AND METHODS: Data from consecutive patients with acute (within 6 h of symptom onset) ischaemic stroke admitted between January 1999 and November 2007, in whom HMCAS was diagnosed on admission CT scan was retrospectively analysed. Seventy-one patients, admitted within the 3-h window, were treated with IVT, whilst further 42, admitted 3-6 h after symptom onset, were not. At 3-month clinical follow-up, outcome, mortality at 3 months and incidence of symptomatic intracranial haemorrhage were evaluated. RESULTS: The two groups were comparable concerning age, stroke risk factors, prior antithrombotic treatment and NIHSS scores on admission. Good outcome (mRS score

Crossed nonaphasia in a dextral with left hemispheric lesions: a functional magnetic resonance imaging study of mirrored brain organization.

BACKGROUND: General conclusions concerning mechanisms of cerebral lateralization may be learned from the investigation of functional brain organization in patients with anomalous lateralization. CASE DESCRIPTION: The functional organization of language, attention, and motor performance was investigated in a 42-year-old patient with crossed nonaphasia by means of functional MRI. The strongly right-handed man experienced a left middle cerebral artery infarction documented by MRI without exhibition of aphasia. However, the left hemispheric stroke was accompanied by visuospatial impairment, right-sided slight sensory and motor paresis, and right homonymous hemianopia. No history of familial sinistrality or prior neurological illness was present. Functional MR language mapping revealed strong right hemispheric activation in inferior frontal and superior temporal cortices. Finger tapping with the right hand recruited ipsilateral premotor and motor areas as well as supplementary motor cortex. A Stroop task, usually strongly associated with left-sided inferior frontal activation in dextrals, resulted in strong right hemispheric frontal activation. CONCLUSIONS: From our data there is clear evidence that different modalities, such as language perception and production, attention, and motor performance, are processed exclusively by 1 hemisphere when atypical cerebral dominance is present.

Cortical reafferentation following left subcortical hemorrhage: a serial functional MR study.

A 48-year-old patient who had aphasia due to a left subcortical hemorrhage underwent three follow-up examinations to assess MR signal changes accompanying recovery. A word classification task was applied. During the 6-month follow-up period, we observed a dynamic change from negative toward positive blood oxygenation level-dependent MR signals, i.e., task-related reafferentation of eloquent cortices occurred. Clinical improvement from aphasia paralleled the MR signal changes.

Intracerebral haemorrhage as a manifestation of Lyme neuroborreliosis?

Lyme Neuroborreliosis (LNB) has repeatedly been reported to cause cerebral vasculitis. However, there is no reliable information about the incidence of cerebral vessel affection. The majority of reports deal with ischaemic consequences, and there are a few reports of subarachnoid haemorrhage (SAH). We report a case of otherwise unexplained intracerebral haemorrhage (ICH) where clinical and laboratory tests have shown LNB. Late stage LNB might not only cause ischaemic, but haemorrhagic stroke as well.

Motor-learning-related changes in piano players and non-musicians revealed by functional magnetic-resonance signals.

In this study, we investigated blood-flow-related magnetic-resonance (MR) signal changes and the time course underlying short-term motor learning of the dominant right hand in ten piano players (PPs) and 23 non-musicians (NMs), using a complex finger-tapping task. The activation patterns were analyzed for selected regions of interest (ROIs) within the two examined groups and were related to the subjects' performance. A functional learning profile, based on the regional blood-oxygenation-level-dependent (BOLD) signal changes, was assessed in both groups. All subjects achieved significant increases in tapping frequency during the training session of 35 min in the scanner. PPs, however, performed significantly better than NMs and showed increasing activation in the contralateral primary motor cortex throughout motor learning in the scanner. At the same time, involvement of secondary motor areas, such as bilateral supplementary motor area, premotor, and cerebellar areas, diminished relative to the NMs throughout the training session. Extended activation of primary and secondary motor areas in the initial training stage (7-14 min) and rapid attenuation were the main functional patterns underlying short-term learning in the NM group; attenuation was particularly marked in the primary motor cortices as compared with the PPs. When tapping of the rehearsed sequence was performed with the left hand, transfer effects of motor learning were evident in both groups. Involvement of all relevant motor components was smaller than after initial training with the right hand. Ipsilateral premotor and primary motor contributions, however, showed slight increases of activation, indicating that dominant cortices influence complex sequence learning of the non-dominant hand. In summary, the involvement of primary and secondary motor cortices in motor learning is dependent on experience. Interhemispheric transfer effects are present.

Language dominance assessment by means of fMRI: contributions from task design, performance, and stimulus modality.

We investigated the influence of different task demands, task designs, and presentation modalities on the functional MRI activation patterns during a language lateralization task in a group of 14 right-handed control subjects. A word classification task was presented as target task appropriate to evoke language-related activation in the inferior frontal gyrus (IFG). The choice of the contrasting baseline task was demonstrated to have a major impact on the functional outcome: While a fixation baseline elicited activations in the inferior frontal gyrus of both hemispheres, a nonsemantic perceptual control task helped to isolate the relevant target task of word classification. The modality of stimulus presentation did not influence the functional data: Auditory and visual presentation modes broadly evoked activations in similar brain regions during word classification. Minor differences in task performance and the side of the responding hand did not interfere with the functional activation patterns of the target task. On the basis of our results, a protocol of functional lateralization in the inferior frontal gyrus is suggested. J. Magn. Reson. Imaging 2001;13:668-675.

Characterization of cerebral small vessel disease by proton spectroscopy and morphological magnetic resonance.

This study sought to investigate whether clinical and neuropsychological impairment in cerebral small vessel disease (CSVD) can be evaluated by proton spectroscopy ((1)H-MRS) and structural magnetic resonance (MR) imaging. Sixteen patients with CSVD and 15 healthy age-matched controls participated in the study. In addition to spectroscopic and structural MR examination all patients underwent a comprehensive clinical and neuropsychological investigation. Significant differences in between patients and controls were revealed by (1)H-MRS in the parietal white matter: decreased metabolic ratios of N-acetyl aspartate to choline (NAA/Cho; patients: 1.37 +/- 0.17, control: 1.72 +/- 0.25, p < 0.001) and of N-acetyl aspartate to creatin (NAA/Cr; patients: 1.41 +/- 0.15, control: 1.66 +/- 0.2, p < 0.01) indicated a pathological state. Evaluation of spectroscopic and neuropsychological data revealed a close relation between attentional impairment, i.e. delayed cerebral transmission time and decreased NAA/Cho and NAA/Cr (r = 0.62, p = 0.014). In sum, (1)H-MRS allowed a clear discrimination between patients with CSVD and age-matched normal controls. Moreover, comparisons of (1)H-MRS and neuropsychological data suggested that NAA metabolic levels, and particularly the delay in cerebral transmission time, could be potential predictors of the severeness of attentional impairment.

Impaired hemodynamics and neural activation? A fMRI study of major cerebral artery stenosis.

Functional MRI motor mapping was performed in two women with unilateral high-grade stenosis of the middle cerebral artery (MCA) to determine the influence of impaired hemodynamics on the blood oxygenation level dependent (BOLD) response. In both patients no structural lesions were present in primary motor pathways. A redistribution of the motor network to the healthy hemisphere was the main indicator of chronic hemodynamic compromise.

[Preoperative imaging as the basis for image-guided neurosurgery]. / Präoperative Bildgebung. Grundlage der navigationsgestützten Neurochirurgie.

With the progressive development of soft- and hardware, the acceptance of image-guided neurosurgery has increased dramatically. Additional image data are required to analyze the nature and the dimensions of pathological processes and the surrounding tissue. In this context, fMRI, SPECT, PET, as well as special modalities of CT and MR imaging, are routinely used. Secondary post-processing options are used to detect intracerebral lesions as well as adjacent functional eloquent regions in the parenchymatous organ pre- and intraoperatively. The integration of different image information guarantees the precise planning and realization of surgical maneuvers. The segmentation of interesting structures and risk structures, as well as their implementation in the neuronavigation systems, help to avoid additional intraoperative traumatization and offer a higher level of safety and precision. In this article the value and limitations of presurgical imaging will be discussed.

Autosomal dominant striatal degeneration (ADSD): clinical description and mapping to 5q13-5q14.

OBJECTIVE: To describe the clinical and neuroradiologic features and chromosomal mapping of a novel autosomal dominant disease affecting the basal ganglia. METHODS: The authors characterized a large family with autosomal dominant basal ganglia disease (ADSD) clinically and by MRI, MR spectroscopy (MRS), and SPECT. The authors performed a whole genome genetic linkage scan to map the underlying genetic defect. RESULTS: The main clinical features of the disease are dysarthria and gait disturbance without any apparent reduction in life expectancy. MRI demonstrated a distinctive lesion pattern restricted mainly to the putamen and caudate nucleus. Genetic linkage analysis localized the causative genetic defect to a 3.25 megabase candidate region on chromosome 5q13.3-q14.1. CONCLUSIONS: ADSD is an autosomal dominant basal ganglia disease mapping to chromosome 5q13.3-q14.1.