摘要:

AbstractAn image–processing strategy for functional magnetic resonance imaging (fMRI) data sets consisting of sequential images of the same slice of brain tissue is considered. An algorithm of detection based on the likelihood–ratio test and the noise properties in fMRI is introduced. Since the data have a poor signal–to–noise ratio, and in order to make detection reliable, the algorithm is organized in two steps: (1) pixel detection, which detects all pixels having significant changes, thus building regions of interest (ROIs), and (2) region detection, which selects the most likely activated region from obtained ROIs. The detection method is applied to experimental fMRI data from the motor cortex and compared with the cross–correlation method and Student's t test commonly applied by others. The results obtained using the likelihood–ratio test show improvement in the detection of activated regions.

ISSN:1051-2284    

DOI:10.1111/jon199664207

出版商:Wiley    

年代:1996

数据来源: WILEY

ISSN:1051-2284    

DOI:10.1111/jon199664213

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractAicardi's syndrome consists of multiple anomalies of the eye, brain, and axial skeleton in females, and is associated with early‐onset infantile spasms and severe developmental delay. For the present study, magnetic resonance images of 20 patients with Aicardi's syndrome were obtained and the neuroimaging findings catalogued. These were compared to previously reported results and the findings correlated with current theories of fetal brain development. The results revealed a high frequency of cortical migration defects (94%) and a wide variability in the callosal defect, migrational abnormalities, and other findings in Aicardi's syndrome.

ISSN:1051-2284    

DOI:10.1111/jon199664214

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractCorticobasal degeneration (CBD) is an adult–onset, progressive parkinsonian syndrome with strikingly asymmetrical features, and signs and symptoms referable to both cerebral cortex and basal ganglia. Although once considered rare, it is now recognized with increasing frequency during life. Eight patients with clinically diagnosed CBD and 8 age– and sex–matched patients with Parkinson's disease underwent high–field–strength magnetic resonance imaging (MRI) of the brain. MRIs were graded by a blinded neuroradiologist using a semiquantitative (0–3) scale. MRI of patients with CBD revealed significantly greater T2–weighted signal hypointensity in the putamena and globi pallidi, and ventricular enlargement. When specifically sought, asymmetrical cortical atrophy was identified in 5 of 8 CBD patients. Increased T2–weighted lenticular signal hypointensity, ventricular enlargement, and asymmetrical cortical atrophy are supportive MRI findings of CBD.

ISSN:1051-2284    

DOI:10.1111/jon199664222

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractTranscranial color‐coded duplex sonography is a recently introduced method for visualizing (1) the blood flow velocity of the basal cerebral arteries and (2) the brain parenchyma as an acoustic impedance image. Dislocation of the third ventricle due to space‐occupying stroke is an important clinical marker. This study evaluated the dislocation of the third ventricle from the brain midline by transcranial duplex sonography in 10 healthy volunteers. The mean dislocation was 0.2 ± 0.3 mm. Eighteen stroke patients were investigated within 12 hours by both duplex sonography and computed tomography (CT) and the dislocation of the third ventricle was measured. Correlation between the two methods was high (r= 0.87,N= 27). Twelve stroke patients divided into three subgroups according to the extent of the space‐occupying effects of the lesion were followed for 3 weeks. The increase and decrease of the dislocation of the third ventricle over the time were monitored. In conclusion, transcranial duplex sonography is a reliable tool to monitor dislocation of the third ventricle due to space‐occupying stroke.

ISSN:1051-2284    

DOI:10.1111/jon199664227

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractMagnetic resonance imaging (MRI)–based volumetric measurements of the hippocampus and amygdala are useful in detecting hippocampal and amygdaloid sclerosis in patients with temporal lobe epilepsy. In these pathological entities, volumetric MRI analysis shows the epileptogenic structures to be atrophic when compared to the normal, nonepileptogenic side. Described are 2 patients with increased hippocampal and amygdaloid volumes on the side of seizure onset due to medial temporal lobe heterotopias. Care must be taken in the interpretation of volumetric MRI data to make certain that asymmetries in hippocampal and amygdaloid measurements are due to atrophy and sclerosis of the abnormal side and not to increased tissue such as heterotopic gray matter.

ISSN:1051-2284    

DOI:10.1111/jon199664231

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractAlterations in midsagittal corpus callosum (CC) area and morphology have been suggested in several disease processes of the nervous system. In addition, some studies found a relation of CC area to handedness, language dominance, and gender. The relation of CC area to measures of intelligence and memory and the effect of epilepsy on CC area have received less attention. In this study CC area was measured on midsagittal magnetic resonance images in 48 patients undergoing presurgical evaluation of epilepsy and in 20 control subjects. All patients had the Wada test and formal neuropsychological testing. The mean CC area of the epilepsy group was significantly smaller than that of control subjects (p<0.00001). CC area showed a positive correlation with presurgical performance IQ (p = 0.008) and full‐scale IQ (p = 0.048), but not with memory scores or language dominance. There was no relation of CC area to location of epileptic focus, seizure types, age at onset, epilepsy duration, or etiology. The presence of an atrophic lesion was associated with a smaller CC area. The correlation of total CC area with performance and full‐scale IQs may reflect axonal loss in patients with a low IQ, resulting from the etiology of epilepsy or the epilepsy itself.

ISSN:1051-2284    

DOI:10.1111/jon199664235

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractSeven patients with acute or chronic unilateral hypoglossal nerve lesions were evaluated by magnetic resonance imaging and computed tomography. In patients with acute to subacute tongue paralysis, the base of the ipsilateral side of the tongue appeared expanded and showed increased signal intensity on T2‐weighted images. This appearance was suggestive of an infiltrative mass lesion within the tongue. These radiographic findings are due to the pathophysiological process of nerve injury and muscle denervation.

ISSN:1051-2284    

DOI:10.1111/jon199664240

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractSingle–photon emission computed tomography (SPECT) and transcranial Doppler (TCD) ultrasonography were used to assess brain perfusion during cardiopulmonary bypass. Intravenous injections of technetium 99 m–hexamethylpropyleneamineoxime (99mTc–HMPAO) were administered before surgery and intraoperatively after the first 2 minutes in the first patient and at the end (42 minutes) of cardiopulmonary bypass in the second patient. The total middle cerebral artery territory counts were calculated using the region–of–interest method and compared to cerebellar regional counts. 99mTc–HMPAO uptake on SPECT scans was increased at the beginning and at the end of cardiopulmonary bypass, compared to baseline preoperative values (11–17%) in the presence of multiple microembolic signals on TCD (n, = 35 and n2 = 42 for unilateral middle cerebral artery monitoring). These results indicate the feasibility of using HMPAO–SPECT to study brain perfusion changes during cardiac surgery. A combination of SPECT and TCD ultrasonography may be used to study the impact of microembolism during cardiac surgery with cardiopulmonary bypass.

ISSN:1051-2284    

DOI:10.1111/jon199664243

出版商:Wiley    

年代:1996

数据来源: WILEY

摘要:

AbstractDescribed herein is a patient with Wilson's disease who had tremor as a prominent neurological manifestation. T2‐weighted magnetic resonance imaging showed abnormal high signal intensities in the bilateral lenticular nuclei, thalami, and red nuclei of the midbrain. Improvement of tremor with copper chelating agents was well correlated with a decrease of the abnormal signals in the thalami and the red nuclei.

ISSN:1051-2284    

DOI:10.1111/jon199664246

出版商:Wiley    

年代:1996

数据来源: WILEY