摘要:

Six normal volunteers underwent 4‐T functional magnetic resonance imaging while performing a covert letter fluency task. An echo planar imaging sequence was utilized to detect activation based on deoxyhemoglobin contrast. All 6 subjects showed consistent activation in the frontal operculum and premotor and primary motor cortices. Activation was also detected in the supramarginal gyrus and the posterior part of the superior temporal gyrus. These results show that magnetic resonance functional neuroimaging can be used to investigate cerebral activity noninvasively during performance of complex cognitive tasks.

ISSN:1051-2284    

DOI:10.1111/jon19944267

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Twenty‐one patients at different clinical stages of subacute sclerosing panencephalitis were studied by magnetic resonance imaging and computed tomography. In patients in the early clinical stage, the imaging studies appeared normal. Within 6 months, diffuse or focal areas of high signal on T2‐weighted magnetic resonance images were evident. Progressive hemispheric, cerebellar, and brainstem atrophy was seen later. Lesions of the deep nuclei were noted frequently in patients in the early and intermediate stages, with the lentiform involved more than the caudate. Magnetic resonance imaging was better than computed tomography in illustrating white matter and basal ganglia abnormalities. Radiographic progression occurred regardless of clinical course.

ISSN:1051-2284    

DOI:10.1111/jon19944271

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Transcranial duplex color‐flow imaging is a new diagnostic method that allows visual display of blood flow in the basal cerebral arteries. This method allows determination of and correction for the Doppler angle of insonation. Conventional transcranial Doppler sonography has no imaging component and assumes a 0‐degree Doppler angle for the calculation of flow velocities. The magnitude of the angle of insonation and the effect on flow velocity estimates have not been clearly defined. In order to evaluate the angle of insonation and the effect of angle correction on velocity readings, 50 patients referred for evaluation of cerebrovascular disease were studied. The mean age was 45 years (range, 24‐62 yr). All were examined with conventional transcranial Doppler and transcranial duplex color‐flow imaging. Specific vessels of the circle of Willis were identified by location, course, and direction of flow on color‐flow images and by depth, direction of flow, and transducer orientation with conventional Doppler sonography. Visually controlled measurements of the Doppler angle of insonation were made by color‐flow imaging. The data show that the mean angle of insonation was 33 degrees (± 15) in the middle cerebral artery, 35 degrees (± 17) in the anterior cerebral artery, 45 degrees (± 18) in the posterior cerebral artery, and 15 degrees (± 14) in the basilar artery. Angle‐corrected peak systolic flow velocities were higher in all vessel segments (middle cerebral = 15%, anterior cerebral = 18%, posterior cerebral = 30%, and basilar = 3%), compared to uncorrected velocity readings by conventional Doppler sonography. Colorflow imaging facilitates determination of the angle of insonation and angle correction of flow velocity estimates. These data suggest that the angle of insonation is greater than previously appreciated. Angle correction yielded higher average flow velocities in all vessels. The clinical importance of these higher, angle‐corrected velocities is not known.

ISSN:1051-2284    

DOI:10.1111/jon19944277

出版商:Wiley    

年代:2016

数据来源: WILEY

ISSN:1051-2284    

DOI:10.1111/jon19944281

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Brain computed tomography and a structured behavioral assessment provided a better correlation than did quantitative electroencephalography to the presence of mild stroke or transient ischemic attacks in 21 patients. When electroencephalography did not correlate well, it tended to localize too laterally or miss deep lesions. Computed tomography did not identify 2 lesions when done early after disease onset. No test was uniformly more sensitive or accurate than others. They may complement each other.

ISSN:1051-2284    

DOI:10.1111/jon19944282

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Brainstem involvement byToxoplasma gondiiis probably more common than other opportunistic infections, although it has not received adequate attention. Identification of toxoplasmosis is essential, as this condition responds to treatment with a significant increase in life expectancy. During the past 4 years, 366 AIDS patients with central nervous system toxoplasmosis diagnosed by biopsy or improvement following empirical treatment were evaluated. Among them, 8 (7 men, 1 woman; aged 25‐55 yr) presented with signs of brainstem dysfunction. Six patients presented with an oculomotor nerve palsy and contralateral hemiplegia; 1 had an additional ipsilateral rubral tremor. The seventh patient had complete external ophthalmoplegia and the eighth had Parinaud's syndrome. Computed tomography revealed enhancing lesions in the brainstem of all patients. Seven responded to treatment with pyrimethamine and sulfadiazine.

ISSN:1051-2284    

DOI:10.1111/jon19944285

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

To elucidate the evolution of crossed cerebellar diaschisis, cerebral oxygen metabolism was measured repeatedly by positron emission tomography (PET) in 35 consecutive patients with unilateral cerebral infarction within the territory of middle cerebral artery. The crossed cerebellar diaschisis was defined as significant when the laterality ratio of cerebral oxygen metabolism between the left and right cerebellar hemispheres exceeded the control range (mean ± 2 standard deviations) as derived from 27 age‐matched normal volunteers. Significant crossed cerebellar diaschisis was observed in 31 patients (89%) on the initial PET studies. Of these 31 patients, 23 with infarcts involving the frontal sensorimotor cortex persistently had crossed cerebellar diaschisis up to 5 years after onset, whereas the diaschisis disappeared in 8 patients with smaller infarcts mainly in the frontal or parietal lobe without recovery of oxygen metabolism in the infarcted areas. These present results suggest that crossed cerebellar diaschisis can exist persistently even in the late stage in those having a lesion involving the cortical pontine‐cerebellar pathways.

ISSN:1051-2284    

DOI:10.1111/jon19944291

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Motor cortex activity was localized with positron emission tomography (PET) in 4 patients with large arteriovenous malformations adjacent to or undercutting the left primary motor cortex. Relative cerebral blood flow responses were measured during execution of a visually guided motor tracking task performed with the right index finger, hand, great toe, tongue, or eyes alone (control) and mapped onto each patient's corresponding magnetic resonance imaging (MRI) scan. The relative cerebral blood flow responses in the contralateral precentral gyrus, adjacent to each arteriovenous malformation, demonstrated a normal somatotopic distribution, similar to that in a control population. In the 3 patients with preserved motor function, responses were also present in the ipsilateral primary motor cortex, bilateral supplementary motor area, and ipsilateral anterior cerebellum, similar in location to those of a control population. In the fourth patient with a hemiparesis, responses were attenuated in the primary motor cortex, increased in the supplementary motor area, and absent in the cerebellum. The results demonstrate that PET cerebral blood flow mapping can localize motor cortex despite the presence of significant blood flow abnormalities in adjacent arteriovenous malformations. The method, particularly when combined with MRI, may be used in the planning of surgical, radiation, or embolization therapy.

ISSN:1051-2284    

DOI:10.1111/jon19944297

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

This first known positron emission tomography report on metabolic changes in acute herpes simplex virus (HSV‐1) encephalitis demonstrates focal hypermetabolism in areas of cerebral cortex adjacent to actively inflamed hippocampus acutely infected with HSV‐1 . When neuropsychiatric symptoms recurred in a previously healthy 61‐year‐old patient 1 month after recovering from acute HSV‐1 encephalitis, repeat positron emission tomography with fluorodeoxyglucose was helpful in ruling out recurrent active infection by showing marked hypometabolism throughout the previously infected temporal lobe.

ISSN:1051-2284    

DOI:10.1111/jon199442104

出版商:Wiley    

年代:2016

数据来源: WILEY

摘要:

Marchiafava‐Bignami disease is a rare demyelinating disease involving the corpus callosum and other central white matter tracts. In the patient described here, the disease produced extensive demyelination of the corpus callosum and deep cerebral white matter. This widespread demyelination, confirmed pathologically, was associated with a fulminant fatal course. The magnetic resonance imaging appearance is quite suggestive of Marchiafava‐Bignami disease and plays an important role in the premortem diagnosis.

ISSN:1051-2284    

DOI:10.1111/jon199442106

出版商:Wiley    

年代:2016

数据来源: WILEY