The extensive development of basal moyamoya vessels is a sign of severe hemodynamic impairment in adult patients with ischemic moyamoya disease. The results may not apply to adults with hemorrhagic onset.
Background: Subcortical ischemic vascular dementia (SVD) caused by small-artery disease is a major cause of dementia. It still remains unclear, however, whether SVD may present with localized regional cerebral blood flow (rCBF) changes. We aimed to clarify the local rCBF changes associated with dementia in patients with early-stage SVD. Methods: The subjects consisted of 15 patients with early-stage SVD [Mini Mental State Examination (MMSE) score: 20 ± 3.5] without apparent brain atrophy (SVD group), 11 patients without dementia with white matter lesions (non-dementia-WML group) and 16 age-matched controls. All the subjects were right-handed and underwent brain perfusion single photon emission computed tomography (SPECT), magnetic resonance imaging and cognitive function testing. Statistical analysis of the differences in the SPECT rCBF was performed by SPM2. The degree of severity of the WMLs was evaluated based on the Scheltens rating scale. Results: The results of SPM analysis revealed that the rCBF in the SVD group was significantly decreased in the pulvinar nuclei of the thalamus of both sides as compared with that in the controls, and in the left pulvinar nucleus as compared with that in the non-dementia-WML group. On the other hand, SPM analysis revealed no significant reduction in rCBF in the non-dementia-WML group as compared with that in the controls. The WMLs in the left parietal region were severer in the SVD group than in the non-dementia-WML group. Conclusions: In patients with early-stage SVD without apparent brain atrophy, significant rCBF reduction in the bilateral pulvinar nuclei as compared with that in normal controls, and in the left pulvinar nucleus as compared with that in patients without dementia with WMLs was found.
Background and Purpose-Patients with carotid occlusive disease and stage 2 cerebral hemodynamic failure, characterized by an increased oxygen extraction fraction (OEF) as measured by positron emission tomography (PET) and otherwise known as misery perfusion, have a high risk of cerebral ischemia and subsequent stroke. In clinical practice, the detection of patients with misery perfusion through the use of widely available, noninvasive, and cost-effective modalities such as single-photon emission computed tomography (SPECT) is extremely important. Methods-We evaluated the relationships between the regional hemodynamic status of cerebral circulation, measured with split-dose [ 123 I] N-isopropyl-p-iodoamphetamine SPECT ( 123 I-IMP SPECT) and an acetazolamide challenge, and hemodynamic parameters, including OEF measured with PET, in 27 patients with both unilateral and bilateral carotid occlusive diseases. Results-A significant negative correlation was found between the SPECT-measured cerebrovascular reserve after acetazolamide administration and both the PET-measured OEF and cerebral blood volume. Neither the cerebrovascular reserve nor the cerebral blood flow index, when expressed as a SPECT-measured cerebrum-to-cerebellum ratio, was useful for detecting lesions with an elevated OEF. However, a combination of the cerebrovascular reserve and cerebral blood flow index showed high sensitivity, specificity, and positive predictive value for the detection of misery perfusion. Conclusions-Our study suggests that split-dose 123 I-IMP SPECT with an acetazolamide challenge could be useful for screening patients with misery perfusion in carotid occlusive diseases.
Because the CBF SPECT images of VaD patients showed a higher fractal dimension, these images were quantitatively more heterogeneous than those of age-matched controls. In the VaD group, cognitive function was shown to decline as the fractal dimension increased and images became more heterogeneous.
We compared neural activation detected by magnetoencephalography (MEG) during tactile presentation of words and non-words in a postlingually deaf-blind subject and six normal volunteers. The left postcentral gyrus, bilateral inferior frontal gyri, left posterior temporal lobe, right anterior temporal lobe, bilateral middle occipital gyri were activated when tactile words were presented to the right hand of the deaf-blind subject. This set of activated regions was not observed in the normal volunteers, although activation of several combinations of these regions was detected. Positron emission tomography confirmed the location of the MEG-activated areas in the deaf-blind subject. Our results demonstrated that the deaf-blind subject is heavily involved in interpreting tactile language by enhancing cortical activation of cognitive and semantic processing.
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