M oyaMoya disease (MMD) is a progressive stenoocclusive cerebrovascular disease characterized by collateral vascular networks that look like "a puff of smoke" (moyamoya vessels) at the base of the brain. 35,58 Various revascularization procedures have been shown to improve cerebral hemodynamics and decrease the risk of ischemic attack; however, hemodynamic compromises and bleeding-prone vasculopathy lead to postoperative neurological morbidity. In anesthesia management, hypocapnia during surgery induces critical decreases in cerebral blood flow. It is also well known that crying induces hyperventilation and stroke during the perioperative period in children. 45,51 Hemodynamic compromise is also aggravated by blood loss, decreased circulating volume, and low blood pressure. 38,53 Furthermore, recent studies have shown that postoperative hyperperfusion develops frequently after surgery. 11,60 A previous review suggested that direct and combined bypass for MMD provide better collateral circula- Object. Although combined direct and indirect anastomosis in patients with moyamoya disease immediately increases cerebral blood flow, the surgical procedure is more complex. Data pertinent to the postoperative complications associated with combined bypass are relatively scarce compared with those associated with indirect bypass. This study investigated the incidence and characteristics of postoperative stroke in combined bypass and compared them with those determined from a literature review to obtain data from a large population.Methods. A total of 358 revascularization procedures in 236 patients were retrospectively assessed by reviewing clinical charts and radiological data. PubMed was searched for published studies on surgical treatment to determine the incidence of postoperative complications in a larger population.Results. Seventeen instances of postoperative stroke were observed in 16 patients (4.7% per surgery, 95% CI 2.8%-7.5%). Postoperative stroke was more frequent (7.9% per surgery) in adults than in pediatric patients (1.7% per surgery, OR 4.07, 95% CI 1.12-14.7; p < 0.05). Acute progression of stenoocclusive changes were identified in the major cerebral arteries (anterior cerebral artery, n = 3; middle cerebral artery, n = 1; posterior cerebral artery, n = 2). The postoperative stroke rate was comparable with that (5.4%) determined from a literature search that included studies reporting more than 2000 direct/combined procedures. No differences in the stroke rates between the direct/combined and indirect procedures were found. In the literature review, direct/combined bypass was more often associated with excellent revascularization (angiographic opacification greater than two-thirds) than indirect bypass (p < 0.05).Conclusions. This experience of 358 consecutive procedures is one of the largest series for which the postoperative stoke rate for direct/combined bypass performed with a unified strategy has been reported. A systematic review confirmed that the postoperative stroke rate for the direct/combined pro...

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M oyamoya disease (MMD) is characterized by the presence of net-like collateral vessels at the brain base that are caused by progressive major cerebral artery occlusion. 1Executive function/attention and working memory, primarily mediated by the lateral prefrontal region, are impaired, suggesting that lateral prefrontal ischemia is responsible for neurocognitive dysfunction.2,3 A recent investigation revealed the association of neurocognitive dysfunction with reduced cerebral blood flow.3 Nevertheless, not all patients with neurocognitive dysfunction had cerebral infarction on conventional MRI. Thus, ischemia-induced subtle microstructural alterations, which are beyond the detectability of conventional MRI, underlie neurocognitive dysfunction in MMD.Subtle gray matter changes, not shown on conventional MRI, are successfully detected in many diseases, such as mild cognitive impairment and schizophrenia, through voxel-byvoxel comparison of gray matter density on 3-dimensional (3D) MRI.4,5 Diffusion tensor imaging (DTI) is reportedly highly sensitive to microstructural alterations in diffusion characteristics of white matter. [6][7][8][9] To the best of our knowledge, no reports have evaluated gray matter changes in MMD using 3D MRI. There are only few reports on DTI assessments of MMD white matter integrity.6-8 Nevertheless, these reports used a specified region-of-interest approach and evaluated only 2 major DTI indices, such as fractional anisotropy (FA) and mean diffusivity (MD). Voxel-based analysis of white matter can provide detailed topographical characteristics of white matter integrity, and tractography can show the integrity of the major white matter tracts that run in anatomic regions. Furthermore, additional information for characterizing chronic ischemia-induced white matter damage can be extracted by incorporating other major DTI indices, such as axial diffusivity (AD) and radial diffusivity (RD).Here, we investigated the brain's microstructure across different regions in adult MMD by a voxel-based analysis of gray and white matter and tractography, and evaluated the relationship of these microstructural alterations with hemodynamic compromise and neurocognitive dysfunction.Background and Purpose-The mechanisms underlying frontal lobe dysfunction in moyamoya disease (MMD) are unknown. We aimed to determine whether chronic ischemia induces subtle microstructural brain changes in adult MMD and evaluated the association of changes with neuropsychological performance. Methods-MRI, including 3-dimensional T1-weighted imaging and diffusion tensor imaging, was performed in 23 adult patients with MMD and 23 age-matched controls and gray matter density and major diffusion tensor imaging indices were compared between them; any alterations in the patients were tested for associations with age, ischemic symptoms, hemodynamic compromise, and neuropsychological performance. Results-Decrease in gray matter density, associated with hemodynamic compromise (P<0.05), was observed in the posterior cingulate cortex of pa...

Recent studies have indicated that bone marrow stromal cells (BMSC) may improve neurological function when transplanted into an animal model of CNS disorders, including cerebral infarct. However, there are few studies that evaluate the therapeutic benefits of intracerebral and intravenous BMSC transplantation for cerebral infarct. This study was aimed to clarify the favorable route of cell delivery for cerebral infarct in rats. The rats were subjected to permanent middle cerebral artery occlusion. The BMSC were labeled with near infrared (NIR)-emitting quantum dots and were transplanted stereotactically (1 × 10⁶ cells) or intravenously (3 × 10⁶ cells) at 7 days after the insult. Using in vivo NIR fluorescence imaging technique, the behaviors of BMSC were serially visualized during 4 weeks after transplantation. Motor function was also assessed. Immunohistochemistry was performed to evaluate the fate of the engrafted BMSC. Intracerebral, but not intravenous, transplantation of BMSC significantly enhanced functional recovery. In vivo NIR fluorescence imaging could clearly visualize their migration toward the cerebral infarct during 4 weeks after transplantation in the intracerebral group, but not in the intravenous, group. The BMSC were widely distributed in the ischemic brain and some of them expressed neural cell markers in the intracerebral group, but not in the intravenous group. These findings strongly suggest that intravenous administration of BMSC has limited effectiveness at clinically relevant timing and intracerebral administration should be chosen for patients with ischemic stroke, although further studies would be warranted to establish the treatment protocol.