The University of Tokyo · Medicine
Professor Shigeki Yamada's research lab specializes in cerebrovascular and neurodegenerative disorders, with a focus on intracranial aneurysms, arteriovenous malformations (AVMs), and the pathophysiology of normal pressure hydrocephalus (iNPH). The lab investigates genetic factors in familial clustering of cerebrovascular diseases and identifies novel imaging biomarkers—such as z-Evans index and ventricular expansion parameters—for differentiating iNPH from Alzheimer’s disease. They also explore vascular risk factors, including transfusion history and small vessel disease, in relation to cerebral microbleeds and hemorrhagic stroke outcomes. Their work bridges clinical neurology, medical imaging, and genetics to improve early diagnosis and risk stratification in cerebrovascular diseases.
Figures are computed from collected data and may differ slightly.
Children, females, and patients with deep-seated AVMs had a threefold increased risk of rebleeding after an initial cerebral AVM. This increased risk was highest in the first year after the initial hemorrhage, and thereafter gradually decreased.
The CSF volume of the parietal convexity of <38 mL, upper-to-lower subarachnoid space ratio of <0.33, and the z-Evans Index of >0.42 were newly proposed useful indices for the idiopathic normal pressure hydrocephalus diagnosis, an alternative to the Evans Index.
A genome-wide scan in 29 Japanese families with a high degree of familial clustering revealed 1 suggestive linkage region on chromosome 17cen and 2 potentially interesting regions on chromosomes 19q13 and Xp22. These regions were consistent with previous findings in various populations.
History of blood transfusion was found to be an independent risk. The association between SAH and blood transfusion warranted further study.
The z-axial expansion of the lateral ventricle and compression of the brain just above the ventricle were the common findings in the parameters for differentiating idiopathic normal pressure hydrocephalus from Alzheimer disease.
High-grade PVH, high-grade DWMH, ICH, and atherosclerotic infarction were significantly independent predictors for cerebral microbleeds. In addition, we found that the grades of PVH and DWMH have a closer association with the number of cerebral microbleeds than age.
Idiopathic normal pressure hydrocephalus (iNPH) is considered an age-dependent chronic communicating hydrocephalus associated with cerebrospinal fluid (CSF) malabsorption; however, the aetiology of ventricular enlargement in iNPH has not yet been elucidated. There is accumulating evidence that support the hypothesis that various alterations in CSF dynamics contribute to ventricle dilatation in iNPH. This review focuses on CSF dynamics associated with ventriculomegaly and summarises the current l
It has been reported that percutaneous coronary intervention (PCI) is beneficial for coronary artery disease (CAD) among the general population. However, its effects in patients who are on hemodialysis (HD) remain unclear. A prospective cohort study was performed to clarify whether PCI has a therapeutic advantage over medical therapy among HD patients with CAD. A follow-up study to 5 yr was conducted among 259 HD patients with ischemic heart disease. Mean follow-up was 39 mo. Patients were divid
Patients with low-grade SAH caused by a ruptured MCA aneurysm had a low risk for the development of sNPH. In contrast, patients with high-grade SAH caused by a ruptured ACA aneurysm had a higher risk for sNPH. Endovascular coiling might confer a lower risk of developing sNPH than microsurgical clipping.
• The brain and CSF spaces were automatically segmented using an artificial intelligence-based application. • The total subarachnoid spaces increased linearly with aging, whereas the total ventricle volume was around 20 mL (< 2%) until the 60s and increased in ages above 60 years. • The cortical gray matter gradually decreases with aging, whereas the subcortical gray matter maintains its volume, and the cerebral white matter increases slightly until the 40s and begins to decrease from the 50s.
To clarify the pathogenesis of two different types of adult-onset normal-pressure hydrocephalus (NPH), we investigated cerebrospinal fluid distribution on the high-field three-dimensional MRI. The subarachnoid spaces in secondary NPH were smaller than those in the controls, whereas those in idiopathic NPH were of similar size to the controls. In idiopathic NPH, however, the basal cistern and Sylvian fissure were enlarged in concurrence with ventricular enlargement towards the z-direction, but th
An improvement of 5 seconds was a useful threshold of TUG time at the tap test for predicting a ≥10-second improvement 12 months after shunt surgery, rather than the percent improvement of TUG time.
The present study aimed to examine time-dependent change in cerebrospinal fluid distribution and various radiological indices for evaluating shunt effectiveness in patients with idiopathic normal pressure hydrocephalus (iNPH). This study included 54 patients with iNPH who underwent MRI before and after ventriculoperitoneal shunt surgery. The volume of the total ventricles and subarachnoid spaces decreased within 1 month after shunting. However, more than 1 year after shunting, the volume of the
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