Akira Ogawa

Oxygen extraction fraction (OEF) is a key predictor of stroke recurrence in patients with symptomatic major cerebral arterial occlusive disease. The purpose of the present study was to compare central benzodiazepine receptor binding potential (BRBP) and cerebral blood flow (CBF) images on SPECT with OEF images on PET in patients with chronic unilateral middle cerebral artery (MCA) or internal carotid artery (ICA) occlusive disease.

METHODS: OEF, CBF, and BRBP were assessed using (15)O ...

OBJECT: Intracranial hemorrhage associated with cerebral hyperperfusion syndrome (CHS) following carotid endarterectomy (CEA) or carotid artery stenting (CAS) is a rare but potentially devastating complication. In the present study the authors evaluated 4494 patients with carotid artery stenosis who had undergone CEA or CAS to clarify the clinicopathological features and outcomes of those with CHS and associated intracranial hemorrhage.

METHODS: Patients with postoperative CHS were ...

OBJECTIVE: Cerebral hyperperfusion after carotid endarterectomy (CEA) occurs in patients with preoperative impairments in cerebral hemodynamics. Signal intensity of the middle cerebral artery (MCA) on single-slab 3-dimensional time-of-flight magnetic resonance angiography (MRA) can assess hemodynamic impairment in the cerebral hemisphere. The purpose of the present study was to determine whether the signal intensity of the MCA on preoperative MRA could identify patients at risk for ...

OBJECT: The purpose of this study was to determine whether the preoperative measurement of acetazolamide-induced changes in cerebral blood flow (CBF), which is performed using single-photon emission computerized tomography (SPECT) scanning, can be used to identify patients at risk for hyperperfusion following carotid endarterectomy (CEA). In addition, the authors investigated whether monitoring of CBF with SPECT scanning after CEA can be used to identify patients at risk for ...

OBJECTIVE: Cerebral hyperperfusion syndrome after carotid endarterectomy (CEA) is a rare but potentially devastating complication. The purpose of the present study, which was not a randomized controlled trial but a case cohort study with historical control, was to determine whether pretreatment with a novel free radical scavenger, edaravone, could prevent occurrence of cerebral hyperperfusion after CEA.

METHODS: Fifty patients with ipsilateral internal carotid artery stenosis (>/=70%) ...

BACKGROUND: The effect of prasugrel in terms of the prevention of recurrence of ischaemic stroke is unknown. We investigated the non-inferiority of prasugrel to clopidogrel for prevention of ischaemic stroke, myocardial infarction, and death from other vascular causes in Japanese patients with non-cardioembolic stroke.

METHODS: In this phase 3 randomised, double-blind, non-inferiority trial, patients aged 20-74 years who had had a non-cardioembolic stroke in the previous 1-26 weeks were ...

BACKGROUND AND PURPOSE: Cerebral hyperperfusion syndrome is a rare but serious complication of carotid revascularization, including carotid endarterectomy (CEA) and carotid stent placement, which can occur in patients with preoperative impairments in cerebral hemodynamics. The purpose of this study was to determine whether preoperative cerebral blood volume (CBV) measured by perfusion-weighted MR imaging (PWI) could identify patients at risk for cerebral hyperperfusion after ...

BACKGROUND AND PURPOSE: Visualization of the peripheral arteries on single-slab 3D time-of-flight (TOF) MR angiography (MRA) can reflect blood flow velocity. The velocity in the middle cerebral artery (MCA) may correlate with cerebrovascular reactivity (CVR) to acetazolamide, which can be used to assess hemodynamic impairment. The goal of this study was to compare the signal intensity of the MCA on MRA versus CVR quantified by perfusion single-photon emission CT (SPECT).

MATERIALS AND ...

BACKGROUND AND PURPOSE: The Middle Cerebral Artery Embolism Local Fibrinolytic Intervention Trial (MELT) Japan was organized to determine the safety and clinical efficacy of intraarterial infusion of urokinase (UK) in patients with stroke within 6 hours of onset.

METHODS: Patients with ischemic stroke presenting within 6 hours of onset and displaying occlusions of the M1 or M2 portion of the middle cerebral artery on carotid angiography were randomized to the UK or control groups. ...

OBJECTIVE: Aneurysms at nonbranching sites in the supraclinoid internal carotid artery (ICA), known as blood blister-like aneurysms or ICA anterior or dorsal wall aneurysms, are not well understood. To clarify this clinical entity, 7408 patients with subarachnoid hemorrhage who were treated during a 5-year period were analyzed.

METHODS: Forty-eight patients had aneurysms that were intraoperatively confirmed to be located at a nonbranching site in the supraclinoid portion of the ICA. ...

BACKGROUND AND PURPOSE: The present study prospectively evaluated relationships among baseline characteristics, cerebral hemodynamics, and outcome of patients with symptomatic major cerebral artery occlusion, by quantitative measurement of cerebral blood flow using xenon-133 (133Xe) inhalation and single-photon emission computed tomography (SPECT).

METHODS: Regional cerebrovascular reactivity (rCVR) to acetazolamide was calculated at entry to the study using 133Xe SPECT. Seventy ...

Mental health is one of the most important issues facing disaster survivors. The purpose of this study is to determine the prevalence and correlates of mental health problems in survivors of the Great East Japan Earthquake and Tsunami at 6-11 months after the disaster. The questionnaire and notification were sent to the survivors in three municipalities in the Tohoku area of the Northern part of Honshu, Japan's largest island, between September 2011 and February 2012. Questionnaires were ...

PurposeThe aim of the present study was to determine whether preoperative cerebrovascular reactivity (CVR) to acetazolamide measured by quantitative brain perfusion single-photon emission computed tomography (SPECT) predicts development of cerebral ischemic lesions on postoperative diffusion-weighted magnetic resonance imaging (DWI) that are caused by microemboli during carotid endarterectomy (CEA).Materials and methodsOne hundred and fifty patients with ipsilateral internal carotid ...

OBJECTIVE: Therapeutic parent artery occlusion with or without revascularization is a useful surgical technique for the management of a giant aneurysm located in the intracavernous portion of the internal carotid artery (ICA). The purpose of the present study was to determine whether intraoperative cortical blood flow (CoBF) monitoring during surgical parent artery occlusion could identify patients who required bypass with a saphenous vein graft (high flow bypass).

METHODS: Eleven ...

PURPOSE: In patients with unilateral internal carotid or middle cerebral artery (ICA or MCA) occlusive disease, the degree of crossed cerebellar hypoperfusion that is evident within a few months after the onset of stroke may reflect cerebral metabolic rate of oxygen in the affected cerebral hemisphere relative to that in the contralateral cerebral hemisphere. The aim of the present study was to determine whether the ratio of blood flow asymmetry in the cerebellar hemisphere to blood flow ...