Hidehiko Endo

Iwate Medical University, Morioka-shi, Iwate-ken, Japan

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Publications (10)18.33 Total impact

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    ABSTRACT: Cerebrovascular reactivity (CVR) to acetazolamide is a key parameter in determining the severity of hemodynamic impairment in patients with major cerebral artery occlusive disease. Perfusion-weighted MRI (PW MRI) can measure the cerebral blood volume (CBV) as an indicator of hemodynamic impairment. CBV measured by PW MRI was compared with CVR measured by positron emission tomography (PET). Twelve normal subjects and 17 patients with major cerebral artery occlusive disease underwent PW MRI and PET. The images were coregistered with 3-dimensional spoiled gradient-recalled acquisition images. Quantitative PW MRI-CBV maps were generated using the indicator dilution method with arterial input function. One large cortical region of interest for each unilateral middle cerebral artery territory was determined on each image. PET-CVR was calculated by measuring cerebral blood flow before and after acetazolamide challenge. A significant negative correlation was observed between PW MRI-CBV and PET-CVR (r=-0.713; P<0.0001). PW MRI-CBV higher than the mean +2 SD obtained in normal subjects (15.2 mL/100 g) was defined as elevated and PET-CVR lower than the mean -2 SD obtained in normal subjects (15.1%) was defined as reduced. Assuming the PET-CVR as the true determinant of hemodynamic impairment, PW MRI-CBV provided 80.0% sensitivity and 91.7% specificity, with 80.0% positive predictive value for detecting patients with reduced CVR. The PW MRI-CBV method can simply and accurately identify patients with hemodynamic impairment without exposure to ionizing radiation.
    Stroke 03/2006; 37(2):388-92. · 6.16 Impact Factor
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    ABSTRACT: Some patients undergoing carotid endarterectomy (CEA) experience postoperative cognitive impairment. The purpose of the present case cohort study with historical control was to determine whether pretreatment with a novel free radical scavenger, edaravone, could prevent development of cognitive impairment after CEA. Fifty-five patients with ipsilateral internal carotid artery (ICA) stenosis (> or =70%) underwent CEA with administration of edaravone before ICA clamping. Neuropsychological testing was performed preoperatively and at the first postoperative month. Cerebral blood flow was also measured using single-photon emission computed tomography before and immediately after CEA and on the third postoperative day. Postoperative cognitive impairment was observed in only 1 (2%) patient, who exhibited postoperative cerebral hyperperfusion (cerebral blood flow increase > or =100% compared with preoperative values). Incidence of postoperative cognitive impairment in the control group (92 CEA patients without administration of edaravone) was significantly higher (12%) (P = .0298, control vs treatment group). Logistic regression analysis demonstrated that postoperative cerebral hyperperfusion and absence of pretreatment with edaravone were significant independent predictors of postoperative cognitive impairment. Pretreatment with edaravone can prevent development of cognitive impairment after CEA.
    Surgical Neurology 10/2005; 64(4):309-13; discussion 313-4. · 1.67 Impact Factor
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    ABSTRACT: A 47-year-old man presented with a ruptured vertebral artery dissecting aneurysm manifesting as subarachnoid hemorrhage followed by acute occlusion and early recanalization of the affected artery. Cerebral angiography 2 hours after the onset of the symptom showed pearl-and-string sign in the right vertebral artery. Serial angiography showed that the affected artery was occluded at 12 hours but was recanalized on the 4th day. The dissecting aneurysm was resected with side-to-side anastomosis between the bilateral posterior inferior cerebellar arteries. Postoperative cerebral angiography demonstrated disappearance of the lesion and patency of the right posterior inferior cerebellar artery via the anastomosis. Histological examination of the lesion showed hematoma between the media and adventitia, disrupting the internal elastica and intima. Acute occlusion and early recanalization of the affected artery may occur in ruptured vertebral artery dissecting aneurysms. Serial neurological and neuroradiological examinations are essential to decide the timing and method of treatment.
    Neurologia medico-chirurgica 09/2005; 45(8):400-3. · 0.49 Impact Factor
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    ABSTRACT: Cognitive impairment occurs in 20 to 30% of patients following carotid endarterectomy (CEA). The purpose of the present study was to determine whether postoperative cerebral hyperperfusion is associated with impairment of cognitive function in patients undergoing that procedure. Cerebral blood flow (CBF) was measured using single-photon emission computerized tomography scanning before and immediately after CEA and on the 3rd postoperative day in 92 patients with ipsilateral internal carotid artery stenosis of 70% or greater. Hyperperfusion post-CEA was defined as a 100% increase or greater in CBF compared with preoperative values. Neuropsychological testing was also performed preoperatively and at the 1-, 3-, and 6-month follow-up examinations. At the 1-month postoperative neuropsychological assessment, 11 patients (12%) displayed evidence of cognitive impairment. In addition, the incidence of postoperative cognitive impairment in patients with post-CEA hype perfusion (seven [58%] of 12 patients) was significantly higher than that in patients without post-CEA hyperperfusion (four [5%] of 80 patients; p < 0.0001). A logistic regression analysis demonstrated that post-CEA hyperperfusion was the only significant independent predictor of postoperative cognitive impairment. Of the seven patients in whom post-CEA hyperperfusion and cognitive impairment were identified 1 month postoperatively, four (including three patients with hyperperfusion syndrome) remained cognitively impaired at the 3- and 6-month follow-up examinations. Postoperative cerebral hyperperfusion is associated with impairment of cognitive function in patients undergoing CEA. Furthermore, the development of hyperperfusion syndrome is associated with the persistence of postoperative cognitive impairment.
    Journal of Neurosurgery 02/2005; 102(1):38-44. · 3.15 Impact Factor
  • Surgery for Cerebral Stroke 01/2005; 33(3):160-166.
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    ABSTRACT: 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. Fifty patients with ipsilateral internal carotid artery stenosis (>/=70%) underwent CEA with administration of edaravone before internal carotid artery clamping. Preoperative cerebral blood flow and cerebrovascular reactivity (CVR) to acetazolamide were assessed with single-photon emission computed tomography (SPECT). Cerebral blood flow also was measured immediately after CEA and on the 3rd postoperative day. Cerebral hyperperfusion (cerebral blood flow increase >/=100% compared with preoperative values) was revealed by SPECT performed immediately after CEA in only one patient (2%), who also exhibited reduced preoperative CVR. The incidence of post-CEA hyperperfusion as revealed by SPECT in the control group (51 CEA patients without administration of edaravone) was significantly higher (16%) (P = 0.0310, control versus treatment group). In addition, in a subgroup of patients with reduced preoperative CVR, the incidence of post-CEA hyperperfusion as revealed by SPECT in the edaravone group (7%) was significantly lower than that in the control group (67%) (P = 0.0029). Logistic regression analysis demonstrated that reduced preoperative CVR and absence of pretreatment with edaravone were significant independent predictors of post-CEA hyperperfusion as revealed by SPECT. Pretreatment with edaravone can prevent occurrence of cerebral hyperperfusion after CEA.
    Neurosurgery 12/2004; 55(5):1060-7. · 2.53 Impact Factor
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    ABSTRACT: Risk factors for intracerebral hemorrhage following carotid endarterectomy (CEA) include perioperative cerebral ischemia, postoperative cerebral hyperperfusion, and postoperative anticoagulation therapy, and at least 2 of these risk factors are typically present in the context of intracerebral hemorrhage (ICH). A 75-year-old man with severe bilateral cervical internal carotid artery stenosis and a minor stroke resulting in left motor weakness underwent a right CEA. The operation was uneventful, and the patient did not experience new neurologic deficits upon recovery from anesthesia. Brain single photon emission computed tomography (SPECT) obtained immediately after CEA showed a perfusion defect in the right parietal lobe and absence of cerebral hyperperfusion. A computed tomography (CT) scan showed no new abnormal findings. Aspirin therapy was instituted postoperatively. On the second postoperative day, the patient experienced abrupt worsening of left hemiparesis, and subsequent CT imaging demonstrated a hematoma in the right parietal lobe. Cerebral hyperperfusion was absent on repeat SPECT. Perioperative cerebral ischemia can result in intracerebral hemorrhage after CEA even in the absence of cerebral hyperperfusion and/or anticoagulation therapy. Further, cerebral perfusion imaging performed immediately after CEA is a useful modality for the identification of occult cerebral ischemia or hyperperfusion that may lead to intracerebral hemorrhage.
    Surgical Neurology 11/2004; 62(4):319-22; discussion 323. · 1.67 Impact Factor
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    ABSTRACT: Hyperperfusion syndrome is a rare but potentially devastating complication that can occur after carotid endarterectomy (CEA). The purpose of this study was to determine whether intraoperative transcranial regional cerebral oxygen saturation (rSO(2)) monitoring via near-infrared spectroscopy could be reliably used to identify patients at risk for post-CEA hyperperfusion. rSO(2) was intraoperatively monitored for 50 patients undergoing CEA for treatment of ipsilateral internal carotid artery stenosis (>/=70%). Cerebral blood flow (CBF) was also assessed, with single-photon emission computed tomography, before and immediately after CEA. Post-CEA hyperperfusion (CBF increase of >/=100%, compared with preoperative values) was observed for six patients. A significant linear correlation was observed between the rSO(2) increases immediately after declamping of the internal carotid artery and the CBF increases immediately after CEA (r(2) = 0.247, P = 0.0002). The sensitivity and specificity of the rSO(2) increases for detection of post-CEA hyperperfusion were 100 and 86.4%, respectively, with a cutoff point of 5%. A strong linear correlation was observed between the rSO(2) increases at the end of the procedure and the CBF increases immediately after CEA (r(2) = 0.822, P < 0.0001). Both the sensitivity and the specificity of the rSO(2) increases for detection of post-CEA hyperperfusion were 100% with a cutoff point of 10%. Hyperperfusion syndrome developed for one patient with post-CEA hyperperfusion, but intracerebral hemorrhage did not occur. Intraoperative rSO(2) monitoring can reliably identify patients at risk for hyperperfusion after CEA.
    Neurosurgery 08/2003; 53(2):309-14; discussion 314-5. · 2.53 Impact Factor
  • Nihon Kyukyu Igakukai Zasshi 01/2003; 14(11):745-747.
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    ABSTRACT: We encountered a case of aspergillus granuloma in the cavernous sinus originating in the left sphenoid sinus. The patient was a 56-year-old woman who complained of visual loss and cavernous sinus syndrome on the left side. Hematological data were within normal limits. Bone CT showed evidence of bone destruction in the roof of the left sphenoid sinus. MR images with gadolinium demonstrated an enhanced heterogeneous mass extending from the left sphenoid sinus to the cavernous sinus and the orbital apex. Angiography showed occlusion of the left internal carotid artery. Dexamethasone was administered intravenously every day, because the patient was diagnosed as having Tolosa-Hunt syndrome (THS). However, dexamethasone was not effective. We carried out a biopsy of the mass from the sphenoid sinus, and findings showed aspergillosis. On the 19th day after initiation of fluconazole treatment, the patient lapsed into unconsciousness and presented left hemiparesis. T2-weighted MR images showed high intensity areas in the pons and the thalamus. The patient died two days later. An autopsy revealed edema and many infarctions throughout the brain. The cavernous sinus had been replaced completely with aspergillus granuloma. Furthermore, numerous hyphae of aspergillus had adhered to the inside of the basilar artery, and caused occlusions of arteries around the brain. This case indicated the difficulty of diagnosis of THS and the hazard of over-application of steroids. In this paper, we describe the clinical and pathological behavior of aspergillosis in the cavernous sinus.
    No shinkei geka. Neurological surgery 05/2001; 29(4):325-9. · 0.13 Impact Factor