Osamu Takimoto

The University of Tokushima, Tokusima, Tokushima, Japan

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Publications (9)6.62 Total impact

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    ABSTRACT: The authors describe a novel technique involving the use of a gooseneck snare for microcatheterization of isolated sinus dural arteriovenous fistulas (DAVFs). In some patients the inferior petrosal and transverse-sigmoid sinuses, the route of transvenous embolization (TVE) for DAVF, are separated by several channels. Even if a guidewire can be passed over the occluded portion and the affected sinus can be accessed, one may not necessarily be able to insert a microcatheter. The authors report on three patients who underwent successful microcatheterization via a novel pull-up technique, which makes use of a gooseneck snare to perform TVE even in very difficult circumstances.
    No preview · Article · Jul 2006 · Journal of Neurosurgery
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    ABSTRACT: Oxidized low-density lipoprotein (OxLDL) plays a major role in atherosclerosis. We undertook the present study to clarify the relationship between plasma OxLDL and the ischemic volume. We used ELISA to determine plasma OxLDL levels, and performed diffusion- and perfusion-weighted MRI (DWI, PWI) to measure the ischemic volume in 44 ischemic stroke patients. Based on the location of the ischemic lesion, they were divided into three groups: Group I (GI, n = 21) had cortical lesions, Group II (GII, n = 17) had lesions in the basal ganglia or brain stem, and Group III (GIII, n = 6) had massive lesions that involved one entire hemisphere. In GI, but not GII and GIII, plasma OxLDL was significantly higher than in 19 age-matched controls (p < 0.01) and was significantly correlated with the initial ischemic volume visualized on DWI (p = 0.01), PWI (p < 0.01), and the DWI-PWI mismatch (p < 0.05). A persistent increase in plasma OxLDL was associated with enlargement of the ischemic lesion in the early phase after the insult. These findings suggest that elevated plasma OxLDL levels are associated with moderate ischemic damage in patients with cortical lesions (GI), but not those with massive hemispheric lesions (GIII), which may be irreversible. In addition, elevated plasma OxLDL may represent a predictor of enlargement of the ischemic lesion.
    No preview · Article · Jan 2005 · Neurological Research
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    ABSTRACT: Hereditary hemorrhagic telangiectasia (HHT) is easily overlooked in patients with central nervous system (CNS) lesions. Our clinical experience of three patients with CNS lesions associated with HHT stresses the importance of considering HHT. A 23-year-old male presented with consciousness disturbance and right hemiparesis. Emergency cerebral digital subtraction angiography revealed occlusion of the left middle cerebral artery and the left anterior cerebral artery. Pulmonary arteriography showed three pulmonary arteriovenous malformations (AVMs). A 62-year-old male presented with consciousness disturbance and sensory aphasia. Magnetic resonance imaging revealed a ring-enhanced lesion in the left temporal lobe which was removed by left frontotemporal craniotomy. The diagnosis was brain abscess. Chest computed tomography (CT) revealed two pulmonary AVMs. A 32-year-old female presented with progressive mild weakness in her left hand. Initial CT showed subcortical hemorrhage in the right frontal lobe. Cerebral angiography revealed no vascular malformations, but chest CT disclosed five pulmonary AVMs. All three patients had a family history of HHT. The possibility of HHT is important to consider in patients with cerebrovascular disease (CVD) or brain abscess to prevent complications, not only in the patients but also their blood relatives. Therefore, the medical and family history of patients with CVD or brain abscess should be investigated and HHT should be considered during the physical examination.
    No preview · Article · Oct 2003 · Neurologia medico-chirurgica
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    ABSTRACT: The differential diagnosis between brain abscesses and necrotic tumors such as glioblastomas is sometimes difficult to establish by conventional computed tomography and magnetic resonance imaging. Combined proton magnetic resonance spectroscopy (1H-MRS) and diffusion-weighted magnetic resonance imaging (DWI) were used to establish the preoperative diagnosis of brain abscess and glioblastoma. DWI visualized the brain abscess as a homogeneous hyperintense lesion and 1H-MRS revealed the presence of acetate, lactate, and amino acids and the absence of the normal brain components. DWI sometimes shows glioblastoma as a hyperintense lesion, but 1H-MRS reveals markedly increased lactate and decreased N-acetyl-aspartate. Combined DWI and 1H-MRS findings can distinguish brain abscess and glioblastoma.
    No preview · Article · Sep 2002 · Neurologia medico-chirurgica
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    ABSTRACT: The idea of deviation ratio topography (DRT), which we devised in 1986 to detect the dynamic electroencephalogram (EEG) variations, was based on the EEG constancy that the individual pattern of EEG topography shows almost the same pattern in the same condition. The DRT mapping is made of the logarithmic ratio between the control data (C) and measured data (M) that is recorded on the same electrode under different condition. The formula is as follows: logarithmic deviation ratio=log (M/C).With this DRT system, not only the changes in frequency bands but also the spatial and sequential changes of EEG activities are visually evaluated statistically.The clinical applications of DRT were as follows: (1) intraoperative monitoring, (2) EEG monitoring during physiological or mental tasks, (3) pharmaco-EEG monitoring and (4) the evaluation of EEG change after medication or operation.Unfortunately, this useful software of DRT had been written with the Signal BASIC language, which was equipped only in the machine of Signal Processor 7T18 and DP1100 (NEC Medical Systems). Therefore, the DRT system could be used only in the selected institute which had those machines. This time, we have composed the new software on a Windows-based DRT system.
    No preview · Article · Apr 2002 · International Congress Series
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    ABSTRACT: A 67-year-old woman presented with a right cervical mass which she had first noticed in May 1998. The hard elastic tumor was 4×3×3cm in size. A CT scan showed that the tumor was homogeneously enhanced. MR images (T1-WI) showed a homogenous isointense mass under the right carotid bifurcation. On B-mode ultrasonography with color flow Doppler, the tumor had a heterogeneous intensity and the margin was well demarcated. The right vagal nerve adjoined the tumor. The tumor was continuous with the cervical sympathetic nerve. Color flow Doppler showed pulsatile feeding arteries in the tumor. Conventional angiography showed that the tumor was fed by the right external carotid artery. We diagnosed the tumor as a neurinoma arising from the cervical sympathetic nerve. On Sept. 30, 1998, the cervical tumor was resected totally. On histological examination, the tumor was diagnosed as a neurinoma with components of Antoni B type. The patient showed Homer's symptoms after the operation.B-mode ultrasonography with color flow Doppler can provide anatomical details of tumors and be a very useful tool for evaluating cervical mass lesions.
    No preview · Article · Jan 1999 · Neurosonology

  • No preview · Article · Jan 1998 · Neurosonology
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    ABSTRACT: Transcranial Doppler sonography is frequently used to monitor cerebral blood flow velocities during open heart surgery. There was little information about Doppler findings in patients with congenital heart diseases and valvular heart diseases.This study included 12 women and six men, with a mean age of 40.6 years. Two patients had ventricular septal defect, four were diagnosed as having atrial septal defect, and one had both defects. Eleven patients underwent surgical replacement of heart valves. Two underwent aortic valve replacements and two underwent surgery on both the aortic and mitral valves. In seven patients, the mitral valve was replaced because of mitral regurgitation. The maximum, mean, and minimum flow velocities of the left middle cerebral artery (MCA) were measured intraoperatively before and after replacement. In the patients with aortic insufficiency and ventricular septal defect, the mean and diastolic flow velocities were markedly reduced on Doppler recordings before valvular replacement. In the patients with aortic insufficiency, a bisferious pulse was found on the Doppler spectra. In contrast, in the patients with mitral regurgitation and atrial septal defect, the Doppler waveforms showed normal findings preoperatively. In the patients with raised intracranial pressure, a high value of PI and low diastolic flow velocities were found on the TCD spectra. The same findings were sometimes seen in the patients with aortic insufficiency or ventricular septal defect. In patients with mitral insufficiency or atrial septal defect, the Doppler spectra showed no change on the TCD records postoperatively. Spiky contours were detected by Doppler in the patients with valvular heart disease secondary to subacute endocarditis.It is concluded that TCD could provide an approximation of changes in cerebral blood flow velocity in patients with valvular heart disease and ventricular septal defect.
    No preview · Article · Jan 1997 · Neurosonology
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    ABSTRACT: This study included 17 patients (5 men and 12 women) with a clinical diagnosis of moyamoya disease from conventional angiograms. Bilateral basal arteries were measured by the transtemporal approach with a 2-MHz pulsed Doppler instrument (TC-2 64B, EME) . Reliable TCD recordings were obtained in 28 out of 34 basal arteries (82.4%) . These TCD findings were classified into three patterns : 1) high-high pattern; the mean cerebral blood flow velocity (CBFV) was increased throughout the basal arteries by over 70 cm/s (7 arteries, 25.0%), 2) high-low pattern ; the mean CBFV was fastest (over 70 cm/s) at the ICA or proximal MCA, and the mean CBFV was markedly decreased distally (15 arteries, 53.6%), and 3) low-low pattern; the mean CBFV was less than 40 cm/s throughout the basal arteries (4 arteries, 15.4%) . The high-high pattern on TCD was seen predominantly in younger patients and those in the earlier stages of the disease. The high-low pattern was the most common one of CBFV as assessed by TCD in moyamoya patients. The low-low pattern on TCD was more common in the later stages following angiographic evaluation by Suzuki's criteria.The above patterns based on TCD findings show good correlation with the age of the patient and the clinical diagnosis at onset. TCD appears to be very useful for evaluation of patients with moyamoya disease.
    No preview · Article · Jan 1997 · Neurosonology

Publication Stats

65 Citations
6.62 Total Impact Points

Institutions

  • 2002-2006
    • The University of Tokushima
      • • Department of Neurosurgery
      • • School of Medicine
      Tokusima, Tokushima, Japan