Kenji Yoshida

Iwate Medical University, Morioka, Iwate, Japan

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Publications (50)167.08 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Positron emission tomography (PET) with radiolabeled 2-nitroimidazoles directly detects hypoxic but viable tissue present in an acute ischemic area in the human brain. This study using PET with 1-(2-(18)F-fluoro-1-[hydroxymethyl]ethoxy) methyl-2-nitroimidazole ((18)F-FRP170) aimed to determine whether tissue with an abnormally elevated uptake of (18)F-FRP170 exists in human chronic cerebral ischemia because of unilateral atherosclerotic major cerebral artery steno-occlusive disease. (18)F-FRP170 PET was performed, and cerebral blood flow and metabolism were assessed using (15)O-gas PET in 20 healthy subjects and 52 patients. A region of interest (ROI) was automatically placed in 3 segments of the middle cerebral artery territory in both cerebral hemispheres with a 3-dimensional stereotaxic ROI template using SPM2, and each PET value was determined in each ROI. The ratio of values in the affected versus contralateral hemispheres was calculated for the (18)F-FRP170 PET image. A significant correlation was observed between oxygen extraction fraction and (18)F-FRP170 ratios (ρ=0.509; P<0.0001) in a total of 156 ROIs in 52 patients. The specificity and positive-predictive value for a combination of an elevated oxygen extraction fraction and a moderately reduced cerebral oxygen metabolism for detection of an abnormally elevated (18)F-FRP170 ratio (19 ROIs: 12%) were significantly greater than those for the individual categories (elevated oxygen extraction fraction, moderately reduced cerebral oxygen metabolism, or reduced cerebral blood flow). Tissues with abnormally elevated uptake of (18)F-FRP170 exist in human chronic cerebral ischemia characterized by a combination of misery perfusion and moderately reduced oxygen metabolism because of unilateral atherosclerotic major cerebral artery steno-occlusive disease. © 2015 American Heart Association, Inc.
    Stroke 04/2015; DOI:10.1161/STROKEAHA.114.008238 · 6.02 Impact Factor
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    ABSTRACT: The purpose of the present study was to determine whether preoperative measurement of cerebral blood flow (CBF) with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy (CEA). CBF at the resting state and cerebrovascular reactivity (CVR) to acetazolamide were quantitatively assessed using N-isopropyl-p-[(123)I]-iodoamphetamine (IMP)-autoradiography method with single-photon emission computed tomography (SPECT) before CEA in 500 patients with ipsilateral internal carotid artery stenosis (≥ 70%). CBF measurement using (123)I-IMP SPECT was also performed immediately and 3 days after CEA. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in the affected cerebral hemisphere using a three-dimensional stereotactic ROI template. Preoperative decreases in CBF at the resting state [95% confidence intervals (CIs), 0.855 to 0.967; P = 0.0023] and preoperative decreases in CVR to acetazolamide (95% CIs, 0.844 to 0.912; P < 0.0001) were significant independent predictors of post-CEA hyperperfusion. The area under the receiver operating characteristic curve for prediction of the development of post-CEA hyperperfusion was significantly greater for CVR to acetazolamide than for CBF at the resting state (difference between areas, 0.173; P < 0.0001). Sensitivity, specificity, and positive- and negative-predictive values for the prediction of the development of post-CEA hyperperfusion were significantly greater for CVR to acetazolamide than for CBF at the resting state (P < 0.05, respectively). The present study demonstrated that preoperative measurement of CBF with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of the development of post-CEA hyperperfusion.
    Neurologia medico-chirurgica 02/2015; 55(2). DOI:10.2176/nmc.oa.2014-0269 · 0.65 Impact Factor
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    ABSTRACT: Extracranial-intracranial arterial bypass surgery is rarely performed for recurrent or progressing stroke due to vertebrobasilar artery steno-occlusive disease. Non-enhanced 7.0-T magnetic resonance (MR) imaging reveals cerebral arteries more clearly than 3.0-T or less MR imaging. A 45-year-old man developed recurrent transient ischemic attacks due to hemodynamic ischemia caused by occlusion of bilateral vertebral arteries despite antiplatelet therapy. MR angiography with a 7.0-T imager demonstrated that each marginal tentorial artery ran along the tentorial edge and anastomosed with each posterior cerebral artery (PCA) as collateral circulation. Superficial temporal artery (STA)-superior cerebellar artery (SCA) or PCA bypass surgery was planned through a subtemporal approach. During surgery, the SCA was not visible when the tentorial edge was elevated. The tentorium was not cut, and the STA was anastomosed with the P2 segment of the PCA. Ischemic symptoms completely resolved after surgery. Preoperative 7.0-T MR imaging visualized the marginal tentorial artery as an unusual collateral pathway in a patient with symptomatic bilateral vertebral artery occlusion undergoing arterial bypass surgery.
    Surgical Neurology International 10/2014; 5:157. DOI:10.4103/2152-7806.143760 · 1.18 Impact Factor
  • Japanese Journal of Neurosurgery 01/2014; 23(5):429-433. DOI:10.7887/jcns.23.429
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    ABSTRACT: BACKGROUND:: Carotid endarterectomy (CEA) might improve cognitive function. Fractional anisotropy (FA) values in the cerebral white matter derived from diffusion tensor magnetic resonance imaging (DTI) correlate with cognitive function in patients with various central nervous system diseases. OBJECTIVE:: To use tract-based spatial statistics (TBSS) to determine whether postoperative changes of FA values in the cerebral white matter derived from DTI are associated with cognitive improvement after uncomplicated CEA. METHODS:: In 80 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), FA values in the cerebral white matter were derived from DTI before and 1 month after surgery and were analyzed using TBSS. Neuropsychological testing, consisting of the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale and the Rey-Osterreith Complex Figure test, was also performed preoperatively and after the first postoperative month. RESULTS:: Based on the neuropsychologic assessments, 11 (14%) patients were defined as having postoperatively improved cognition. The difference between the two mean FA values (postoperative values minus preoperative values) in the cerebral hemisphere ipsilateral to surgery was significantly associated with postoperative cognitive improvement (95% confidence intervals, 2.632-9.877; P=0.0083). White matter FA values in patients with postoperative cognitive improvement were significantly increased after surgery in the whole ipsilateral cerebral hemisphere, in the contralateral anterior cerebral artery territory, and in the watershed zone between the contralateral anterior and middle cerebral arteries. CONCLUSION:: Postoperative increase in cerebral white matter FA on DTI is associated with cognitive improvement after uncomplicated CEA.
    Neurosurgery 06/2013; DOI:10.1227/NEU.0000000000000013 · 3.03 Impact Factor
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    ABSTRACT: 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 asymmetry in the cerebral hemisphere on positron emission tomography (PET) and single photon emission computed tomography (SPECT) correlates with oxygen extraction fraction (OEF) asymmetry in the cerebral hemisphere on PET in patients with chronic unilateral ICA or MCA occlusive disease and whether this blood flow ratio on SPECT detects misery perfusion in the affected cerebral hemisphere in such patients. Methods Brain blood flow and OEF were assessed using 15O-PET and N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) SPECT, respectively. All images were anatomically standardized using SPM2. A region of interest (ROI) was automatically placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres using a three-dimensional stereotaxic ROI template, and affected-to-contralateral asymmetry in the MCA territory or contralateral-to-affected asymmetry in the cerebellar hemisphere was calculated. Sixty-three patients with reduced blood flow in the affected cerebral hemisphere on 123I-IMP SPECT were enrolled in this study. Results A significant correlation was observed between MCA ROI asymmetry of PET OEF and the ratio of cerebellar hemisphere asymmetry of blood flow to MCA ROI asymmetry of blood flow on PET (r = 0.381, p = 0.0019) or SPECT (r = 0.459, p = 0.0001). The correlation coefficient was higher when reanalyzed in a subgroup of 43 patients undergoing a PET study within 3 months after the last ischemic event (r = 0.541, p = 0.0001 for PET; r = 0.609, p < 0.0001 for SPECT). The blood flow ratio on brain perfusion SPECT in all patients provided 100 % sensitivity and 58 % specificity, with 43 % positive and 100 % negative predictive values for detecting abnormally elevated MCA ROI asymmetry of PET OEF. Conclusion The ratio of blood flow asymmetry in the cerebellar hemisphere to blood flow asymmetry in the cerebral hemisphere on PET and SPECT correlates with PET OEF asymmetry in the cerebral hemisphere, and this blood flow ratio on SPECT detects misery perfusion in the affected cerebral hemisphere.
    European Journal of Nuclear Medicine 06/2013; 40(10). DOI:10.1007/s00259-013-2463-2 · 4.53 Impact Factor
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    ABSTRACT: Objective and subjective assessments of changes in cognition after carotid endarterectomy (CEA) were compared between older patients (≥76 years old) and younger patients (<76 years old). Patients underwent subjective cognitive assessment by a neurosurgeon and the patient's next of kin, and neuropsychological testing (five parameters) before and after surgery. Of 37 older patients studied, 4 (11%), 28 (75%), and 5 (14%) patients were defined as having subjectively improved, unchanged, and impaired cognition, respectively, following surgery. Differences in test scores (postoperative test score - preoperative test score: Δ score) in all neuropsychological tests were significantly lower in the older patients than in the 213 younger patients. The Δ score was able to statistically differentiate older patients with subjectively improved, unchanged, and impaired cognition after surgery. Receiver operating characteristic analysis showed that the Δ score cut-off point for detecting subjective improvement (upper cut-off point) and impairment (lower cut-off point) in cognition after surgery in older patients was identical to the mean or the mean +0.5 standard deviation (SD) and the mean -1.5 SD or the mean -1 SD, respectively, of the control value obtained from normal subjects. The upper and lower cut-off points were lower and higher, respectively, than those in younger patients. In conclusion, although neuropsychological test scores reflect the subjective assessment of postoperative change in cognition in older patients, the optimal cut-off points for the test scores to detect subjective improvement and impairment in cognition after CEA are different in older patients compared with younger patients.
    Neurologia medico-chirurgica 01/2013; 53(6):353-359. DOI:10.2176/nmc.53.353 · 0.65 Impact Factor
  • Surgery for Cerebral Stroke 01/2013; 41(5):368-372. DOI:10.2335/scs.41.368
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    ABSTRACT: Background: Cerebral hyperperfusion after carotid endarterectomy (CEA), even when asymptomatic, often impairs cognitive function. However, conventional magnetic resonance (MR) imaging rarely demonstrates structural brain damage associated with postoperative cognitive impairment. MR diffusion tensor imaging (DTI) is potentially more sensitive for detection of white matter damage. Among the common parameters derived by DTI, fractional anisotropy (FA) is a marker of tract integrity, and mechanical disruption of axonal cylinders and loss of continuity of myelin sheaths may be responsible for reduced FA in white matter. The purpose of the present study was to determine whether postoperative cerebral white matter damage that can be detected by FA derived by DTI is associated with cerebral hyperperfusion after CEA and correlates with postoperative cognitive impairment. Methods: In 70 patients undergoing CEA for ipsilateral internal carotid artery stenosis (≥70%), cerebral blood flow (CBF) was measured using single-photon emission computed tomography (SPECT) before and immediately after CEA and on postoperative day 3. FA values in cerebral white matter were assessed using DTI before and 1 month after surgery. These values were normalized and analyzed using statistical parametric mapping 5. In each corresponding voxel in the pre- and postoperative normalized FA maps of each patient, a postoperative FA value minus a preoperative FA value was calculated, and a voxel with postoperatively reduced FA was defined based on data obtained from healthy volunteers. The number of voxels with postoperatively reduced FA was calculated and defined as the volume with postoperatively reduced FA. Neuropsychological testing, consisting of the Wechsler Adult Intelligence Scale Revised, the Wechsler Memory Scale and the Rey-Osterreith Complex Figure test, was also performed preoperatively and after the first postoperative month. Postoperative cognitive impairment on neuropsychological testing in each patient was defined based on data obtained from patients with asymptomatic unruptured cerebral aneurysms. Results: Post-CEA hyperperfusion on brain perfusion SPECT (CBF increase ≥100% compared with preoperative values) and postoperative cognitive impairment on neuropsychological testing were observed in 11 (16%) and 9 patients (13%), respectively. The volume with postoperatively reduced FA in cerebral white matter ipsilateral to surgery was significantly greater in patients with post-CEA hyperperfusion than in those without (p < 0.0001). This volume in cerebral white matter ipsilateral to surgery was also significantly associated with postoperative cognitive impairment (95% confidence interval, 1.559-8.853; p = 0.0085). Conclusions: Cerebral hyperperfusion after CEA results in postoperative cerebral white matter damage that correlates with postoperative cognitive impairment.
    Cerebrovascular Diseases 11/2012; 34(5-6):358-367. DOI:10.1159/000343505 · 3.70 Impact Factor
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    ABSTRACT: BACKGROUND: We report a case of an uncommon association of pituitary adenoma with neuronal choristoma that usually is diagnosed at initial surgery. CASE DESCRIPTION: A 50-year-old woman with acromegaly and bitemporal hemianopsia underwent removal of a pituitary adenoma via the transsphenoidal approach. Histologic examination of the first surgical specimen demonstrated only adenoma, which was eosinophilic and expressed growth hormone. Fourteen years later, bitemporal hemianopsia recurred, and magnetic resonance imaging revealed regrowth of the residual tumor. DISCUSSION: The patient underwent removal of the regrown tumor via the transsphenoidal approach. Histologic examination of the second surgical specimen revealed gangliocytoma and a small component of pituitary adenoma. CONCLUSIONS: The present case report supports the theory that pituitary adenoma with neuronal choristoma might represent the result of neuronal differentiation from pituitary adenoma.
    World Neurosurgery 06/2012; 80(3-4). DOI:10.1016/j.wneu.2012.06.031 · 2.42 Impact Factor
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    ABSTRACT: The aim of the present study was to determine whether central benzodiazepine receptor binding potential (BRBP)/cerebral blood flow (CBF) or a combination of CBF and cerebrovascular reactivity (CVR) to acetazolamide on single-photon emission computed tomography (SPECT) more accurately detects misery perfusion, indicating elevation of absolute value of oxygen extraction fraction (OEF) on positron emission tomography (PET), in patients with unilateral major cerebral artery occlusive diseases. In 84 patients, OEF, CBF, CVR to acetazolamide, and BRBP were assessed using ¹⁵O-PET and N-isopropyl-p-[¹²³I]-iodoamphetamine and [¹²³I]-iomazenil SPECT, respectively. A region of interest was automatically placed in the middle cerebral artery territory using a 3-dimensional stereotactic region of interest template. Sensitivity, specificity, and positive and negative predictive values for the affected side-to-contralateral side asymmetry on SPECT-BRBP/CBF to detect the abnormally elevated PET-OEF in the affected hemisphere were 100%, 86.4%, 66.7%, and 100%, respectively. Area under the receiver operating characteristic curve in detecting the abnormally elevated PET-OEF in the affected hemisphere did not differ between analysis of the combination of SPECT-CBF and SPECT-CVR in the affected hemisphere (0.89; 95% confidence interval, 0.80-0.94) and that of the affected side-to-contralateral side asymmetry on SPECT-BRBP/CBF (0.93; 95% confidence interval, 0.86-0.97). The combination of the 3 detected abnormally elevated PET-OEF with 97.0% specificity and 90.0% positive predictive value. The accuracy of central BRBP/CBF asymmetry on SPECT is equivalent to that of the combination of CBF and CVR to acetazolamide on SPECT for detecting misery perfusion in patients with unilateral major cerebral artery occlusive disease.
    Clinical nuclear medicine 03/2012; 37(3):235-40. DOI:10.1097/RLU.0b013e31823ea69f · 2.86 Impact Factor
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    ABSTRACT: The purpose of the present study was to determine whether preoperative cerebral blood flow (CBF) or cortical central benzodiazepine receptor binding potential as measured by brain perfusion or (123)I-iomazenil (IMZ) single-photon emission computed tomography (SPECT) imaging, respectively, can predict cognitive improvement after uncomplicated carotid endarterectomy (CEA). Neuropsychological testing was performed preoperatively and after 1 month postoperatively in 140 patients who underwent CEA for unilateral internal carotid artery (ICA) stenosis (≥ 70%). Brain perfusion SPECT using N-isopropyl-p-[(123)I]-iodoamphetamine and IMZ SPECT was also performed before surgery. SPECT data were analyzed using a 3-dimensional stereotaxic region-of-interest template. Fourteen patients (10%) showed improved cognitive function postoperatively. Logistic regression analysis demonstrated that, among the variables tested, low relative CBF in the cerebral hemisphere ipsilateral to surgery was significantly associated with postoperative cognitive improvement (95% confidence interval: 0.623-0.868; P = 0.0003). The combination of reduced relative CBF and moderately reduced relative uptake of IMZ identified development of postoperative cognitive improvement with 100.0% sensitivity, 84.9% specificity, a positive predictive value of 42.4%, and a negative predictive value of 100%. Further, in a subgroup of patients with reduced relative CBF and moderately reduced relative uptake of IMZ, the difference between these 2 values was significantly greater in patients with postoperative cognitive improvement than in those without (P < 0.0001). The combination of preoperative CBF and cortical central benzodiazepine receptor binding potential as determined by SPECT can predict cognitive improvement after CEA.
    Clinical nuclear medicine 02/2012; 37(2):128-33. DOI:10.1097/RLU.0b013e31823e9a9a · 2.86 Impact Factor
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    ABSTRACT: Objective and subjective assessments of postoperative improvement and impairment in cognition were prospectively compared in patients who underwent carotid endarterectomy (CEA). Each patient underwent subjective cognitive assessment by a neurosurgeon and the patient's next of kin, and neuropsychological testing consisting of five test scores within 7 days before surgery and between 1 and 2 months after surgery. Of 213 patients studied, 24 (11%), 166 (78%), and 23 (11%) patients were defined as having subjectively improved, unchanged, and impaired cognition, respectively, following surgery. In all neuropsychological tests, differences in test scores between the two tests (postoperative test score - preoperative test score) significantly differentiated patients with subjectively improved, unchanged, and impaired cognition after surgery. Receiver operating characteristic analysis showed that the cut-off point for the differences in neuropsychological test scores in detecting subjective improvement and impairment in cognition after surgery was identical to mean +2 standard deviations (SDs) and mean -2 SDs, respectively, of the control value obtained from normal subjects. Of 27 patients with differences in neuropsychological test scores more than the upper cut-off point and 26 patients with differences in neuropsychological test scores less than the lower cut-off point in one or more neuropsychological tests, 24 (89%) and 23 (88%) exhibited subjectively improved and impaired cognition, respectively, after surgery. The present study indicates that neuropsychological test scores reflect the subjective assessment of postoperative change in cognition, and can detect subjective improvement and impairment in cognition after CEA using the optimal cut-off points for the test scores.
    Neurologia medico-chirurgica 01/2012; 52(3):154-60. DOI:10.2176/nmc.52.154 · 0.65 Impact Factor
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    ABSTRACT: A 74-year-old man with a history of asymptomatic right internal carotid artery (ICA) occlusion experienced amaurosis fugax in the left eye. Angiography showed left cervical ICA stenosis in addition to right cervical ICA occlusion. The right anterior and middle cerebral artery (MCA) territories were perfused from the left ICA via the anterior communicating artery. Brain perfusion single-photon emission computed tomography revealed reduced cerebral blood flow and reduced cerebrovascular reactivity to acetazolamide only in the right cerebral hemisphere. The patient underwent left carotid endarterectomy (CEA). Transcranial Doppler monitoring showed microembolic signals in the left MCA during dissection of the left ICA, but intraoperative monitoring suggested absence of global hypoperfusion or ischemia in the bilateral cerebral hemispheres during left ICA clamping. Transient and slight motor weakness of the left upper extremity was noted on recovery from anesthesia. Diffusion-weighted magnetic resonance imaging demonstrated the development of new spotty ischemic lesions only in the right cerebral hemisphere. The present case suggests that intraoperative cerebral embolism causing postoperative neurological deficits can develop exclusively in the cerebral hemisphere contralateral to CEA if the hemisphere has preoperative hemodynamic impairment and collateral circulation via the anterior communicating artery from the ICA ipsilateral to CEA.
    Neurologia medico-chirurgica 01/2012; 52(3):161-4. DOI:10.2176/nmc.52.161 · 0.65 Impact Factor
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    ABSTRACT: Cerebral hyperperfusion following carotid endarterectomy (CEA) occurs in patients with preoperative impairments in cerebral hemodynamics. The aim of the present study was to determine whether late images/early images on preoperative brain (123)I-iomazenil (IMZ) single-photon emission computed tomography (SPECT), which correlate with oxygen extraction fraction images on positron emission tomography, could identify patients at risk for cerebral hyperperfusion following endarterectomy for unilateral cervical internal carotid artery (ICA) stenosis. In 80 patients, preoperative brain SPECT scans were initiated immediately after (early images) and 180 min after (late images) administration of (123)I-IMZ. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in both the cerebral hemispheres using a three-dimensional stereotaxic ROI template. Transcranial regional cerebral oxygen saturation (rSO(2)) was monitored using near-infrared spectroscope throughout carotid endarterectomy, and a patient was defined as having cerebral hyperperfusion when a ratio of rSO(2) at the end of the surgery to rSO(2) before ICA clamping was ≥ 1.1. Cerebral hyperperfusion was observed on intraoperative rSO(2) monitoring in eight patients (10%). Preoperative increase in affected side-to-contralateral side asymmetry on late/early (123)I-IMZ value was the only significant independent predictor of cerebral hyperperfusion (95% confidence interval [CI], 1.606 to 8.710; P = 0.0010). The preoperative late/early (123)I-IMZ asymmetry corresponded to an 88% sensitivity and 89% specificity, with 47% positive- and 98% negative-predictive values for the development of cerebral hyperperfusion. Preoperative late/early (123)I-IMZ images can identify patients at risk for cerebral hyperperfusion following endarterectomy for unilateral cervical ICA stenosis.
    American Journal of Nuclear Medicine and Molecular Imaging 01/2012; 2(1):77-87. · 3.25 Impact Factor
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    ABSTRACT: A 54-year-old man with a pulsatile mass on the right side of his neck suffered left hemiparesis due to cerebral infarction in the right cerebral hemisphere. Three-dimensional computed tomographic angiography revealed an aneurysm located at the origin of the right cervical internal carotid artery (ICA). On magnetic resonance (MR) imaging, the aneurysm included fresh and organized thrombi. Under intraoperative monitoring of transcranial Doppler (TCD), transcranial cerebral oxygen saturation (cSO2) and electroencephalogram (EEG), the aneurysm was removed and the right common carotid artery (CCA) and ICA were anastomosed using interposition graft of expanded polytetrafluoroethylene. Attempts were made to keep systolic blood pressure during surgery above a +10% increase. Microembolic signals developed on TCD during dissection of the aneurysm, and then the CCA was early clamped. Transcranial cSO2 on the right forehead and EEG showed no abnormal change throughout surgery. Postoperatively, MR imaging revealed two asymptomatic spotty ischemic lesions, and the patient had only hoarseness. The present case suggests that intentional hypertension and monitoring of TCD, transcranial cSO2 and EEG during surgery might minimize development of intraoperative ischemic events due to embolism from the surgical site and carotid clamping.
    Surgery for Cerebral Stroke 01/2012; 40(4):267-272. DOI:10.2335/scs.40.267
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    ABSTRACT: The aim of the present study was to determine whether early and late/early images on 123I-iomazenil (IMZ) single-photon emission computed tomography (SPECT) correlate with cerebral blood flow (CBF) images and oxygen extraction fraction (OEF) images on PET, respectively, in the cerebral cortex of patients with chronic unilateral middle cerebral artery or internal carotid artery occlusive disease. In 20 normal individuals and in 68 patients, CBF and OEF were assessed using 15O-PET, and brain SPECT scans were initiated immediately after (early images) and 180 min after (late images) the administration of 123I-IMZ. A region of interest was automatically placed in the middle cerebral artery territory in both cerebral hemispheres using a three-dimensional stereotaxic region of interest template, and the ratio of the value in the affected side to that in the contralateral side was calculated in each image. Among patients, a significant positive correlation was observed between PET-CBF ratios and the SPECT-early IMZ ratios (r=0.797, P<0.0001) as well as between the PET-OEF ratios and the SPECT-late/early IMZ ratios (r=0.679, P<0.0001). When an abnormally elevated PET-OEF ratio was defined as a value greater than the mean+2 SD obtained in normal participants, the SPECT-late/early IMZ ratios yielded 100% sensitivity and 93% specificity, with 76% positive-predictive and 100% negative-predictive values for detecting abnormally elevated PET-OEF ratios. Early and late/early images on 123I-IMZ SPECT correlate with CBF images and OEF images on PET, respectively, in the cerebral cortex of patients with chronic unilateral major cerebral artery occlusive disease.
    Nuclear Medicine Communications 11/2011; 33(2):171-8. DOI:10.1097/MNM.0b013e32834de94e · 1.37 Impact Factor
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    ABSTRACT: Risk factors for cerebrovascular complications developing during or after carotid endarterectomy (CEA) include preoperative impairments in cerebral hemodynamics, as detected by the demonstration of decreased cerebrovascular reactivity (CVR) to acetazolamide on brain perfusion SPECT. Central benzodiazepine receptor binding potential (CBRBP) and cerebral blood flow (CBF) images on SPECT provide high sensitivity and high specificity for detecting misery perfusion in patients with chronic unilateral major cerebral artery occlusive disease. The aim of the present study was to determine whether preoperative CBRBP/CBF images on SPECT could identify patients at risk for new cerebral ischemic events, including neurologic deficits and cerebral ischemic lesions on diffusion-weighted MRI, or cerebral hyperperfusion after CEA and to compare the predictive accuracy of CBRBP/CBF with that of CVR to acetazolamide on SPECT. CBF, CVR, and CBRBP were assessed using N-isopropyl-p-(123)I-iodoamphetamine ((123)I-IMP) and (123)I-iomazenil SPECT before CEA in 112 patients with unilateral internal carotid artery stenosis (≥ 70%). CBF measurement using (123)I-IMP SPECT was also performed immediately and 3 d after CEA. A region of interest was automatically placed in the middle cerebral artery territory in both cerebral hemispheres using a 3-dimensional stereotactic region-of-interest template. Diffusion-weighted MRI was performed within 3 d before and 24 h after surgery. A preoperative increase in the affected side-to-contralateral side asymmetry on CBRBP/CBF value was the only significant independent predictor of postoperative new cerebral ischemic events (95% confidence intervals [CI], 1.145-1.608; P = 0.0004) or post-CEA hyperperfusion (95% CI, 1.244-2.252; P = 0.0007). There was no difference in the ability to predict post-CEA hyperperfusion when comparing the area under the receiver-operating-characteristic curve of the affected side-to-contralateral side asymmetry on CBRBP/CBF and that of the CVR in the affected hemisphere. However, the former value (0.924; 95% CI, 0.854-0.972) was significantly greater than the latter value (0.782; 95% CI, 0.697-0.852) for the prediction of new postoperative cerebral ischemic events (P < 0.05). Preoperative CBRBP/CBF images on SPECT can more accurately identify patients at risk for cerebrovascular complications occurring during or after CEA when compared with preoperative CVR to acetazolamide.
    Journal of Nuclear Medicine 07/2011; 52(9):1400-7. DOI:10.2967/jnumed.111.087940 · 5.56 Impact Factor
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    ABSTRACT: The distribution of central benzodiazepine receptors in the human brain has been characterized by single-photon emission computed tomography (SPECT) using I-iomazenil, and it may dynamically change. We present the case of a 52-year-old man with left internal carotid artery occlusion, who underwent extracranial-intracranial arterial bypass surgery and exhibited postoperative improvement of cognition. Although preoperatively decreased cerebral blood flow and decreased cerebrovascular reactivity to acetazolamide on SPECT in the affected cerebral hemisphere resolved after surgery, preoperatively decreased cerebral metabolic rate of oxygen on positron emission tomography and decreased I-iomazenil uptake on SPECT in the affected frontal lobe also resolved after surgery.
    Clinical nuclear medicine 05/2011; 36(5):361-2. DOI:10.1097/RLU.0b013e31820aa17b · 2.86 Impact Factor
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    ABSTRACT: 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. OEF, CBF, and BRBP were assessed using (15)O PET and N-isopropyl-p-(123)I-iodoamphetamine and (123)I-iomazenil SPECT, respectively, in 20 healthy subjects and in 34 patients with unilateral MCA or ICA occlusive disease. All images were transformed into the standard brain size and shape by linear and nonlinear transformation using statistical parametric mapping for anatomic standardization. A region of interest (ROI) was automatically placed according to the arterial supply using a 3-dimensional stereotactic ROI template, and the ratio of the value in the affected side to that in the contralateral side was calculated in each image. Among patients with occlusive disease, a significant positive correlation was observed between PET OEF and SPECT BRBP/CBF ratios in 3 cerebral cortical regions (r = 0.851, P < 0.0001, for anterior cerebral artery [ACA] ROI; r = 0.807, P < 0.0001, for MCA ROI; and r = 0.774, P < 0.0001, for posterior cerebral artery [PCA] ROI), but there were no correlations between these 2 parameters in the basal ganglia or the cerebellum. When an abnormally elevated PET OEF ratio was defined as a value greater than the mean + 2 SDs obtained in healthy subjects, sensitivity and specificity were, respectively, 100% and 96% for the ACA ROI, 100% and 89% for the MCA ROI, and 100% and 93% for the PCA ROI for the SPECT BRBP/CBF ratio for detecting an abnormally elevated PET OEF ratio. BRBP/CBF images on SPECT correlate with OEF images on PET in a specific clinical setting-that is, in the cerebral cortex of patients with chronic unilateral MCA or ICA occlusive disease.
    Journal of Nuclear Medicine 03/2011; 52(4):511-8. DOI:10.2967/jnumed.110.084186 · 5.56 Impact Factor

Publication Stats

478 Citations
167.08 Total Impact Points

Institutions

  • 2002–2014
    • Iwate Medical University
      • • Department of Neurosurgery
      • • Cyclotron Research Center
      Morioka, Iwate, Japan
    • Yamaguchi University
      • Division of Neurosurgery
      Yamaguti, Yamaguchi, Japan
  • 2003
    • Hokkaido University
      Sapporo, Hokkaidō, Japan
  • 2002–2003
    • Osaka City University
      • Department of Neuroscience
      Ōsaka, Ōsaka, Japan