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K Hashikawa

Publications and source records attributed to K Hashikawa.

At least 37 records · Page 2Linked to original sources
PubMed1999

Different neural substrates for Kanji and Kana writing: a PET study.

To investigate the neural substrate underlying the mechanisms of Kanji and Kana writing, we conducted a PET activation study during mental writing task in eight right-handed normal Japanese subjects. During scans subjects were required to mentally write a Kanji or three Kana letters with their right hand, for each stimulant word presented auditorily. The direct comparisons between Kanji writing and Kana writing revealed that the left posterior inferior temporal gyrus was activated in Kanji writing while the left angular gyrus was activated in Kana writing. In addition, more extensive areas were activated in Kanji writing compared with Kana writing. These results suggest that different respective neural substrates are involved in Kanji and Kana writing respectively.

Adolescent↗
PubMed1999

[A case of pure agraphia with a deficit of drawing].

We examined a drawing ability in a case with pure agraphia. The patient, having lesions in the left middle frontal gyrus and inferior parietal lobule, could not write in both dictation and spontaneous writing tasks, with the ability to copy letters being well spared. Correspondingly, he showed a deficit of spontaneous drawing, with the ability to copy complex figures being well spared. These findings suggest that he could have an impairment of retrieving visual image, not restricted to letter image. Although some previous cases with pure agraphia were attributed to an impairment of retrieving visual letter image, drawing ability which seemed to be related to retrieving visual image had not been investigated. In the present case, disability of both writing and drawing could be attributed to a common mechanism, that was an impairment of retrieving visual image. In addition, the patient did not show a significant difference between the performance on Kana writing and on Kanji writing. But it has been said that an impairment of retrieving visual letter image could be related to a deficit of Kanji writing more than of Kana writing. Then, it could be assumed that the mechanism of Kana writing involved not only the pathway depending on graphical motor pattern but one depending on visual image.

Agraphia↗
PubMed1999

Perception and conception: separate memory systems in the medial temporal lobe.

The purpose of the present study was to investigate, by using positron emission tomography, whether the functionally different types of information are subserved by different memory systems in human medial temporal lobe structures. Before explicit retrieval tests during scans, subjects studied words in perceptually and conceptually processed manners separately. It was found that different parts of the medial temporal lobe structures were involved in each of the different conditions. These results indicated that perceptually and conceptually processed types of information were subserved by at least two partially segregated memory systems in human medial temporal lobe structures.

Adult↗
PubMed1998

[A case of nodular fasciitis of the chest wall].

We present a case of nodular fasciitis of chest wall origin. A 62-year-old woman visited our hospital because of a rapidly growing hard tumor fixed to her right chest wall, measuring 7 x 8 cm in size. Although incisional biopsy specimen revealed that the tumor was suggestive of nodular fasciitis, the possibility that the tumor had a malignant component could not be excluded. Total excision of the mass with combined resection of 3rd, 4th, 5th ribs was performed to establish the histological diagnosis and treatment plan. We believe that the tumor proved to be malignant by excisional biopsy, should then undergo further excision with sufficient surgical margin. Nodular fasciitis may be misdiagnosed as a sarcoma due to its rich cellularity, mitotic activity and poorly circumscribed nature. Awareness of the histological features of nodular fasciitis, and its predilection for presenting as a rapidly growing mass, should decrease the likelihood of misdiagnosis and the attendant risk of over surgery.

Diagnosis, Differential↗
PubMed1998

SPECT findings in mitochondrial encephalomyopathy.

UNLABELLED: We investigated the alterations in regional cerebral blood flow (rCBF) in mitochondrial encephalomyopathy (MEM), using [123I]N-isopropyl-p-iodoamphetamine (IMP) or 99mTc-hexamethyl propyleneamine oxime SPECT in 10 MEM patients. METHODS: Four of the patients had MEM with lactic acidosis and strokelike episodes (MELAS), 2 had Kearns-Sayre syndrome (KSS), 1 had myoclonic epilepsy with ragged red fibers (MERRF) and 3 had cytochrome C oxidase deficiency (CCOD). Cerebral perfusion reserve was obtained from 6 patients (3 MELAS, 1 MERRF, 1 KSS, 1 CCOD) for a comparative analysis using the split-dose 123I-IMP SPECT method before and after the injection of acetazolamide. RESULTS: All patients with MELAS showed focal hypoperfusion in the parietal and/or occipital lobes. Follow-up studies (3 MELAS patients) revealed extension or improvement in the abnormal perfusion. The hypoperfused lesions were correlated with abnormal CT/MRI findings. Perfusion was normal in 1 MERRF, 2 KSS and 3 CCOD patients, whereas CT/MRI findings in 1 MERRF, 1 KSS and 1 CCOD patient were abnormal. The cerebral perfusion reserve in 3 MELAS patients was decreased significantly compared with that in patients with other types of MEM (MELAS 7.4%, other MEM 33.8%; p < 0.05). CONCLUSION: The rCBF was altered specifically in patients with MELAS, suggesting that brain perfusion SPECT will be useful in diagnosing and assessing such patients. The decreased cerebral perfusion reserve in patients with MELAS may represent an important feature of the pathogenesis of the strokelike episodes. The SPECT findings of patients with other types of MEM (MERRF, KSS and CCOD) were normal.

Adolescent↗
PubMed1998

Iodine-123-iomazenil and iodine-123-iodoamphetamine SPECT in major cerebral artery occlusive disease.

UNLABELLED: Iodine-123-iomazenil (IMZ) is a SPECT ligand for central-type benzodiazepine receptors, which are located only on neurons. We evaluated the feasibility of using IMZ SPECT for identifying neuronal damage in patients with the chronic phase of thrombotic cerebral ischemia. METHODS: We studied 15 patients with angiographically-confirmed unilateral severe occlusive lesions (occlusion or > 70% stenosis) in the carotid system. IMZ SPECT images obtained 180 min after injection of 167-222 MBq IMZ were analyzed. The regional cerebral blood flow and perfusion reserve were evaluated for comparison with IMZ SPECT findings, using the split-dose 123I-iodoamphetamine (IMP) SPECT method, coupled with intravenous injection of 1 g acetazolamide. On both SPECT images, the count ratio of the affected to the nonaffected whole MCA territory (A/NA ratio) and of the contralateral to the ipsilateral cerebellar cortex (C/I ratio) were determined. RESULTS: The A/NA ratio with IMZ was significantly higher than that with IMP (94.5% +/- 6.2% versus 91.4% +/- 6.6%, p < 0.005), although a significantly positive correlation was found between these two ratios (r = 0.854, p < 0.0001). The C/I ratio with IMP was decreased significantly in 5 patients compared with that in normal subjects, whereas the C/I ratio with IMZ was decreased in only 1 patient. There was no significant correlation between the A/NA ratio with IMZ and the perfusion reserve in the affected MCA territory. In 2 of 5 patients with a decreased A/NA ratio (<90%) with IMZ, decreased blood flow with preserved perfusion reserve and cerebral hemispheric atrophy were observed, which suggested the influence of neuronal loss due to chronic ischemia. CONCLUSION: These findings indicate that IMZ SPECT, which provides new information regarding neuronal damage after ischemic insult to the brain, is useful for evaluating thrombotic cerebral ischemia.

Amphetamines↗
PubMed1997

Comparison of iodine-123-iomazenil SPECT and technetium-99m-HMPAO-SPECT in Alzheimer's disease.

UNLABELLED: This study was designed to elucidate a central type of benzodiazepine (Bz) receptor distribution in patients with Alzheimer's disease using SPECT with [123I]iomazenil (IMZ). METHODS: Eight patients with probable Alzheimer's disease were studied. Benzodiazepine receptor imaging was performed 15 min (early) and 180 min (delayed) after intravenous administration of 167 MBq IMZ, sequentially, using hexamethylpropylene amine oxime (HMPAO) SPECT to evaluate regional cerebral perfusion. RESULTS: Early IMZ-SPECT depicted areas of reduced uptake in sites of decreased cerebral blood flow (CBF), but each area of decreased uptake was extended wider than the area of hypoperfusion. Delayed IMZ-SPECT images demonstrated a similar pattern of decreased area of CBF; the affected region in Bz receptor bindings, however, was clearer and broader compared with that in either HMPAO-SPECT or early IMZ-SPECT. In comparison with the uptakes for the normal cerebral hemisphere (ratio to the contralateral cerebellum) in patients with unilateral cerebral infarction as a control group (n = 4), the patients with Alzheimer's disease showed distinctive bilateral frontal or parietal defects (p < 0.05). CONCLUSION: Brain SPECT using IMZ may be more sensitive than CBF images in patients with Alzheimer's disease.

Alzheimer Disease↗
PubMed1997

Intra-individual differences between technetium-99m-HMPAO and technetium-99m-ECD in the normal medial temporal lobe.

UNLABELLED: Regional distributions of 99mTc-hexamethyl propyleneamine oxime (99mTc-HMPAO) and 99mTc-ethyl cysteinate dimer (99mTc-ECD) were compared in the normal brain. METHODS: Six paid, healthy volunteers (mean age 26 yr) had high-resolution neuroperfusion SPECT using both 99mTc-HMPAO and 99mTc-ECD on separate days. RESULTS: Regional distribution of the two tracers differed. Technetium-99m-HMPAO accumulated more in the thalamus, frontal lobe, temporal lobe and cerebellum than 99mTc-ECD, which accumulated more in the occipital and parietal lobes. There was a considerable difference in the accumulation of the two tracers in the medial temporal lobe. The percent accumulations of 99mTc-HMPAO and 99mTc-ECD in the medial temporal lobe compared with the mean global cerebral cortical accumulation were 93.9% +/- 2.4% and 83.1% +/- 4.1% (mean +/- s.d.), respectively. CONCLUSION: The results suggest that 99mTc-HMPAO and 99mTc-ECD require specific and separate criteria for diagnosing temporal lobe pathologies, such as dementia and temporal lobe epilepsy.

Adult↗
PubMed1997

Hemodynamic aspect of cerebral watershed infarction: assessment of perfusion reserve using iodine-123-iodoamphetamine SPECT.

UNLABELLED: The mechanism whereby watershed (WS) infarcts develop remains controversial, although a hemodynamic cause is usually assumed. The aim of this study was to investigate the relationship between the site of WS infarcts and the hemodynamic status of the cerebral circulation. METHODS: From among 96 consecutive patients with angiographically confirmed unilateral major cerebral artery obstruction (occlusion or > 70% stenosis), we investigated 29 patients with supratentorial WS infarcts on magnetic resonance imaging. The regional cerebral blood flow and perfusion reserve were quantified using the split-dose [123I]iodoamphetamine SPECT method, coupled with intravenous injection of 1 g of acetazolamide. Seven patients had a cortical WS infarct between the superficial branches of the anterior and middle cerebral arteries (MCAs) or between the middle and posterior cerebral arteries (Group C), and 22 had a deep WS infarct between the superficial branches and deep penetrating arteries of the MCA (Group D). Moreover, the patients in Group D were classified into two subgroups, i.e., Type A (n = 12), with lesions lying in the centrum semiovale above the level of the lateral ventricles, and Type B (n = 10), with lesions lying in the corona radiata adjacent to the lateral ventricles. RESULTS: Comparison of the Type of WS infarct with the clinical course of onset showed that sudden onset was more frequent in Group C than in Group D (p < 0.05). The perfusion reserve in the affected MCA territory in Group D (20.1% +/- 15.6%) was significantly lower than that in Group C (43.8% +/- 10.8%; p < 0.01) and that in 20 hemispheres (10 control subjects) without a major arterial lesion (54.7% +/- 16.4%; p < 0.01). Among the Group D patients, the patients with Type A infarcts showed a significantly lower perfusion reserve compared with those with Type B infarcts (p < 0.05). CONCLUSION: Patients with deep WS infarcts, especially Type A infarcts, showed severe hemodynamic impairment, whereas patients with cortical WS infarcts showed preserved perfusion reserve which appeared to be secondary to the embolism. The mechanism of development of WS infarcts is multifactorial, and distinguishing among these WS infarcts and from other types of infarct is important, because different pathogenic mechanisms require different therapeutic strategies.

Acetazolamide↗
PubMed1997

[Noninvasive measurement of a input function using beta camera for 15O-water injection method].

Dynamic images of positron distribution in artery were measured for noninvasive measurement of input function using beta camera. The beta camera was attached from the skin surface on the artery of arm during the PET measurement using the 15O-water injection method. Beta camera used had a field of view of 20 mm in diameter. After injection of 15O-water, time sequence images of the artery of 10 sec interval 15 frames were obtained. Regions of interest (ROIs) were set on the artery and on the adjacent area of the artery. By subtracting average counts in the latter ROI from in the former ROI, time activity curve similar to input function was noninvasively obtained.

Arteries↗
PubMed1996

[Evaluation of 123I-iomazenil SPECT in patients with ischemic cerebrovascular disease: comparative study with 123I-IMP SPECT].

Clinical evaluation of 123I-iomazenil, a new imaging agent for central-type benzodiazepine receptors with SPECT, was performed in patients with ischemic cerebrovascular disease. We investigated 15 patients with angiographically-proven severe occlusive lesions (occlusion or > 70% stenosis) in the unilateral carotid system. 123I-iomazenil SPECT images were compared with cerebral blood flow (CBF) images and the cerebral perfusion reserve, which were measured using the "split dose 123I-IMP SPECT method" before and after the intravenous injection of 1 g of acetazolamide. For the detection of ischemic lesions, CBF images were superior to 123I-iomazenil images based on visual analysis. Regarding the count ratio of the affected MCA territory to the non-affected (L/N), 123I-IMP was lower than 123I-iomazenil in most of the cases. In five patients showing "crossed cerebellar diaschisis" by 123I-IMP, asymmetry of the cerebellar accumulation was observed in only one patient with 123I-iomazenil, which was less prominent than with 123I-IMP. There was no significant correlation between the L/N ratio with 123I-iomazenil and the cerebral perfusion reserve in the affected MCA territory. However, in some cases showing a decreased L/N ratio (< 90%) with 123I-iomazenil, a decreased CBF with normal perfusion reserve and cerebral hemi-atrophy were observed with 123I-IMP and MRI, which suggested the influence of neuronal loss due to chronic ischemia. These results indicate that 123I-iomazenil SPECT, which provides new information regarding neuronal loss due to ischemic damage to the brain, is useful for the evaluation of ischemic cerebrovascular disease.

Adult↗
PubMed1995

Functional and anatomic evaluation of carotid atherothrombosis. A combined study of indium 111 platelet scintigraphy and B-mode ultrasonography.

We examined the relation between in vivo thrombogenicity and the morphology of carotid lesions to clarify the role of platelet deposition in carotid atherothrombosis. We evaluated 60 subjects (120 carotid bifurcations) who had at least one established risk factor for atherosclerosis by using indium 111 platelet scintigraphy and high-resolution B-mode ultrasonography. We evaluated platelet accumulation in the carotid arterial wall by means of a dual-tracer method that used In 111-labeled platelets and technetium 99m-labeled human serum albumin. The tracer accumulation was assessed both visually and semiquantitatively by using the platelet accumulation index, ie, the ratio of radioactivity of the amount of In 111-labeled platelets deposited on the vascular wall to the amount of radioactivity in labeled platelets circulating in the blood pool. The morphology of the carotid lesions was analyzed with B-mode ultrasonography in terms of the presence of ulceration, the maximum percent stenosis, the echogenicity of plaque, and the plaque score, which indicates the severity of systemic atherosclerosis. Platelet accumulation increased with increase in plaque score (P < .01), and the magnitude of platelet accumulation was significantly greater in lesions with ulceration than in those without (P < .05). The platelet accumulation index in vessels with plaque showed a very weak but significant correlation with maximum percent stenosis (r = .28, P < .05) and a stronger correlation with the unilateral plaque score (r = .42, P < .0001). Analysis of the echogenicity of plaque showed that heterogeneous plaque had a high frequency of accumulating platelets. Platelet accumulation was related to the surface characteristics and severity of carotid lesions, especially in the presence of ulceration.

Arteriosclerosis↗
PubMed1995

Three-dimensional display of surface cortical perfusion by SPECT: application in assessing Alzheimer's disease.

UNLABELLED: To better understand cortical perfusion, we developed a method for a three-dimensional display technique with 99mTc-hexamethylpropyleneamine oxime (HMPAO) SPECT. METHODS: Twelve patients with higher cortical dysfunction due to Alzheimer's disease and 18 age-matched controls were examined. Data acquisition was performed after intravenous injection of 740 MBq of 99mTc-HMPAO. After reconstructing the transaxial images, the three-dimensional images were obtained by modified volume rendering, where the surfaces were displayed in the corresponding colors as the maximum cortical value within a depth of 2 cm. RESULTS: In the control studies, almost all surface cortices were over 60% of the maximum cerebellar value. In Alzheimer's disease patients, areas of perfusion below 60% were detected in the temporo-parietal lesions and frontal lobe lesions in 6 of 12. These findings correlated with the neurological dysfunction. CONCLUSION: This method provides realistic three-dimensional information about surface cortical perfusion, which was found to be useful in clinical investigations of higher cortical dysfunction due to degenerative or cerebrovascular diseases.

Alzheimer Disease↗
PubMed1995

Super-early iodine-123-iodoamphetamine SPECT imaging of human primary motor cortex.

UNLABELLED: This study was designed to visualize the motor function area related to finger movements in normal human brain using super-early (first 640 sec of acquisition) [123l]iodoamphetamine ([123I]IMP) SPECT. METHODS: Seven healthy male volunteers performed paired, isolated baseline and task sessions. The task was a right thumb-to-fingers opposition task, which was loaded for the initial 11 min of the session. A high-performance, four-head SPECT camera was used. At each session, administration of 222 MBq [123I]IMP was followed by 16 serial 160-sec dynamic SPECT acquisitions. To obtain matched brain anatomical images, MRI was also performed using the same slice formation as in the SPECT study. After image reconstruction, ROIs were set on bilateral sensorimotor hand areas (SMHA), the supplementary motor area (SMA), the frontal, temporal and occipital lobes and the cerebellar hemispheres. The percent increase of ROI activity (%INC) in the task session compared with that in the baseline session was calculated in each ROI after normalization to the global brain radioactivity. RESULTS: There was significant activation of the left SMHA by the task, the amplitude of which was maximal in the initial phase of dynamic images (the super-early phase). This area was located in the left peri-central area identified on the analogous slice in the MR image. The left SMHA showed gradual and statistically significant decrease of %INC during the three phases. CONCLUSION: Super-early [123I]IMP may be used to identify the primary motor cortex and to evaluate its function in some pathological conditions.

Adult↗