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Biomedical subjects

A Inugami

Publications and source records attributed to A Inugami.

At least 55 records · Page 3Linked to original sources
PubMed1992

[Arterial clearance and cerebral uptake of Tc-99m ECD in patients with cerebrovascular disease compared with PET].

Technetium-99m ethyl cysteinate dimer (ECD) has recently developed for SPECT imaging in assessment of cerebral perfusion. We evaluated the arterial blood clearance and the regional brain uptake of Tc-99m ECD compared with the regional CBF measured by PET in patients with cerebrovascular disease. Nine patients with diagnosis of cerebral ischemic disorders (N = 7) and cerebral hemorrhage (N = 2) were studied. PET study was performed with HEADTOME IV by O-15 steady state inhalation method. Immediately after the PET study, 555-740 MBq (5-20 mCi) of Tc-99m ECD was injected intravenously. After injection arterial blood sampling was performed sequentially, and we separated lipophilic fraction from whole blood using ethyl acetate in two cases. The SPECT imaging with Tc-99m ECD (ECD-SPECT) was started 5 min (first imaging) and 60 min (second imaging) after the administration using a high resolution ring type SPECT system (HEADTOME II). Several ROIs were placed on practically the same anatomical location on both SPECT and PET images. Clearance of the tracer in arterial whole blood and lipophilic fraction was rapid. Concerning to the distribution pattern of ECD-SPECT images there was no differences between the 1st imaging and the 2nd imaging, although about 15% of diffuse decrease of Tc-99m ECD uptake was shown in the 2nd images. The brain distribution of ECD-SPECT was comparable to the pattern of CBF image by PET. The regional relative counts of ECD-SPECT corresponded closely to the CBF value by PET, but it was no linear correlation between brain uptake of ECD-SPECT and PET-CBF.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Magnetic resonance imaging of aneurysmal subarachnoid hemorrhage].

Magnetic resonance imaging of subarachnoid hemorrhage (SAH) due to aneurysm rupture was evaluated in relation to CT findings in nine patients. Six patients were studied within 3 days and the other three patients were studied 4 to 6 days from the ictus of SAH using a 0.5 Tesla superconducting unit. In all of the patients, hematoma in the subarachnoid space and ventricles was demonstrated by the proton density-weighted spin echo sequence, which showed that bloody cerebrospinal fluid (CSF) had a higher signal intensity than brain tissue or normal CSF. Magnetic resonance imaging was more sensitive in detecting SAH and more informative as to the site of the ruptured aneurysm than CT. Despite some limitations in applying it to patients with acute SAH, magnetic resonance imaging has clear advantages in the diagnosis of SAH.

Adult↗
PubMed1991

Multiple medullary venous malformations decreasing cerebral blood flow: case report.

A rare case of multiple medullary venous malformations in the right cerebral hemisphere is reported. The literature review yielded only one case of multiple medullary venous malformations. Computed tomography scan showed multiple calcified lesions with linear contrast enhancement representing abnormal dilated vessels and mild atrophic change of the right cerebral hemisphere. Single-photon emission computed tomography using N-isopropyl-p-(123I) iodoamphetamine demonstrated decreased cerebral blood flow in the right cerebral hemisphere.

Adult↗
PubMed1991

[The quantitative evaluation of myocardial blood flow and myocardial FDG uptake in the infarcted lesions with Q-wave and without Q-wave determined by O-15 water, FDG and PET].

Cardiac PET elicits an accurate relationship between myocardial blood flow (MBF) and tissue viability, which is evaluated by myocardial FDG uptake (MFU). To differentiate reversible tissue from necrotic tissue after the ischemic event, we from necrotic tissue after the ischemic event, we measured absolute MBF and MFU in patients with myocardial infarction. The MBF obtained by O-15 water and dynamic PET was accurately corrected by employing a tissue fraction (a) for the partial volume effect, including wall-motion effect. MFU was also corrected by using the tissue fraction. The subjects consisted of 5 patients with non-Q-wave infarction and 7 patients with Q-wave infarction. The regions of interest were selected from the infarcted area, each corresponding to regions with Q-wave or non-Q-wave. The MBFs in regions with Q wave (0.36 +/- 0.14 ml/min/g) were lower than those without Q wave (0.74 +/- 0.29 ml/min/g) (p less than 0.005). MFUs in regions without Q-wave (0.061 +/- 0.028) were higher than those with Q-wave (0.038 +/- 0.017) (p less than 0.05). The highest threshold of MBF in regions where Q-wave was detected was 0.55 ml/min/g. It is concluded that we will able to find the threshold of electrophysiological dysfunction in the infarcted region with this method.

Aged↗
PubMed1991

Clinical value of PET with 18F-fluorodeoxyglucose and L-methyl-11C-methionine for diagnosis of recurrent brain tumor and radiation injury.

We studied 15 patients clinically suspected to have recurrent brain tumor or radiation injury, using positron emission tomography (PET) with 18F-fluorodeoxyglucose (18FDG) and L-methyl-11C-methionine (11C-Met). PET with 11C-Met (Met-PET) clearly delineated the extent of recurrent brain tumor as focal areas of increased accumulation of 11C-Met, and was useful for early detection of recurrent brain tumor. PET with 18FDG (FDG-PET) showed focal 18FDG-hypermetabolism in one patient with malignant transformation of low grade glioma, and demonstrated its usefulness for evaluation of malignant transformation. 18FDG-hypometabolism was observed in all patients with radiation injury, but was also found in one patient with recurrent malignant brain tumor. 11C-Met uptake in 3 patients with radiation injury was similar to that of the normal cortical tissue. FDG-PET can be used to initially exclude recurrent brain tumor which is seen as 18FDG-hypermetabolism. The combined use of Met-PET in addition to FDG-PET can improve the accuracy of differentiation of recurrent brain tumor with 18FDG-hypometabolism from radiation injury.

Adolescent↗
PubMed1990

A case of medullary venous malformations with an arterial component coexisting with arteriovenous malformations.

We present a rare case of medullary venous malformations with an arterial component coexisting with two small arteriovenous malformations in the same area. The onset was abrupt with subcortical hematoma due to the rupture of one arteriovenous malformation in the frontal area. Single photon emission computed tomography using 99mTc-hexamethylpropyleneamine oxime showed a high-uptake area around the hematoma suggesting increased blood flow. Two types of vascular malformation coexisting in the same area support a theory of congenital malformation originating in intrauterine life.

Brain↗
PubMed1990

[The changes of cerebral blood flow and metabolism of normal brain tissue after surgery, radiation, and chemotherapy in brain tumor patients: evaluated by position emission tomography].

The changes of cerebral blood flow (CBF) and metabolism of normal brain tissue after surgery, radiation, and chemotherapy in brain tumor patients were measured by positron emission tomography (PET). The subjects consisted of 6 men and 3 women, and were from 11 to 62 years old. Those were four patients with glioblastomas, one patient with malignant oligodendroglioma, one patient with astrocytoma grade II, one patient with astrocytoma grade III, one patient with pontine glioma, one patient with pineal germinoma. Seven patients were operated and pathohistologically diagnosed. Two patients with pineal germinoma and pontine glioma were not operated and radiologically diagnosed. Of 7 operated patients, first PET was performed before operation in 3 patients, and from 10 to 16 days after operation in 4 patients. Following first PET, the patients were treated with irradiation (1 case), or with both irradiation and chemotherapy (8 cases). The total radiation dose for tumor was from 59 to 61 Gy distributed in a period of 6-8 weeks. Whole brain irradiation was performed up to 30 or 40 Gy, with a remaining dosimetry (20-30 Gy focused on the tumor field. Chemotherapy consisted of intravenous administration of ACNU and oral administration of FT-207. Second PET was performed 1 month after therapy (9 cases), and third PET was performed from 4 to 24 months after therapy (6 cases). Fourth PET was performed in 2 patients (22 and 35 months after therapy), and fifth PET was performed in one patient (35 months after therapy).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Comparison of Doppler velocimetry of the common carotid artery with cerebral blood flow measured by PET].

The cervical carotid Doppler velocity is determined by the cardiovascular function, hemodynamic characteristics of proximal vascular beds, the carotid artery, and the distal vascular beds, i.e., cerebral circulation. If the former three factors remain constant, cervical carotid Doppler velocimetry reflects the cerebral circulation. The purpose of this report is to study whether the cervical carotid Doppler velocimetry reflects cerebral circulation or not. Parameters measured by the common carotid Doppler velocimetry were compared with cerebral blood flow (CBF) in the internal carotid arterial distribution measured by positron emission tomography (PET) in 50 patients, aged from 33 to 72 years old (mean: 56.5 +/- 8.6). These subjects were 14 with cerebral infarction, 12 with no abnormality (normal volunteers), 5 with brain tumor, 2 with normal pressure hydrocephalus, 3 with spinocerebellar degeneration, and so on. CBF was measured by the 15O-gas steady state method or H2(15)O autoradiographic method using a HEADTOME III scanner. Subsequently, pulsed Doppler flow velocimetry of the common carotid artery was performed using a RT-3600 scanner which employed a 5-MHz transducer, and systolic velocity (SV), diastolic velocity (DV), mean velocity (MV), and pulsatility index (PI) were measured. Cerebral angiography was performed in every patient except for normal volunteers, and it demonstrated no evidence of stenoocclusive lesions in the cervical carotid artery. X-ray computed tomogram (CT) was also performed in all patients. We compared CBF in the internal carotid arterial distribution with SV, DV, MV, and PI.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Brain glucose metabolism in a patient with Creutzfeldt-Jakob disease measured by positron emission tomography].

Sequential measurements of local cerebral glucose metabolism were performed in a case with Creutzfeldt-Jakob disease. The diagnosis was based on the characteristic clinical symptoms and EEG. Cerebral glucose metabolism (CMRGlc) was measured by positron emission tomography (PET) and 18F-fluorodeoxyglucose. CMRGlc was decreased to about 45% of the normal value. At that time, X-ray CT revealed little brain atrophy. The decrease of CMRGlc was prominent in cerebral cortices, but the metabolic decrease was slight in striatal body, cerebellum, and brainstem. The motor cortex and occipital lobe showed relatively preserved metabolism among the cerebral cortices. Six months after the first PET measurement, X-ray CT showed marked brain atrophy. Decrease of cerebral glucose metabolism advanced furthermore. However, the progress of the decrease was relatively small in the basal ganglia, brainstem, and cerebellar nucleus. These findings differ from the findings that was known by pathological study. These results suggest that measurement of CMRGlc by PET is useful for the early detection and for understanding of the pathophysiology of this disease.

Brain↗
PubMed1990

[Compartment analysis of 123I-IMP brain SPECT].

To clarify the kinetics of N-isopropyl [123I]p-iodoamphetamine (IMP) in the brain, 2-compartment analysis was applied for brain SPECT with 57-minute dynamic scan in 9 subjects. The model consisted of blood component and brain tissue component. Two transfer rate constants were defined; k1 showed the rate from the blood to the brain tissue, and k2 was that of back diffusion. The late scan was performed 210 minutes after the tracer injection. Suitable k values best fitting to the dynamic data were determined for all regions of interest. Predicted regional cerebral activity at 210 minutes using 57-minute dynamic data was well agreed with measured activity. These showed the kinetics of IMP in the brain was well described by the 2-compartment model. The partition coefficient (k1/k2 ratio) was as large as about 35, and almost constant in the various brain structures including hypoperfused areas. These findings indicated that the initial IMP images reflected the reasonable CBF distribution, which gave relatively reliable CBF values even if using microsphere model.

Amphetamines↗
PubMed1990

[Quantitative evaluation of myocardial blood flow and myocardial fluoro-deoxyglucose uptake determined by PET before and after aorto-coronary bypass operation in patients with ischemic heart disease].

Absolute myocardial blood flow (MBF) and myocardial FDG uptake (MFU) in the fasting state were determined in 5 patients who underwent aorto-coronary bypass operation, using O-15 water, F-18 fluoro-deoxyglucose and dynamic PET before and after the operation. In the patent graft region, MBF was increased from 0.59 +/- 0.17 ml/min/g to 0.77 +/- 0.14 ml/min/g (p less than 0.05). Mean MBF was increased from 0.69 +/- 0.22 ml/min/g to 0.83 +/- 0.18 ml/min/g (p less than 0.05). MFU in the fasting state was significantly decreased in high MFU region compared with low MFU region (p less than 0.005). Quantitative evaluation of MBF and MFU before aorto-coronary bypass operation was quite useful to determine adequate indication of the operation.

Aged↗
PubMed1990

[Positron emission tomography in acute disseminated encephalomyelitis: a case report].

Sequential positron emission tomography (PET) and single photon emission tomography (SPECT) were performed in an 11-year-old girl who was clinically diagnosed as acute disseminated encephalomyelitis (ADEM). She had fever, stupor, loss of sight and left hemiparesis on admission to our hospital. X-ray CT (XCT) demonstrated a hypodense lesion in the right fronto-parietal white matter. In the 1st PET study, CBF and CMRO2 were reduced in both hemispheric white and gray matter, particularly in the right fronto-parietal lesion. The XCT abnormality was improved in the subsequent scan when the patient had improved except visual disturbance. When visual disturbance was worsened again, and a new hypodense lesion was appeared in the left frontal white matter on XCT, the 2nd PET study was performed. CBF and CMRO2 were recovered except the left frontal white and gray matter. SPECT study was also performed and the image was almost similar to CBF image of PET scan. The changes and distributions of CBF and CMRO2 were related to her symptoms and clinical course. Reduced CBF and CMRO2 of whole brain is thought to be characteristic of ADEM. From the experiences of this case, PET measurements is useful for the understanding of neuronal functional abnormalities of ADEM, and is more useful for the detection of recovery or relapsing process than XCT.

Acute Disease↗
PubMed1990

[Value of 11C-methionine and PET in the diagnosis of low grade gliomas].

Ten patients with low grade glioma were examined with positron emission tomography (PET) using 11C-methyl-L-methionine (11C-Met). In 4 cases, follow-up study was performed after radiation therapy. 11C-Met uptake index was calculated by sequential arterial blood sampling and PET image on 45 minutes after injection. The tumor was clearly seen in the images, and uptake index in the tumor lesion was higher than that in the normal cortex. The uptake of 11C-Met was observed in a recurrent lesion that was confirmed by operation. 11C-Met uptake indices were decreased in the tumor lesions after radiation therapy. From these results PET with 11C-Met is a useful clinical tool for diagnosis of low grade gliomas.

Adolescent↗
PubMed1989

[Vascular responses in cerebrovascular "Moyamoya" disease--evaluated by positron emission tomography].

We investigated cerebral blood flow and metabolism, and cerebral vascular response in 9 patients with cerebrovascular Moyamoya disease or unilateral Moyamoya phenomenon using positron emission tomography (PET). The subjects consisted of 5 men and 4 women, and were from 9 to 60 years old. Five patients had bilateral occlusion in the carotid fork with Moyamoya vessels (fulfilled the criteria of cerebrovascular Moyamoya disease), and four patients had unilateral Moyamoya phenomenon. The PET scanner used was the HEADTOME III, of which spatial resolution in clinical use was 10 mm full width at half-maximum (FWHM) in the image plane. Cerebral blood flow (CBF), cerebral metabolic rate of oxygen (CMRO2), cerebral oxygen extraction fraction (OEF), and cerebral blood volume (CBV) were measured in resting state by the 15O-labelled gases steady state method in every patient and 22 normal controls (17 men and 5 women, and from 26 to 64 years old). Consecutively cerebral vascular responses were measured by H215O autoradiographic method in resting state, hypercapnia, hypocapnia, and hypertension. Forced hypercapnia, hypocapnia, and hypertension were achieved by 7% CO2 inhalation, hyperventilation, and venous infusion of angiotensin II, respectively. CMRO2 of the whole brain was significantly lower in patients than in normal controls (p less than 0.05), and CBV of the lentiform nucleus significantly increased in patients (p less than 0.01). This reflected Moyamoya vessels in the basal ganglionic regions. In 3 of 5 patients with bilateral Moyamoya vessels, CBF and CMRO2 in the symptomatic cerebral hemisphere were lower than that in the nonsymptomatic hemisphere.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1988

Linearization correction of 99mTc-labeled hexamethyl-propylene amine oxime (HM-PAO) image in terms of regional CBF distribution: comparison to C15O2 inhalation steady-state method measured by positron emission tomography.

The radioisotope distribution following intravenous injection of 99mTc-labeled hexamethylpropyleneamine oxime (HM-PAO) in the brain was measured by single photon emission computed tomography (SPECT) and corrected for the nonlinearity caused by differences in net extraction. The "linearization" correction was based on a three compartment model, and it required a region of reference to normalize the SPECT image in terms of regional cerebral blood flow distribution. Two different regions of reference, the cerebellum and the whole brain, were tested. The uncorrected and corrected HM-PAO images were compared with cerebral blood flow (CBF) image measured by the C15O2 inhalation steady state method and positron emission tomography (PET). The relationship between uncorrected HM-PAO and PET-CBF showed a correlation coefficient of 0.85 but tended to saturate at high CBF values, whereas it was improved to 0.93 after the "linearization" correction. The whole-brain normalization worked just as well as normalization using the cerebellum. This study constitutes a validation of the "linearization" correction and it suggests that after linearization the HM-PAO image may be scaled to absolute CBF by employing a global hemispheric CBF value as measured by the nontomographic 133Xe clearance method.

Adult↗
PubMed1988

Oxygen extraction fraction at maximally vasodilated tissue in the ischemic brain estimated from the regional CO2 responsiveness measured by positron emission tomography.

The oxygen extraction fraction (OEF) at maximally vasodilated tissue in patients with chronic cerebrovascular disease was evaluated using positron emission tomography. The vascular responsiveness to changes in PaCO2 was measured by the H2(15)O autoradiographic method. It was correlated with the resting-state OEF, as estimated using the 15O steady-state method. The subjects comprised 15 patients with unilateral or bilateral occlusion and stenosis of the internal carotid artery or middle cerebral artery or moyamoya disease. In hypercapnia, the scattergram between the OEF and the vascular/responsiveness to changes in PaCO2 revealed a significant negative correlation in 11 of 19 studies on these patients, and the OEF at the zero cross point of the regression line with a vascular responsiveness of 0 was 0.53 +/- 0.08 (n = 11). This OEF in the resting state corresponds to exhaustion of the capacity for vasodilation. The vasodilatory capacity is discussed in relation to the lower limit of autoregulation.

Adolescent↗
PubMed1988

Early CT finding in cerebral infarction: obscuration of the lentiform nucleus.

Early computed tomographic (CT) findings (scans obtained within 6 hours of the onset of stroke) were retrospectively analyzed in 25 patients with embolic cerebral infarction of the middle cerebral artery or internal carotid artery distribution, including the lentiform nucleus, diagnosed on the basis of findings at sequential CT. CT scans were analyzed for the following: (a) an obscured outline or partial disappearance of the lentiform nucleus, (b) a slight decrease in tissue density, or (c) effacement of the cortical sulci. One or more of these findings was recognized in 23 of 25 patients (92%). The first finding was noted most frequently, and it appeared earliest. Obscuration of the lentiform nucleus was thought to be an important early sign of cerebral infarction, including the lentiform nucleus.

Aged↗