Biomedical subjects

I Odano

Publications and source records attributed to I Odano.

At least 37 records · Page 2Linked to original sources

PubMed1995

Frequent TIA in the territory fed by the anastomosed STA after combined therapeutic ICA occlusion and extracranial-intracranial bypass: case report.

Frequent transient ischaemic attacks (TIAs) in the territory fed by the anastomosed superficial temporal artery (STA) after combined therapeutic internal carotid artery (ICA) occlusion and extracranial-intracranial bypass is described in a 52-year-old woman with a giant aneurysm in the supraclinoid portion of the left ICA showing impairment of visual acuity in the left eye and right upper quadrantanopia. After the balloon test occlusion of the left ICA which was tolerated, the left STA-middle cerebral artery anastomosis was performed and occlusion of the left ICA using detachable balloons was carried out a day later. TIAs corresponding to the territory fed by the anastomosed STA occurred nine times two to four days and five times eight to nine days after the ICA occlusion without new infarction on computed tomography (CT) scan. Single-photon emission computed tomography showed no hypoperfusion immediately after the initial TIA. CT scan revealed thrombosis of half of the aneurysm a day after the ICA occlusion. The patient developed the same TIA as previously by compression of the left anastomosed STA at the time of follow-up angiography which was carried out eight days after the occlusion. Although heparin was continuously administered after the ICA occlusion for two days, the initial TIA occurred during heparinization. Anticoagulation seemed to be inadequate judging from activated coagulation time and incomplete thrombosis of the aneurysm occurred during heparinization. It is likely that the TIAs are caused by embolism via the STA, which is a rare ischaemic complication.

Anastomosis, Surgical↗

PubMed1995

Evaluation of cerebral blood flow in patients with idiopathic orthostatic hypotension using Tc-99m HMPAO brain SPECT during postural testing.

To determine whether regional cerebral blood flow (rCBF) would change on standing in patients with idiopathic orthostatic hypotension (IOH), Tc-99m HMPAO SPECT studies were performed during postural testing in five patients with IOH. After 10 minutes of quiet rest on a bed, the patients arose quickly and, at the same time, the radiotracer was injected intravenously. SPECT data were obtained with a ring-type SPECT scanner. Another dose of Tc-99m HMPAO was injected with the subjects in the supine position, and SPECT was performed again. Image subtraction was used to evaluate the change in rCBF caused by postural testing. In all patients, the authors observed a decrease of rCBF ni the frontal cortex and basal ganglia. This preliminary study suggests that changes in rCBF occur in patients with IOH on standing, and Tc-99m HMPAO SPECT performed during postural testing may have an important role in evaluating these changes.

Brain↗

PubMed1995

A potential use of a 123I-labelled benzodiazepine receptor antagonist as a predictor of neuronal cell viability: comparisons with 14C-labelled 2-deoxyglucose autoradiography and histopathological examination.

In the treatment and therapy of patients suffering a stroke, it is very important to predict whether viable neurones, even those of poor function, remain intact in the lesions of the brain. To determine whether viable neurones of low functional activity are represented in in vivo neuroreceptor imaging, we undertook experiments in gerbils with cerebral infarction, in which we examined histological changes and the results of dual-tracer in vivo autoradiography of glucose utilization with 14C-labelled deoxyglucose and benzodiazepine receptor binding with 123I-labelled Ro 16-0154. The unrelated findings of cerebral glucose metabolism and benzodiazepine receptor binding were observed in the primary infarct lesion and in remote areas, including the ipsilateral striatum and thalamus. Our experiments showed that when viable neurones with low functional activity remain intact, normal in vivo binding to benzodiazepine receptors is demonstrated as hypometabolism of glucose utilization. This functional, contrast-enhanced technique with 123I-labelled Ro 16-0154 may have an important role to play in the prediction of neuronal cell viability after recent brain infarction in experimental animals and humans using single photon emission tomography (SPET).

Animals↗

PubMed1995

Can the microsphere model by applied to cerebral blood flow measurement using N-isopropyl-p-[123I]iodoamphetamine with SPET regardless of washout from brain tissue?

The microsphere model and the continuous withdrawal of arterial blood have commonly been used in clinical studies when measuring regional cerebral blood flow (rCBF) by N-isopropyl-p-[123I]iodoamphetamine (IMP) single photon emission tomography. The method is considered to underestimate rCBF because of the washout of tracer from brain tissue; however, the extent of this underestimation is not known. To assess whether this underestimation can be determined quantitatively, we performed simulation analysis based on the microsphere model and the two-compartment model [influx, K1(rCBF); and outflux, k2(washout)] using the time-activity curves of 123I-IMP in arterial blood [Ca(t)] of 10 subjects. With the microsphere method, rCBF values fell as time post-injection increased. The extent of underestimation of rCBF was 4.7 +/- 0.28% (mean +/- S.D.) at 5 min, 10.2 +/- 0.42% at 10 min and 15.2 +/- 0.55% at 15 min. There was little variation in the extent of underestimation and it was not dependent on the Ca(t) of the subjects. We therefore considered the results to be generally applicable to various studies of the microsphere model. As 4.7% is considered to be negligible in clinical studies, we conclude that the microsphere model can be applied to obtain accurate measurement of rCBF up to 5 min regardless of washout.

Amphetamines↗

PubMed1995

[A fundamental study of 99mTc-HMPAO double injection method and clinical application to stress scintigraphy in orthostatic hypotension].

Double injection method using brain perfusion 99mTc-HMPAO SPECT is popular one for evaluating stress scintigraphy. For appropriate evaluation of this method 555 MBq (15 mCi) of 99mTc-HMPAO was injected twice in sequence at the resting state. The first and second SPECT images were obtained 5 min after each injection. Twenty-five ROIs of 8 x 8 pixels were placed on in various regions of the first images, and calculate each counts (C1). Then the counts of the same region of the second scan were calculated (C2). One hundred and fifty ROIs/6 patients were examined. We derived the linear relationship as C2 = 1.66 x C1 + 106 (r = 0.97), where C1 and C2 represents counts of the first scan, and second scan, respectively. This results suggests that the counts of the second scan is derived from the counts of the first scan without second scanning if they are obtained in the same condition. When we applied this method to stress scintigraphy, it may be useful for evaluating the regional brain perfusion changes before and after loading instead of using subtraction technique.

Aged↗

PubMed1995

[A study on accuracy of rCBF measurements using the conventional microsphere method with N-isopropyl-p-[123I]iodoamphetamine and SPECT].

To evaluate the accuracy of conventional microsphere method for the measurement of regional cerebral blood flow (rCBF) based on the microsphere model with N-isopropyl-p-[123I]iodoamphetamine (123I-IMP) and SPECT, we performed simulation analysis and clinical studies. Although the microsphere method requires early SPECT scan at a few minutes after injection of the tracer for the accurate measurement of rCBF, the conventional microsphere method, which is generally used, requires more delayed SPECT scan with long scan-duration. In the conventional microsphere method, the delayed SPECT image is corrected to the image at a few minutes after injection of the tracer by using the monitored entire brain activity. By the simulation analysis based on the 2-compartment model (influx; K1 and outflux; k2) using the input function and the entire brain activity obtained from eight subjects respectively, it was found that the conventional microsphere method overestimated the rCBF in the practical range of rCBF and Vd (= K1/k2) given in the 2-compartment model. When the values of rCBF and Vd in the 2-compartment model were given at 0.5 (ml/g/min) and 30 (ml/g) respectively, the rate of overestimation of rCBF by the conventional microsphere method was determined to be 17.3 +/- 0.7% (mean +/- S.D.). Also in clinical studies for eight subjects, the conventional microsphere method overestimated the rCBF compared with those evaluated by non-linear least squares fitting (NLLSF) analysis based on the 2-compartment model. Those results agreed well with the simulation analysis, suggesting the validity of the simulation. The rCBF values clinically estimated by the conventional method were, however, significantly correlated with those calculated by NLLSF analysis, and there were not so much difference between the two quantitative rCBF images obtained by the conventional microsphere method and the microsphere method. Therefore, we conclude that the conventional microsphere method is clinically useful in spite of the overestimation of rCBF.

Amphetamines↗

PubMed1995

131I-beta 2-microglobulin scintigraphy in patients with dialysis amyloidosis.

The noninvasive detection of amyloid deposits has recently become possible using scintigraphy with radiolabelled amyloid precursor protein (131I-beta 2-M). We studied 131I-beta 2-M scintigraphy in 15 dialysis patients with special attention to the mechanism of the localized accumulation of tracer. Scintiscans were positive in 8 of the 15 patients. Those with histologically proved amyloid deposits had positive images at the large joints with a continuous accumulation of tracer after 48, 72 and 144 hours. The most significant accumulation occurred bilaterally in the hip joints, followed by the shoulders and knees. Mild uptake was observed in the hands, elbows and feet. No apparent uptake of tracer occurred in patients with secondary hyperparathyroidism, pseudo-gout or AA-type amyloidosis. Three patients were operated for CTS during this study. The radioactivity of tissue excised during the operation was 2-18 times higher than that of fat or plasma. Study of synovial tissue showed that some of the cells surrounding the amyloid deposits took up the radiolabelled tracer. The present study suggests that circulating 131I-beta 2-M is taken up by the cells surrounding the amyloid deposits and detected as a positive scan. It is not known whether these cells react secondarily to amyloid deposits, or whether they take up beta 2-M and form amyloid fibrils.

Adult↗

PubMed1994

Regional cerebral blood flow measured with N-isopropyl-p-[123I]iodoamphetamine single-photon emission tomography in patients with Joseph disease.

Regional cerebral blood flow (rCBF) was measured in five Japanese patients who were clinically diagnosed as having Joseph disease, also called Machado-Joseph disease or Azorean disease, using N-isopropyl-p-[123I]iodoamphetamine (IMP) and single-photon emission tomography (SPECT). Cerebellar atrophy was evaluated by a five-step rating scale as defined on X-ray computed tomography (X-CT). Compared with ten age-matched normal controls (mean cerebellar CBF +/- SD: 66.9 +/- 6.6 ml/100 g/min), rCBF in patients with Joseph disease was significantly decreased in the cerebellum (mean +/- SD: 50.2 +/- 7.3 ml/100 g/min). No significant relationship, however, was found between the decrease in rCBF in the cerebellum and the degree of cerebellar atrophy on X-CT. rCBF in the cerebellum was minimally decreased in one patient who had severe cerebellar atrophy and in two patients with moderate atrophy. These data may support the findings that Purkinje cells in the cerebellum are almost normal in Joseph disease, and that the granular and molecular layers remain intact in spite of cortical atrophy of the cerebellum. It is concluded that [123I]-IMP SPET is able to identify pathological and metabolic changes in the cerebellum that do not appear on X-CT or magnetic resonance imaging, and thus is useful for the diagnosis of Joseph disease.

Adult↗

PubMed1994

A new method of regional cerebral blood flow measurement using one-point arterial sampling based on the microsphere model with N-isopropyl-p-[123I]-iodoamphetamine SPECT.

We developed a new method for quantitative measurement of regional cerebral blood flow (rCBF) using one-point arterial sampling with N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) and single photon emission computed tomography (SPECT) based on the microsphere model. Although the conventional microsphere method requires both the continuous withdrawal of arterial blood (integral of Ca(t)) and treatment of the blood with octanol to obtain the fraction of true tracer activity in the integral of Ca(t) (N), the new method does not require these two procedures. We examined 14 patients to analyse the correlation between the integral of Ca(t)N and a small arterial sample obtained at one time point [one-point Ca(t)] after the injection of 123I-IMP without octanol treatment. The integral of Ca(t)N was calculated from one point Ca(t) using the regression line of the correlation. An error of 8.1% in the calculated value compared to the actual value of the integral of Ca(t)N, could be inferred from one-point Ca(t) obtained at 6 min after the injection. Then regional cerebral blood flow was measured by the method and a significant correlation was obtained with rCBF measured using the 133Xe inhalation method (r = 0.773). The one-point Ca(t) method provides fast, easy, accurate and non-invasive measurement of rCBF without inserting catheters and without treatment of arterial blood with octanol.

Adolescent↗

PubMed1994

[Quantifying regional cerebral blood flow with N-isopropyl-p-[123I]iodoamphetamine and SPECT by one-point sampling method].

We developed a new non-invasive technique; one-point sampling method, for quantitative measurement of regional cerebral blood flow (rCBF) with N-isopropyl-p-[123I]iodoamphetamine and SPECT. Although the continuous withdrawal of arterial blood and octanol treatment of the blood are required in the conventional microsphere method, the new technique does not require these two procedures. The total activity of 123I-IMP obtained by the continuous withdrawal of arterial blood is inferred by the activity of 123I-IMP obtained by the one point arterial sample using a regression line. To determine when one point sampling time was optimum for inferring integral input function of the continuous withdrawal and whether the treatment of sampled blood for octanol fraction was required, we examined a correlation between the total activity of arterial blood withdrawn from 0 to 5 min after the injection and the activity of one point sample obtained at time t, and calculated a regression line. As the results, the minimum % error for the inference using the regression line was obtained at 6 min after the 123I-IMP injection, moreover, the octanol treatment was not required. Then examining an effect on the values of rCBF when the sampling time was deviated from 6 min, we could correct the values in approximately 3% error when the sample was obtained at 6 +/- 1 min after the injection. The one-point sampling method provides accurate and relatively non-invasive measurement of rCBF without octanol extraction of arterial blood.

Adolescent↗

PubMed1994

[A study on evaluation of CBF measurement based on microsphere model with N-isopropyl-p-[123I]iodoamphetamine (IMP) and SPECT--its correction with the value of PaCO2].

To evaluate the regional cerebral blood flow measurement with N-isopropyl-p-[123I]iodoamphetamine (IMP), we performed 123I-IMP SPECT and 133Xe inhalation method on 9 patients with mild cerebrovascular diseases and so on. A tracer dose of 123I-IMP (111 MBq) was injected i.v. and the data were obtained 15 min later. Regional CBF was measured by the microsphere model and arterial blood sampling method. However, mean cerebral blood flow values was not in agreement with both methods. We supposed the reason of the disagreement was due to the difference of PaCO2 when the studies were performed. Hence, CBF measurement with 123I-IMP was performed on the other patient's population with loading of hyperventilation before the IMP injection. Comparing with the control state with normal breathing, we calculated the rate of change of mean CBF between the state with normal breathing and the state with hyperventilation that was 1.02 ml/100 g/min/mmHg PaCO2. After the correction with the rate, we observed a much significant relation between the mean CBF measured with 123I-IMP SPECT and 133Xe inhalation method. When compared CBF values with loading studies or certain therapies, the correction of CBF with the rate of change of PaCO2 is one of the very important factors to be considered. Moreover, 133Xe inhalation method without the correction of PaCO2 can not be a golden standard method for rCBF measurement.

Adult↗

PubMed1994

[A problem of quantitative measurement of regional cerebral blood flow using microsphere model and N-isopropyl-p-[123I]iodoamphetamine (IMP): comparison with 133Xe SPECT and sequential dynamic 123I-IMP SPECT].

Regional cerebral blood flow (rCBF) was measured in 13 patients with various cerebral disease by N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT with the microsphere model (rCBF (CbST)), which was compared with 133Xe inhalation SPECT (rCBFXe). Continuous withdrawal of arterial blood was performed for 5 minutes and SPECT image was obtained from 25 min to 55 min after the tracer injection. The reconstructed counts at 5 min was corrected using entire cerebral counts collected at 5 min, 20 min, and 60 min after the tracer injection. As compared with rCBFXe, rCBF (CbST) was underestimated in high flow areas and overestimated in low flow areas. Regional CBF was also measured using one minute short time SPECT images at 5 min (rCBF (Cb5)), 20 min (rCBF (Cb20)), and 60 min (rCBF (Cb60)) after the injection. Regional CBF tended to be underestimated with time from the tracer injection due to the wash-out from brain tissue to blood. In comparison with rCBF (Cb5), rCBF (CbST) was underestimated in high flow areas and overestimated in low flow areas. This error was considered to be due to the correction of reconstruct counts using entire cerebral counts, because of the kinetic behavior of 123I-IMP was different in each region of the brain.

Adult↗

PubMed1993

SPECT imaging in a case of primary respiratory tract amyloidosis.

SPECT findings in a very rare case of primary amyloidosis localized in the laryngotracheobronchial area are reported. SPECT using Tc-99m PYP revealed widespread uptake in the larynx and the entire tracheobronchial tree up to the subsegmental divisions; the areas corresponded to diffuse thickening and calcification of the walls on CT. SPECT using Ga-67 citrate also showed marked uptake in the same area, consistent with the findings shown by SPECT using Tc-99m PYP.

Adult↗

PubMed1993

Regional cerebral blood flow measured with N-isopropyl-p-[123I]iodoamphetamine and its redistribution in ischemic cerebrovascular disease.

BACKGROUND AND PURPOSE: The relation between the redistribution phenomenon and regional cerebral blood flow and its clinical significance were investigated in stroke patients. METHODS: Single-photon emission computed tomography studies using N-isopropyl-p-[123I]iodoamphetamine were performed on 16 patients (26 to 77 years old) with chronic infarction and 10 age-matched normal control subjects. Regional cerebral blood flow was quantitatively measured by a microsphere model, and the redistribution on delayed images was analyzed in ischemic lesions. RESULTS: Supratentorial mean cerebral blood flow and the ratio of gray matter to white matter in normal subjects were 52.7 +/- 5.0 mL/100 g per minute and 2.34, respectively. Low-activity areas of ischemic lesions on early images were classified into two abnormal zones, an infarct area and a peri-infarct area. These regions were characterized by regional blood flow averaging 9 to 20 mL/100 g per minute and 22 to 41 mL/100 g per minute, respectively. Redistribution, which was minimally present in the infarct area, was markedly enhanced in the peri-infarct area. After bypass surgery, we observed a significant increase of blood flow (+22%) in the peri-infarct area. CONCLUSIONS: The data indicate that the redistribution phenomenon depends on the maintenance of a minimal blood flow that would sustain cellular function and that this phenomenon is useful to evaluate bypass surgery in patients with chronic infarction.

Adult↗

PubMed1993

[A new graphic method for evaluation of distribution volume on N-isopropyl-p-[123I]iodoamphetamine (IMP) SPECT].

We developed a new graphic method using N-isopropyl-p-[123I]iodoamphetamine (IMP) and SPECT of the brain, the graph on which all three parameters, cerebral blood flow, distribution volume (Vd) and delayed count to early count ratio (Delayed/Early ratio), were able to be evaluated simultaneously. The kinetics of 123I-IMP in the brain was analyzed by a 2-compartment model, and a standard input function was prepared by averaging the time activity curves of 123I-IMP in arterial blood on 6 patients with small cerebral infarction etc. including 2 normal controls. Being applied this method to the differential diagnosis between Parkinson's disease and progressive supranuclear palsy, we were able to differentiate both with a glance, because the distribution volume of the frontal lobe significantly decreased in Parkinson's disease (Mean +/- SD; 26 +/- 6 ml/g). This method was clinically useful. We think that the distribution volume of 123I-IMP may reflect its retention mechanism in the brain, and the values are related to amine, especially to dopamine receptors and its metabolism.

Aged↗

PubMed1993

[In vivo autoradiographic benzodiazepine receptor imaging with 125I-iomazenil (Ro 16-0154)].

The biodistribution of 125I-Iomazenil (Ro 16-0154), a benzodiazepine receptor antagonist, was examined using in vivo autoradiography of gerbil brain. 125I-Iomazenil was administrated i.v. into male gerbils, and autoradiography was prepared from coronary sections of the animals decapitated at 5, 60, 120 and 180 min after injection. Initial uptake images (5 min) of 125I-Iomazenil were thought to show blood flow distribution. On the images obtained 120-180 min after administration, high activity of 125I-Iomazenil was observed in the cerebral cortex, amygdala, hippocampus, globus pallidus, thalamus, hypothalamus, superior colliculus, substantia nigra and cerebellar cortex in the areas of which benzodiazepine receptor concentration was reported to be high. However, low activity was observed in the caudate-putamen. Accumulation of 125I-Iomazenil was blocked by pre-administration of flumazenil. 123I-Ro 16-0154 has a high potentiality for benzodiazepine receptor mapping by SPECT.

Animals↗

PubMed1993

[A study of crossed cerebellar diaschisis on 123I-IMP SPECT images and its redistribution phenomenon].

Crossed cerebellar diaschisis (CCD) is interpreted as a functional deactivation, presumably caused by a loss of excitatory or inhibitory afferent inputs on the corticopontocerebellar pathway and others. A redistribution phenomenon (RD) is usually observed in the contralateral cerebellum with CCD on delayed images of 123I-IMP SPECT. This phenomenon was analyzed in a view point of rCBF measurement in 24 patients with brain tumor, infarction and so forth. Regional CBF was measured by the microsphere method with 123I-IMP and a delayed-to-early counts ratio (D/E ratio) was used. As a result, there was no relation between rCBF and the D/E ratio in the cerebellum, which means that RD is occurred by other factors except for rCBF in the cerebellum. Regional CBF and the D/E ratio in the contralateral and ipsilateral cerebellum was 46.3 ml/100 g/min, 1.01 and 57.0 ml/100 g/min, 0.86, respectively. These results mean that the high activity of IMP gradually decreased in the ipsilateral cerebellum, while, the low activity in the contralateral cerebellum was almost stable, and the difference of both activity reduced after 5 hours and RD was observed on the delayed image. The data indicate that retention mechanism of IMP and vascular permeability are not affected in the cerebellum with CCD.

Adolescent↗

PubMed1992

Reduced density of NMDA receptors and increased sensitivity to dizocilpine-induced learning impairment in aged rats.

About 20 min prior to training in a shock-motivated 14-unit T-maze, young (3-4 months) and aged (24-25 months) male Fischer-344 rats were given s.c. injections of either saline or dizocilpine (MK-801, 0.02 or 0.04 mg/kg), a non-competitive antagonist of the N-methyl-D-aspartate (NMDA) receptor. The aged rats showed a dose-dependent impairment in maze performance. Deficiencies were manifested as increases in errors, in runtime from start to goal, and in the number and duration of shocks received. In contrast, young rats exhibited no detrimental effects of dizocilpine on maze performance. Analysis of [3H]glutamate binding in these rats revealed a marked age-related decline in NMDA receptor binding in hippocampus. A significant correlation was observed between errors in the maze and hippocampal [3H]-glutamate binding, but the correlation was positive, i.e., rats that made the most errors had the highest level of NMDA receptor binding. Thus, compared to young rats, aged rats were more sensitive to the behavioral effects of NMDA receptor antagonism and they showed a hippocampal loss of [3H]glutamate in binding, which may be related to the increased sensitivity to dizocilpine. The positive correlation between poor maze performance and NMDA receptor binding suggests that the behaviors assessed involve complex interactions between NMDA receptors and other neuronal systems in the hippocampus.

Aging↗