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Biomedical subjects

Tsunehiko Nishimura

Publications and source records attributed to Tsunehiko Nishimura.

At least 55 records · Page 3Linked to original sources
PubMed2005

Influence of hepatopetal flow of the retroportal artery on efficiency of repeated hepatic arterial infusion chemotherapy.

Few reports have described the influence of the retroportal artery on the distribution of anticancer drugs in the liver during repeated hepatic arterial infusion chemotherapy. This report describes two patients in whom poor distribution was observed in the right lobe of the liver, which was confirmed at superior mesenteric arteriography to be caused by inflow of the retroportal artery to the right hepatic artery. The retroportal artery was successfully embolized, resulting in improvement of distribution in the right lobe of the liver in both cases.

Aged↗
PubMed2005

Efficacy of the left gastric artery as a route for catheterization of the right gastric artery.

OBJECTIVE: Our aim was to evaluate the efficacy of the left gastric artery as a route for embolization of the right gastric artery before port-catheter implantation for hepatic artery infusion chemotherapy. MATERIALS AND METHODS: In 88 patients (61 men and 27 women; mean age, 63.4 years; range, 25-83 years) with unresectable advanced liver cancer, retrograde catheterization of the right gastric artery through the left gastric artery was performed to embolize the right gastric artery. RESULTS: The right gastric artery was successfully catheterized and embolized in 79 patients (89.8%). In two of the nine patients in whom the procedure was not successful, we found that no right gastric artery existed after we succeeded in retrograde advancement of the microcatheter toward the hepatic site. The only procedure-related complication was misplacement of a microcoil into the hepatic artery site in two patients. CONCLUSION: The left gastric artery is an appropriate route for selective embolization of the right gastric artery as preparation for long-term hepatic artery infusion chemotherapy.

Adult↗
PubMed2005

Management of end hole in placement of port-catheter system for continuous hepatic arterial infusion chemotherapy using the fixed catheter tip method.

OBJECTIVE: The purpose of our study was to compare persistent hepatofugal blood flow in the gastroduodenal artery after implanting a port-catheter system for repeated hepatic arterial infusion chemotherapy using either the original or the modified fixed catheter tip method. With the original method the lumen of the catheter tip is closed with a microcoil; with the modified method it is left open. Persistent hepatofugal blood flow can induce reactive gastric or duodenal mucosal lesions. MATERIALS AND METHODS: A port-catheter system with the catheter tip fixed to the gastroduodenal artery by embolic agents was percutaneously implanted in 156 patients (102 men, 54 women; mean age, 63.2 years) with unresectable liver cancer. In 98 patients the original method was used, and in 58 patients the modified method was used. Existence of persistent blood flow beyond the indwelling catheter tip as shown on arteriography via the port performed immediately and 2-10 days after port-catheter placement was compared between these two groups. RESULTS: In all cases, percutaneous port-catheter placement was successfully performed. In one (1.0%) of 98 procedures involving the original method, the gastroduodenal artery was detected on arteriography just after implantation, compared with 23 (39.7%) of 58 procedures using the modified method. However, arteriography performed 2-10 days (mean, 5.02 days) after implantation detected the gastroduodenal artery in only one case. CONCLUSION: This retrospective study indicates that closure of the end hole appears to occur spontaneously shortly after implantation. Thus, such closure is not always necessary to avoid persistent hepatofugal blood flow in the gastroduodenal artery.

Adult↗
PubMed2005

Effect of thin-section diffusion-weighted MR imaging on stroke diagnosis.

BACKGROUND AND PURPOSE: Diffusion-weighted (DW) imaging has limited spatial resolution, especially in the z direction. We decreased the section thickness of DW imaging to 3 mm to determine if this change improves the depiction of small infarcts and if it affects stroke diagnosis. METHODS: We studied conventional (5-mm section thickness, 1-mm intersection gap) and thin-section (3-mm section thickness, no intersection gap) DW imaging data in 49 patients with symptoms of acute cerebral ischemia. Two radiologists who were not aware of the clinical findings reviewed all images and diagnosed the stroke subtype according to the Trial of Org 10172 in Acute Stroke Treatment (TOAST) method. Accuracies of stroke diagnosis with an experienced neuroradiologist and with a second-year radiology resident were compared. To quantify lesion conspicuity, contrast-to-noise ratios (CNRs) were measured. The CNR of thin-section DW imaging was then divided by the CNR of conventional DW imaging to yield the relative CNR (rCNR). RESULTS: The experienced neuroradiologist made the correct final diagnoses in 78% of cases with conventional DW imaging, improving to 100% with thin-section DW imaging. The resident made the correct diagnoses in 71% of cases with conventional DW imaging, improving to 94% with thin-section DW imaging. Lesion conspicuity was improved on thin-section DW imaging (rCNR = 1.47 +/- 0.63), especially for supratentorial lesions (rCNR = 1.51 +/- 0.63). CONCLUSION: Compared with conventional DW imaging, thin-section DW imaging permitted better lesion conspicuity and more precise stroke diagnosis.

Aged↗
PubMed2005

Tractography for arteriovenous malformations near the sensorimotor cortices.

We sought to use diffusion-tensor imaging-based tractography to assess the relationship between the arteriovenous malformations (AVM) and the sensorimotor cortices/tracts. Three patients who had an AVM closely situated to the sensorimotor tracts were studied. The relationship between the sensorimotor tracts and the AVM was well demonstrated in all patients. Tractography was also helpful in identifying the location of the motor cortex in some of the cases.

Adult↗
PubMed2004

Diagnosis of Alzheimer's disease using brain perfusion SPECT and MR imaging: which modality achieves better diagnostic accuracy?

PURPOSE: The purpose of this study was to compare the accuracy of MR imaging and brain perfusion single-photon emission tomography (SPECT) in diagnosing Alzheimer's disease (AD). METHODS: The transaxial section display of brain perfusion SPECT, three-dimensional stereotactic surface projection (3D-SSP) SPECT image sets, thin-section MR imaging of the hippocampus and perfusion MR imaging were evaluated in 66 subjects comprising 35 AD patients and 31 subjects without AD. SPECT and MR imaging were visually interpreted by two experts and two novices, and the diagnostic ability of each modality was evaluated by receiver operating characteristic (ROC) analysis. RESULTS: In the experts' interpretations, there was no significant difference in the area under the ROC curve (Az) between 3D-SSP and thin-section MR imaging, whereas the Az of transaxial SPECT display was significantly lower than that of 3D-SSP (3D-SSP: 0.97, thin-section MR imaging: 0.96, transaxial SPECT: 0.91), and the Az of perfusion MR imaging was lowest (0.63). The sensitivity and specificity of each modality were, respectively, 80.0% and 96.8% for 3D-SSP, 77.1% and 96.8% for thin-section MR imaging, 60.0% and 93.5% for transaxial SPECT display and 34.3% and 100% for perfusion MR imaging. In the novices' interpretations, the Az, sensitivity and specificity of 3D-SSP were superior to those of thin-section MR imaging. CONCLUSION: Thin-section hippocampal MR imaging and 3D-SSP image sets had potentially equivalent value for the diagnosis of AD, and they were superior to transaxial SPECT display and perfusion MR imaging. For avoidance of the effect of interpreters' experience on image evaluation, 3D-SSP appears to be optimal.

Aged↗
PubMed2004

Effect of rolipram on relative 14C-deoxyglucose uptake in inflammatory lesions and skeletal muscle.

PURPOSE: 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) has become a useful imaging tool for inflammatory diseases. In this study we investigated the effects of rolipram, a selective phosphodiesterase type 4 inhibitor, on 14C-deoxyglucose (DG) uptake in inflammatory lesions and other normal tissues, and attempted to improve the inflammation/muscle ratio. METHODS: To induce inflammation, mice were inoculated with turpentine oil. Inflammation-bearing mice were pretreated with rolipram (3 mg/kg i.p. or i.v.), and the effect on 14C-DG uptake was measured using a tissue dissection method and autoradiography. The inflammatory tissue samples were stained with haematoxylin and eosin. RESULTS: Rolipram (3 mg/kg i.p.) significantly decreased 14C-DG uptake in normal tissues like brain, heart and skeletal muscle (brain 31%, heart 60%, skeletal muscle 61%). On the other hand, 14C-DG uptake in inflammatory lesions was not significantly altered by pretreatment with rolipram. The inflammation/muscle ratio of 14C-DG uptake (30 min after tracer injection) was enhanced from 1.1 to 2.8 by rolipram. An autoradiographic study revealed heterogeneous distributions of 14C-DG in the inflammatory lesions and skeletal muscle of animals that were not treated with rolipram. Pretreatment with rolipram significantly attenuated the intramuscular distribution of 14C-DG, producing a relatively homogeneous distribution of radioactivity. CONCLUSION: These results indicate that rolipram decreased 14C-DG uptake in skeletal muscle by activation of the adenosine 3',5'-cyclic monophosphate system, whereas 14C-DG uptake in inflammatory lesions was not significantly altered. Therefore, rolipram may be a valuable tool for improving the visualisation of inflammatory lesions in clinical PET studies employing FDG.

Animals↗
PubMed2004

Value of transcatheter arterial embolization with coils and n-butyl cyanoacrylate for long-term hepatic arterial infusion chemotherapy.

PURPOSE: To assess the value of transcatheter arterial embolization (TAE) of splanchnic arterial branches to allow continuous application of repeat hepatic arterial infusion chemotherapy (HAIC). MATERIALS AND METHODS: In 128 patients with unresectable advanced liver cancer, percutaneous implantation of a port catheter system and TAE of splanchnic arteries with coils and/or n-butyl cyanoacrylate (NBCA) were performed. Parameters included (a) methods selected for catheter placement; (b) embolic materials used (coils and/or NBCA, number of coils, administration rate of NBCA-iodized oil) for TAE of splanchnic arteries, details of embolized arteries, and frequency of recanalization; (c) ability to prevent gastrointestinal symptoms by avoiding inflow of anticancer drugs into extrahepatic adjacent organs and to maintain distribution of contrast agents in liver, as well as management of difficulties encountered; (d) complications related to catheter system implantation or to long-term HAIC and management of such complications; and (e) final success in performing scheduled HAIC while maintaining distribution over liver via a single route without gastrointestinal symptoms caused by inflow of anticancer drugs. Fisher exact test was used to compare recanalization rate between coil-embolized and NBCA- or NBCA-coil-embolized arteries, and frequency of heterogeneously poor distribution was compared between patients with single and those with multiple hepatic arteries. RESULTS: Embolization was successful during first catheterization in 326 arteries and during follow-up in 10. In 119 (93.0%) of 128 patients, repeat HAIC was effective until death or the time of this writing (observation period, 2-47 months). HAIC was continued in two patients, although anticancer drugs did not distribute to all liver tumors. Arteries once embolized with coils alone spontaneously recanalized at a significantly higher rate than those with NBCA (eight of 192 vs one of 144, P =.048). Rate of heterogeneously poor distribution was significantly higher in those with two or more hepatic arteries than in those with one (seven of 17 vs nine of 111, P =.001). CONCLUSION: TAE for various splanchnic organs is useful for efficient performance of long-term HAIC.

Adult↗
PubMed2004

Myocardial positron emission computed tomographic images obtained with fluorine-18 fluoro-2-deoxyglucose predict the response of idiopathic dilated cardiomyopathy patients to beta-blockers.

OBJECTIVES: The aim of this study was to elucidate whether the response of idiopathic dilated cardiomyopathy (DCM) patients to beta-blockers can be predicted by positron emission tomography with fluorine-18 fluoro-2-deoxyglucose (FDG-PET). BACKGROUND: Patients with DCM often have a poor prognosis, and it is important to predict their response to beta-blocker therapy, which may be effective in DCM. However, no accurate methods of predicting their response have been available. METHOD: In 22 DCM patients with reduced left ventricular (LV) systolic function, FDG-PET was performed. Uptake in the LV after glucose loading was evaluated based on the average global percent uptake of the injected dose (G%ID) and the coefficient of variance (CV) in 24 segments of the LV. Uptake during fasting was evaluated semiquantitatively on the basis of the total uptake score. The beta-blocker was administered, and LV function was monitored by echocardiography. The histologic findings were assessed in the 18 patients who underwent endomyocardial biopsy. RESULTS: The beta-blocker was effective in the majority of patients whose G%ID after glucose loading was >0.7%, and the sensitivity and specificity of G%ID as a predictor of beta-blocker efficacy were 83.3% and 90.0%, respectively. Percent CV did not predict efficacy. Four groups, defined on the basis of the FDG uptake score during fasting and G%ID after glucose loading, had distinctive histologic findings and outcomes. CONCLUSIONS: It has been shown that FDG-PET is a good predictor for the effectiveness of beta-blockers.

Adrenergic beta-Antagonists↗
PubMed2004

Uncoupling of flow and metabolism induced by sodium nitroprusside in rat cerebral cortex.

The effects of sodium nitroprusside (SNP) on cerebral blood flow and glucose metabolism were investigated by the microinfusion of SNP into rat cerebral cortex. A significant enhancement in glucose metabolism, as measured using [14C]deoxyglucose (DG), was observed throughout widespread areas of the cerebral cortex within 1 h of microinjection of 50 nmol/microl SNP. Using a kinetic analysis, the increase in glucose metabolism was found to be due to an increase in the phosphorylation of [14C]DG in the brain. On the other hand, regional cerebral blood flow, as measured using [14C]iodoantypirine, was not significantly altered by the SNP infusion. No significant cell death was detected by 2,3,5-triphenyltetrazolium chloride (TTC) staining 1 h after the SNP infusion. The uncoupling of flow and metabolism was almost completely prevented by pretreatment with an NMDA antagonist, MK-801. However, pretreatment with MK-801 did not prevent the SNP-induced neural cell death detected 6 h after the SNP infusion. These results suggest that the SNP-induced uncoupling of flow and metabolism was not directly related to neural cell death in the cerebral cortex.

Animals↗
PubMed2004

Equivalent cross-relaxation rate imaging of breast cancer.

PURPOSE: To determine whether equivalent cross-relaxation rate (ECR) imaging is a feasible method for demonstrating breast cancer. MATERIALS AND METHODS: Fifteen breast cancer patients underwent both ECR imaging, with off-resonance saturation pulses at frequency offsets of 7 and 19 ppm (ECR-7 and ECR-19, respectively) from water resonance, and gadolinium (Gd)-enhanced dynamic magnetic resonance imaging (MRI) of the breast. The mean tumor size was 26.5 mm. The tumor outlines defined by their shape and margin on ECR-7 images were compared with the subtraction images produced by the dynamic study, and the distribution of hyperintensity areas and their shapes on ECR-19 images were assessed. All patients had surgery and pathological findings were compared to ECR images. RESULTS: The tumor outline of 13/15 (87%) tumors on ECR-7 images was nearly identical to that on subtraction images; ECR-19 images demonstrated the location and degree of fibrosis. The tumor outline of the other two tumors was less clear on ECR-7 images, and internal hyperintensity on ECR-19 images reflected intratumoral fibrotic foci. ECR-7 and -19 imaging findings allowed identification of four distinct tumor types that reflected the tumor growth patterns and their internal structures associated with fibrosis. CONCLUSION: ECR imaging is a feasible imaging technique for demonstrating breast cancer.

Adult↗
PubMed2004

Stroke patients' evolving symptoms assessed by tractography.

PURPOSE: To test the hypothesis that an interval evolution in the location of the depicted sensorimotor tract relative to the infarct (the "tract-infarct relationship") may be related to stroke victims' symptom progression. MATERIALS AND METHODS: Patients (N = 7) who underwent multiple diffusion-tensor imaging (DTI) studies during symptomatic progression were included in this study. DTI was performed using a single-shot echo-planar imaging (EPI) technique with a motion-probing gradient in six orientations, a b-value of 800 seconds/mm2, and six image averages. The total scan time was four minutes and 24 seconds. Fiber-tracking of the sensorimotor pathways was performed, and the locations of these tracts were retrospectively assessed in relation to the evolution of the symptoms. RESULTS: Five of the seven patients showed an interval enlargement of the infarct on diffusion-weighted (DW) images. In two of these cases the lesion enlarged to involve the sensorimotor tracts, while in three cases the lesion enlarged only so far to come into close proximity to the sensorimotor tract. In the remaining two cases there was no interval enlargement of the infarct, and therefore the tract-infarct relationship could not account for the evolution of the symptoms in these cases. CONCLUSION: A tract-infarct relationship can be observed with the use of a fiber-tracking technique, and the results may improve our understanding of the symptom progression seen in stroke victims.

Adult↗
PubMed2004

Evaluation of the use of a standard input function for compartment analysis of [123I]iomazenil data: factors influencing the quantitative results.

Adoption of standard input function (SIF) has been proposed for kinetic analysis of receptor binding potential (BP), instead of invasive frequent arterial samplings. The purpose of this study was to assess the SIF method in quantitative analysis of [123I]iomazenil (IMZ), a central benzodiazepine antagonist, for SPECT. SPECT studies were performed on 10 patients with cerebrovascular disease or Alzheimer disease. Intermittent dynamic SPECT scans were performed from 0 to 201 min after IMZ-injection. BPs calculated from SIFs obtained from normal volunteers (BPs) were compared with those of individual arterial samplings (BPo). Good correlations were shown between BP(o)s and BP(s)s in the 9 subjects, but maximum BP(s)s were four times larger than the corresponding BP(o)s in one case. There were no abnormal laboratory data in this patient, but the relative arterial input count in the late period was higher than the SIF. Simulation studies with modified input functions revealed that height in the late period can produce significant errors in estimated BPs. These results suggested that the simplified method with one-point arterial sampling and SIF can not be applied clinically. One additional arterial sampling in the late period may be useful.

Adolescent↗
PubMed2004

Pattern of 111In-chloride bone marrow scintigraphy in myelodysplastic syndrome; comparison with clinical characteristics.

111In-chloride bone marrow scintigraphy (bone marrow scintigraphy) was performed in patients with myelodysplastic syndrome (MDS), tracer accumulation was classified into patterns, and the relationship between the accumulation patterns and prognostic factors was investigated to assess the usefulness of bone marrow scintigraphy. The subjects were 14 patients diagnosed with MDS. Accumulation of the bone marrow scintigraphy tracer was classified according to the degree of accumulation in the axial bone marrow and peripheral expansion. International Prognostic Scoring System (IPSS), which are frequently used for prognostic evaluation of MDS, and conversion to leukemia were investigated in prognostic factors. We also investigated the relationship between enlargement of the liver and spleen and the prognostic factors. The accumulation patterns were as follows: pattern I, The normal accumulation pattern (2 cases); pattern II, the expanded accumulation pattern (6 cases); pattern III, low accumulation pattern (5 cases); and pattern IV, heterogeneous accumulation pattern (1 case). The relationships between the two prognostic factors and accumulation patterns were investigated, and the prognosis was found to be significantly poorer in the patients with the low accumulation pattern than the expanded accumulation pattern. Enlargement of the liver and spleen was not significantly correlated with the prognostic factors.

Adult↗
PubMed2004

Oestrogen increases myocardial blood flow in men: assessment by 13N-ammonia positron emission tomography.

OBJECTIVES: Oestrogen has been shown to increase nitric oxide-mediated vasodilatation and modulate sympathetic tone in postmenopausal women. We investigated the acute effects of oestrogen on the coronary microcirculation in men. METHODS: Myocardial blood flow was quantified using N-ammonia positron emission tomography before and 20 min after an intravenous administration of conjugated oestrogen (10 mg) in nine healthy men. RESULTS: There were no significant changes in either systemic blood pressure or heart rate before and after oestrogen infusion. However, myocardial blood flow was increased by oestrogen from 0.88 +/-0.06 to 1.05+/-0.09 ml x g x min (P<0.05). Although serum levels of nitrite/nitrate (end products of nitric oxide) were not increased, circulating norepinephrine (noradrenaline) levels were decreased after the administration of oestrogen from 401+/-114 to 346+/-112 pg x ml (P<0.01). A significant negative correlation was found between myocardial blood flow and plasma norepinephrine levels (r=-0.67, P<0.05). CONCLUSIONS: A single administration of oestrogen enhanced myocardial circulation in healthy men. The oestrogen-induced increase in myocardial blood flow may be due to direct effects on the coronary circulation or through the modulation of norepinephrine levels, rather than the production of nitric oxide.

Adult↗