Publications by authors named "Shigeru Nakata"

Aims: This study aimed to evaluate the changes in left ventricular remodelling with time in patients with hypertrophic cardiomyopathy (HCM) using thallium-201 myocardial scintigraphy.

Methods And Results: Forty-eight patients with HCM participated in the study. The extent score (ES) and a newly devised index termed the 'mean count change' (MCC) were used to evaluate the myocardial perfusion defects.

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The aim of this study was to examine whether the heart rate response to adenosine differs after 12 hours [Good control (Good-C)] versus 24 hours [Excellent control (Exc-C)] of caffeine abstinence in adenosine stress thallium-201 (TL) myocardial perfusion imaging (MPI). Patients (n=729) with suspected ischemic heart disease underwent adenosine TL-MPI after 12 (n=226) and 24 (n=503) hours of caffeine abstinence. There was not significant differences between the heart rate of Exc-C and Good-C in 0-2 min after adenosine infusion (0 min 63.

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Adenosine stress myocardial perfusion imaging was performed with an intravenous adenosine and radiopharmaceutical injection in the same line. A syringe containing 720 μg/kg of adenosine in 40 ml of saline was prepared and injected at the constant infusion rate of 400 ml/h. Adenosine was temporarily stopped by the stopcock when 1.

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Background: Although trials of image fusion, such as positron emission computed tomography and multislice spiral computed tomography (MSCT), have already demonstrated clinical usefulness, fusion of the coronary artery image and functional image by MSCT alone has not been reported yet. Here, a new idea of data analysis is proposed in which both regional cardiac function and the responsible coronary arteries can be assessed by a fused image.

Methods And Results: The study group comprised 5 patients with coronary artery disease.

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We examined alteration of regional cerebral blood flow (rCBF) in a case of Alzheimer's disease (AD) patient with musical hallucination. To detect regions related to musical hallucination, single-photon emission computed tomography (SPECT) imaging of the patient and nine sex, age, and cognitive function-matched AD patients without delusions and hallucinations were compared using statistical parametric mapping 99 (SPM99). In comparison with controls, the patient had increased rCBF in left temporal regions and left angular gyrus.

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Objective: It has been reported that delayed scan of thallium-201 (201Tl) scintigraphy is useful for differentiating malignant tumors from benign lesions and for evaluating treatment response. However, physiological muscle uptake which usually increases in delayed scans, often makes it difficult to evaluate 201Tl uptake and its washout in bone and soft-tissue tumors. The purpose of this study was to evaluate whether the delayed scan is necessary and whether a dynamic scan is useful in the evaluation of bone and soft-tissue tumors.

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Background: The beneficial effects of beta-blocker therapy in patients with heart failure have been confirmed. However, the effects of beta-blockers on myocardial perfusion defects are unclear. The aim of this study was to evaluate the effect of beta-blockers on myocardial perfusion defects estimated by thallium-201 myocardial scintigraphy in patients with dilated cardiomyopathy (DCM) and to investigate the relationships between beta-blocker treatment and myocardial damage and cardiac function.

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Purpose: To investigate whether two-phase contrast material-enhanced computed tomographic (CT) findings serve as predictors of changes in left ventricular (LV) function and wall thickness (WT) after acute myocardial infarction (MI) and successful angioplasty.

Materials And Methods: Ethics committee approval and informed consent were obtained. In 58 patients (51 men and seven women; mean age, 62 years +/- 12 [standard deviation]) who had experienced an acute MI and undergone successful angioplasty, two-phase (acquisitions at 45 seconds and 7 minutes) contrast-enhanced CT was performed in the acute (mean interval between treatment and CT, 37 hours +/- 4) and intermediate (mean interval, 28 days +/- 4) periods and for long-term (mean interval, 12 months +/- 4) follow-up.

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We tested the hypothesis that myocardial microvascular abnormalities occur and are influenced by clinical features in 30 patients with hypertrophic cardiomyopathy (HC) using intravenous myocardial contrast echocardiography. Patients with HC were subdivided into 3 groups: nonobstructive HC (n = 12), obstructive HC (n = 10), or HC with systolic dysfunction and heart failure (n = 8). In patients with nonobstructive HC and obstructive HC, subendocardial peak myocardial contrast intensity at the mid-septal area was significantly decreased and the transmyocardial difference of peak myocardial contrast intensity between subendocardial and periendocardial regions at the mid-septal area was significantly related to regional wall thickness.

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This study was performed to evaluate whether thallium-201 myocardial scintigraphy (Tl-201) and iodine-123-metaiodobenzylguanidine (MIBG) myocardial scintigraphy could predict the usefulness of beta-blocker therapy in patients with dilated cardiomyopathy (DCM). Tl-201 and MIBG were performed in 47 patients before beta-blocker therapy. Patients were classified into group A, if their cardiac function improved, and group B, whose function remained unchanged.

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Unlabelled: The purpose of this study was to evaluate the usefulness of SPECT during temporary carotid balloon occlusion testing and to evaluate the changes in regional cerebral blood flow (CBF) and regional cerebral perfusion reserve (CPR) after permanent carotid occlusion.

Methods: Temporary balloon occlusion testing was performed on 40 patients (24 head and neck tumors, 16 aneurysms). During the balloon occlusion (total time, 30 min), (99m)Tc-ethylcysteinate dimer (ECD) was injected intravenously about 5 min before balloon deflation, followed by SPECT data acquisition.

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