Publications by authors named "Masatoshi Tsunoda"

We have developed ionic polydimethylsiloxane elastomers that rapidly and reversibly increase their adhesion upon exposure to carbon dioxide (CO) gas. The CO molecules dissolve quickly into the ionic aggregates, physically crosslinking the polymer chains and plasticizing them. The elastomer consequently becomes softer and more adhesive upon exposure to CO.

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Transaortic septal myectomy is a procedure that involves a learning curve for surgeons because the bulging interventricular septum usually interferes with the visualization of the deep parts of the left ventricular chamber. In this case report, we demonstrate computed tomography virtual endoscopy for preoperative simulation, which enabled us to clearly image the relationship among the bulging septum, the expected myectomy area, and the structures deep in the left ventricle, such as the papillary muscle and abnormal muscular bundles, which are hidden by the hypertrophic septum, thus preventing visualization. This approach could make minimally invasive transaortic septal myectomy safe and easy.

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Objective: To assess cerebrospinal fluid (CSF) flow dynamics involvement in the pathogenesis of amyotrophic lateral sclerosis (ALS), we conducted CSF flow studies on 40 individuals with motor neuron diseases (MNDs) including ALS, and 28 age-matched normal and disease [cervical spondylosis (CS)] controls.

Methods: The CSF pulsatile velocity anterior to the cervical cord at level C5 during one heart beat was determined non-invasively by phase-contrast electrocardiography-triggered magnetic resonance imaging.

Results: In MND, caudal CSF velocity peaked at 25% of the cardiac cycle after the R wave (UT(c)/RR), showing an increased delay in comparison to normal controls, while amplitude H(c) was significantly larger than that in CS.

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To determine the efficacy of flow-sensitive alternating inversion recovery using half-Fourier single-shot turbo spin-echo (FAIR-HASTE) in detecting cerebral hypoperfusion in chronic carotid occlusive disease, we subjected 12 patients with various degrees of cervical internal carotid artery stenoses and/or occlusion (Stenosis group) and 24 volunteers (Normal group) to FAIR-HASTE. In addition, 10 out of 12 patients in the Stenosis group underwent dynamic susceptibility contrast-perfusion magnetic resonance imaging (DSC-pMRI) before and after revascularization in the dominantly affected side. The absolute asymmetry indexes (AIs) of both cerebral hemispheres in the Normal and Stenosis groups were compared in FAIR-HASTE.

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The purpose of this study was to evaluate clinically T1-weighted spin-echo imaging (T1-SE) and T1-weighted opposed-phase gradient-echo (T1-opposed GRE) in medical examinations for vertebral metastases using 0.2 Tesla MRI. Twenty-one patients (9 males and 12 females, 105 vertebrae) with non-neoplastic lesions were assigned to the normal group (Group N), whereas 27 patients (16 males and 11 females, 133 vertebrae) with malignant metastatic vertebral lesions were assigned to the metastatic group (Group M).

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Chemical shift MRI is widely used for identifying adenomas, but it is not a perfect method. We determined whether combined dynamic MRI methods can lead to improved diagnostic accuracy. Fifty-seven adrenal masses were examined by chemical shift and dynamic MR imaging using 2 MR systems.

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A new tissue-equivalent MRI phantom based on carrageenan gel was developed. Carrageenan gel is an ideal solidifying agent for making large, strong phantoms in a wide variety of shapes. GdCl(3) was added as a T(1) modifier and agarose as a T(2) modifier.

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Background: Regional dysfunction demonstrated by Tc-99m-diethylenetriamine-penta-acetic acid-galactosyl human serum albumin (GSA) scintigraphy due to regional decrease in the portal venous flow has previously been reported. In this study, we call attention to the significance of unilateral portal venous flow decrease for preoperative hepatectomy simulation, and evaluate the hepatectomy simulation discrepancy between Tc-99m-GSA single-photon emission computed tomography (SPECT) and CT volumetry.

Methods: Twenty-four hepatectomy candidates underwent preoperative hepatectomy simulation by both Tc-99m-GSA SPECT and CT volumetry.

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