Masamitsu Hatakenaka

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PURPOSE the purpose of this study was to examine interhemispheric asymmetry in volume of the caudate nucleus and its age dependency. METHODS high-resolution T1-weighted brain magnetic resonance (MR) images were obtained for each subject using a 3-dimensional fast field-echo pulse sequence. The volumes of the bilateral caudate nuclei on MR images were(More)
BACKGROUND The purpose of this study was to quantify myocardial strain on the subendocardial and epicardial layers of the left ventricle (LV) using tagged cardiovascular magnetic resonance (CMR) and to investigate the transmural degree of contractile impairment in the chronic ischemic myocardium. METHODS 3T tagged CMR was performed at rest in 12 patients(More)
OBJECTIVES To evaluate the usefulness of the signal intensity ratio (SIR) of the optic nerve to the white matter (WM) on short tau inversion recovery (STIR) images to diagnose acute optic neuritis (AON). METHODS The 405 consecutive patients with suspected orbital diseases underwent orbital magnetic resonance imaging (MRI) using a 3-T scanner between June(More)
Our purpose in this study was to evaluate the image quality of low-radiation-dose CT using hybrid iterative reconstruction (HIR), and to compare the results with those of filtered back projection (FBP) at routine doses. We measured the mean values and standard deviation of the CT numbers within and outside a 15-mm low-contrast object cylinder at 1.0%(More)
OBJECTIVE To determine whether joint position affects muscle proton diffusion, fractional anisotropy and primary (lambda(1)), secondary (lambda(2)), and tertiary (lambda(3)) eigenvalues of calf muscles were compared among ankle positions of plantar flexion, intermediate, and dorsiflexion. CONCLUSION In tibialis anterior, fractional anisotropy and(More)
BACKGROUND Persistent muscle contractions during clenching are considered to be one reason for temporomandibular disorders. However, no report has evaluated the effect of clenching on the masticatory muscles, as measured by magnetic resonance imaging (MRI). PURPOSE To investigate whether clenching has an effect on either T(2) or the coefficients for(More)
BACKGROUND The persistent muscle contractions during clenching are thought to cause some temporomandibular disorders. However, no report has so far evaluated the effect of clenching on the masticatory muscles by magnetic resonance imaging (MRI). PURPOSE To investigate the effect of clenching with maximum voluntary contraction on the T(1), T(2), and signal(More)
PURPOSE we assessed the clinical utility of our proposed simplified method for T(1)ρ mapping calculations. MATERIALS AND METHODS ten healthy subjects underwent scanning on a 3-tesla magnetic resonance system using an 8-channel phased-array coil. For each subject, we obtained sagittal T(1)ρ-prepared images using 5 different time of spin-lock pulses (TSL=1,(More)
PURPOSE To determine whether passive muscle extension and contraction affect the proton diffusivity of the muscle. MATERIALS AND METHODS Five male subjects were examined. The fractional anisotropy (FA), and primary (lambda(1)), secondary (lambda(2)), and tertiary eigenvalues (lambda(3)) of the right tibialis anterior and medial gastrocnemius muscles were(More)