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Volume 26 (2009)
- Issue 3 Pages 49-
- Issue 2 Pages 25-
- Issue 1 Pages 1-
Volume 26, Issue 1
Displaying 1-5 of 5 articles from this issue
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Noriyuki TAWARA, Osamu NITTA, Hironobu KURUMA, Mamoru NIITSU, Akiyoshi ...2009 Volume 26 Issue 1 Pages 1-7
Published: 2009
Released on J-STAGE: March 18, 2009
JOURNAL FREE ACCESSExercise induced muscle activity is essential in sports medicine. The previous studies proposed muscle functional magnetic resonance imaging (mfMRI) which visualized muscle activity. However, the mfMRI used the spin echo (SE) sequence, and SE requires several minutes for acquisition time. The purpose of this study was to judge the feasibility of the mfMRI using ultrafast imaging (fast-acquired mfMRI: fast-mfMRI) . The 10 subjects performed 200 repetitions of ankle plantar flexion. T2 relaxation curves of muscle were compared with multiple spin echo (MSE) and spin-echo echo-planar-imaging (SE-EPI) . The fast-mfMRI was the images which the processed images fused into the morphologic images. In the result, there was no problem using the T2 relaxations MR signals from SE-EPI in the range of the short TE. In the fused images, the areas of activated muscle in the fast-mfMRI from the SE-EPI images were in good agreement with that of the fast-mfMRI from the MSE images. In the geometric location of the fast-mfMRI, there was no major difference between the morphologic image and the functional image. Morphological and functional information from the fast-mfMRI can be applied to the human trunk which has a limited scan time.View full abstractDownload PDF (1093K) -
—Development of correction method of SD map using the identical ROI method—Norio HAYASHI, Kaori MINEHIRO, Keita SAKUTA, Toshiaki MIYATI, Shigeru ...2009 Volume 26 Issue 1 Pages 8-12
Published: 2009
Released on J-STAGE: March 18, 2009
JOURNAL FREE ACCESSSignal-to-Noise ratio (SNR) is an important quantity factor used to describe the performance of a magnetic resonance (MR) imaging. However, it is difficult to measure accurately the SNR in clinical parallel MR images. This study is to develop a SNR measurement method using a modified identical region of interest (ROI) technique in clinical parallel MR images. Phantom experiments were performed on a 1.5 and 3.0 Tesla MRI machine to compare three different methods of SNR measurements. We also performed SNR measurements in clinical cases. The method is consisted of the following four steps: 1) Calculation of standard deviation (SD) map 2) Edge detection and removal on SD map 3) Interpolation of the removed edge region 4) Calculation of SNR map using the interpolated SD map. Our developed method were approximately consistent with those of other SNR measurement methods in both phantom and clinical images. In addition, the results of our developed method could measure the SNR in the edge region in parallel MR images. Our method makes it possible to simply and accurately analyze SNR of the clinical parallel image with a single scan.View full abstractDownload PDF (1502K) -
Comparison with count of radioactive isotopeRie TANAKA, Shigeru SANADA, Masaki FUJIMURA, Masahide YASUI, Norio HAY ...2009 Volume 26 Issue 1 Pages 13-16
Published: 2009
Released on J-STAGE: March 18, 2009
JOURNAL FREE ACCESSX-ray translucency of the lungs changes depending on inspired volume. In this study, the usefulness of measuring changes in pixel value on dynamic chest radiographs was assessed in comparison with count of radioactive isotope. In 12 abnormal subjects, there was a good correlation between them (r=0.77) . In eight normal controls, the changes in average pixel value measured in lung unit were almost equal in the right and left lungs, which was consistent with normal respiratory physiology. The results indicated that ventilation performance could be evaluated based on the changes in pixel value on dynamic chest radiographs.View full abstractDownload PDF (431K) -
Naoki OHNO, Tosiaki MIYATI, Mitsuhito MASE, Harumasa KASAI, Hirohito K ...2009 Volume 26 Issue 1 Pages 17-20
Published: 2009
Released on J-STAGE: March 18, 2009
JOURNAL FREE ACCESSWe evaluated regional apparent diffusion coefficient (ADC) change of the brain during the cardiac cycle (ΔADC) . On a 1.5-T MRI, ECG-triggered single-shot diffusion echo planar imaging was used with sensitivity encoding, half scan and rectangular FOV techniques to minimize the bulk motion such as brain pulsation, i.e., data-sampling window of 3ms. ΔADC image was calculated from maximum minus minimum ADC value of all cardiac phase images on a pixel-by-pixel basis. We determined ΔADC in regions of parietal, frontal, temporal and occipital white matters (WM) in twelve healthy volunteers. Moreover, we assessed influences of scan parameters on ΔADC. ΔADC was affected by b-values, but unaffected by voxel size. There was no significant correlation between ΔADC and ADC. The ΔADC values in parietal WM at centrum semiovale level were significantly higher than those in temporal WM at basal ganglia level, although there was no significant difference in ADC values between among WM regions. ΔADC analysis using appropriate scan parameter makes it possible to noninvasively obtain new and more detailed information on the regional brain condition.View full abstractDownload PDF (573K) -
Harumasa KASAI, Toshiaki MIYATI, Miyuki ASAHI, Katsuya KATOH2009 Volume 26 Issue 1 Pages 21-24
Published: 2009
Released on J-STAGE: March 18, 2009
JOURNAL FREE ACCESSThe aim of our study was to compare between fat-suppression method with adiabatic pulse and that without adiabatic pulse, i.e., spectral presaturation with inversion recovery (SPIR) , when radio frequency (RF) penetration affected degree of fat-suppression. We determined the signal change and image uniformity in fat-suppressed area under varying the coil loading with sodium chloride solutions. The adiabatic pulse method showed greater degree of fat-suppression and image uniformity more than SPIR under especially higher density of sodium chloride solutions or a big body if inversion time of the adiabatic pulse method was appropriately set. The adiabatic pulse method makes it possible to evenly suppress the fat signal without affecting the RF penetration.View full abstractDownload PDF (719K)
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