Effect of Number of Measurement Points on Accuracy of Muscle T2 Calculations

Tawara, Noriyuki,Nishiyama, Atsushi Korean Society of Magnetic Resonance in Medicine 2016 Investigative Magnetic Resonance Imaging Vol.20 No.4

Purpose: The purpose of this study was to investigate the effect of the number of measurement points on the calculation of transverse relaxation time (T2) with a focus on muscle T2. Materials and Methods: This study assumed that muscle T2 was comprised of a single component. Two phantom types were measured, 1 each for long ("phantom") and short T2 ("polyvinyl alcohol gel"). Right calf muscle T2 measurements were conducted in 9 healthy male volunteers using multiple-spin-echo magnetic resonance imaging. For phantoms and muscle (medial gastrocnemius), 5 regions of interests were selected. All region of interest values were expressed as the mean ${\pm}$ standard deviation. The T2 effective signal-ratio characteristics were used as an index to evaluate the magnetic resonance image quality for the calculation of T2 from T2-weighted images. The T2 accuracy was evaluated to determine the T2 reproducibility and the goodness-of-fit from the probability Q. Results: For the phantom and polyvinyl alcohol gel, the standard deviation of the magnetic resonance image signal at each echo time was narrow and mono-exponential, which caused large variations in the muscle T2 decay curves. The T2 effective signal-ratio change varied with T2, with the greatest decreases apparent for a short T2. There were no significant differences in T2 reproducibility when > 3 measurement points were used. There were no significant differences in goodness-of-fit when > 6 measurement points were used. Although the measurement point evaluations were stable when > 3 measurement points were used, calculation of T2 using 4 measurement points had the highest accuracy according to the goodness-of-fit. Even if the number of measurement points was increased, there was little improvement in the probability Q. Conclusion: Four measurement points gave excellent reproducibility and goodness-of-fit when muscle T2 was considered mono-exponential.

Muscle Functional MRI of Exercise-Induced Rotator Cuff Muscles

Tawara, Noriyuki,Nishiyama, Atsushi Korean Society of Magnetic Resonance in Medicine 2021 Investigative Magnetic Resonance Imaging Vol.25 No.1

The aim of this study was to provide a new assessment of rotator cuff muscle activity. Eight male subjects (24.7 ± 3.2 years old,171.2 ± 9.8 cm tall, and weighing 63.8 ± 11.9 kg) performed the study exercises. The subjects performed 10 sets of the exercise while fixing the elbow at 90 degrees flexure and lying supine on a bed. One exercise set consisted of the subject performing external shoulder rotation 50 times using training equipment. Two imaging protocols were employed: (a) true fast imaging with steady precession (TrueFISP) at an acquisition time of 12 seconds and (b) multi-shot spin-echo echo-planar imaging (MSSE-EPI) at an acquisition time of 30 seconds for one echo. The main method of assessing rotator cuff muscle activity was functional T2 mapping using ultrafast imaging (fast-acquired muscle functional MRI [fast-mfMRI]). Fast-mfMRI enabled real-time imaging for the identification and evaluation of the degree of muscle activity induced by the exercise. Regions of interest were set at several places in the musculus subscapularis (sub), musculus supraspinatus (sup), musculus teres minor (ter), and deltoid muscle (del). We used the MR signal of the images and transverse relaxation time (T2) for comparison. Most of the TrueFISP signal was not changed by exercise and there was no significant difference from the resting values. Only the T2 in the musculus teres minor was increased after one set and the change were seen on the T2 images. Additionally, except for those after one and two sets, the changes in T2 were significant compared to those at rest (P < 0.01). We also demonstrated identify and visualize the extent to which muscles involved in muscle activity by exercise. In addition, we showed that muscle activity in a region such as a shoulder, which is susceptible to B0 inhomogeneity, could be easily detected using this technique.

Effect of Number of Measurement Points on Accuracy of Muscle T2 Calculations

Noriyuki Tawara,Atsushi Nishiyama 대한자기공명의과학회 2016 Investigative Magnetic Resonance Imaging Vol.20 No.4

Purpose: The purpose of this study was to investigate the effect of the number of measurement points on the calculation of transverse relaxation time (T2) with a focus on muscle T2. Materials and Methods: This study assumed that muscle T2 was comprised of a single component. Two phantom types were measured, 1 each for long (“phantom”) and short T2 (“polyvinyl alcohol gel”). Right calf muscle T2 measurements were conducted in 9 healthy male volunteers using multiple-spin-echo magnetic resonance imaging. For phantoms and muscle (medial gastrocnemius), 5 regions of interests were selected. All region of interest values were expressed as the mean ± standard deviation. The T2 effective signal-ratio characteristics were used as an index to evaluate the magnetic resonance image quality for the calculation of T2 from T2- weighted images. The T2 accuracy was evaluated to determine the T2 reproducibility and the goodness-of-fit from the probability Q. Results: For the phantom and polyvinyl alcohol gel, the standard deviation of the magnetic resonance image signal at each echo time was narrow and monoexponential, which caused large variations in the muscle T2 decay curves. The T2 effective signal-ratio change varied with T2, with the greatest decreases apparent for a short T2. There were no significant differences in T2 reproducibility when > 3 measurement points were used. There were no significant differences in goodnessof- fit when > 6 measurement points were used. Although the measurement point evaluations were stable when > 3 measurement points were used, calculation of T2 using 4 measurement points had the highest accuracy according to the goodnessof- fit. Even if the number of measurement points was increased, there was little improvement in the probability Q. Conclusion: Four measurement points gave excellent reproducibility and goodnessof- fit when muscle T2 was considered mono-exponential.

The Ability of Muscle Functional MRI to Detect the Slight Effect of Exercise on Trunk Muscle Activity

Noriyuki Tawara 대한자기공명의과학회 2022 Investigative Magnetic Resonance Imaging Vol.26 No.2

Purpose: In this study, we provide a way to assess even a slight effect of exercise on trunk-muscle activity. Materials and Methods: Seven healthy male participants (mean age, 24.7 ± 3.2 years; height, 171.2 ± 9.8 cm; and weight, 63.8 ± 11.9 kg) performed 15 sets of an exercise with 20 repetitions of 90˚ hip and right-knee flexion while lying supine. The exercise intensity was measured using the 10-point Rating of Perceived Exertion Scale after the first and 15th sets of exercises. Although cross-sectional areas and functional T2 mapping using ultrafast imaging (fast-acquired muscle functional magnetic resonance imaging, fast-mfMRI) have been proposed for imaging to evaluate exercise-induced muscle activity in real time, no previous studies have reported on the evaluation of trunk-muscle activity using functional T2 mapping. As a method for assessing trunk-muscle activity, we compared functional T2 mapping using ultrafast imaging (fast-mfMRI) with cross-sectional areas. Results: Although the muscle cross-sectional areas were increased by the exercise, there was no significant difference at rest. On the other hand, for all sets, the changes in T2 were significant compared with those at rest (P < 0.01). These results demonstrate that T2, calculated from fast-mfMRI images can be used to detect even a small amount of muscle activity induced by acute exercise, which was impossible to do with cross-sectional areas. Conclusion: Fast-mfMRI, which can also display functional information with detailed forms, enabled non-invasive real-time imaging for identifying and evaluating the degree of deep trunk-muscle activity induced by exercise.

Development of modeling and analysis techniques for information sharing on supply chain

Yasutaka Kainuma,Nobuhiko Tawara 한국경영정보학회 2000 한국경영정보학회 학술대회논문집 Vol.2000 No.-

얀세의 「인도차이나 고고 조사」에 관한 歷史的 검토

俵寛,司(Tawara, Kanji) 중앙문화재연구원 2013 중앙고고연구 Vol.0 No.13

본고는 프랑스령 인도차이나 시대의 베트남에 있어서 스웨덴의 고고학자인 올로브 얀세(Olov R. T. Jans e :1892~1985)에 의해 1930년대에 발굴되어 현재 베트남 국내외에 소장되어 있는「인도차이나 고고조사 ｣자료에 관한 학사적 검토이다. 프랑스령 인도차이나 시대의 베트남에 있어서 얀세의 조사연구는 「동양고고학 ｣이 시작된 것으로 생각된다. 그 배경에는 프랑스의 동양 학/동양학적 고고학의 지식과 더불어 유럽과 미국에 동양컬렉션의 축적이 있었고, 더욱이 자연 과학적・인류학적인 「고고학 ｣의 방법론이나 조사기술 등의 「규범 ｣도 도입된 것으로 보인다. 프랑스령 인도차이나 시대에서 제2차 세계대전 후의 국민국가(민족국가) 베트남의 성립에 걸쳐 있는 얀세자료를 둘러싼 역사적・사회적인 자리매김도 크게 변화되었지만 남아있는 자료는 여전히 방대하다. 역동적으로 변화하고 있는 현재의 베트남에 있어서 이것들을 얼마나 복원해 활용해 나가는가가 차후의 커다란 과제가 될 것이다. This paper is a historical study on the materials of the Archaeological Research in Indo-china, which was conducted by a Swedish archaeologist, Olov R. T. Janse (1892~1985) 1930s in French Indo-china period in Viet Nam. His researches could be estimated the earliest practice on the Far Eastern Archaeology/East Asian Archaeology in this field. Such activities were founded by knowledge from French school of Orientalism/Oriental Archaeology and accumulations of the Eastern collections in Europe. And that was also introduced by the models of methods and techniques from Scientific/Anthropological archaeology. During the French Indochina period and the independent nation state of Viet Nam after World War II, historical and social positions around the materials, Olov Janse collections were changed, but huge amount of the materials were left. Our tasks are how can we restore and use the materials for the future.

Output Polarization Direction Control with a Constant Power Independent of Input Polarization Direction

Mitsuhiro Tateda,Tomoaki Tawara,Takashige Omastsu,Akira Hasegawa 한국통신학회 1997 OPTOELECTRONICS & COMMUNICATIONS CONFERENCE Vol.2 No.1

회전 및 다상유동을 고려한 자동변속기의 윤활배분 예측기술의 개발

윤두희(Doohee Yoon),타와라유키(Yuki Tawara),김주성(Jusei Kin),아사하라타케히토(Takehito Asahara),김창현(Changhyun Kim) 한국자동차공학회 2016 한국자동차공학회 부문종합 학술대회 Vol.2016 No.5

Electron loss of fast many-electron ions colliding with neutral atoms: possible scaling rules for the total cross sections

Shevelko, V P,Litsarev, M S,Song, M-Y,Tawara, H,Yoon, J-S IOP Pub 2009 Journal of Physics B: Atomic, Molecular and Optica Vol.42 No.6

<P>General features of the total electron-loss (projectile ionization) cross sections, sigma(tot), for fast many-electron ions colliding with neutral atoms are investigated. Two independent scaling laws for sigma(tot) are obtained: one follows from the experimental data and another one from the classical calculations based on the n-particle classical trajectory Monte Carlo (nCTMC) and semi-classical treatments. The semi-classical method has recently been developed based upon the energy deposition model and the statistical ionization probabilities. Both scaling relations are expressed in terms of the projectile velocity v, its first ionization potential I-1 and the nuclear charge Z(A) of the target atom. The accuracy of the scaling relations suggested is a factor of 2-3. At the high-velocity region (nu(2) >> I-1), experimental data are found to decrease approximately as sigma(tot) similar to nu(-2), i. e., close to the Born ionization cross section. At low energies, the stot values are better described by the classical approximation which accounts for multi-electron-loss processes. These scaling laws obtained are compared with a known scaling law for the Ar target and are used for the prediction of the total electron-loss cross sections in a wide range of the collision parameters. The predicted cross sections sigma(tot) can be approximately evaluated as a minimum cross section obtained from two scaling formulae.</P>

TRACING BRIGHT AND DARK SIDES OF THE UNIVERSE WITH X-RAY OBSERVATIONS

SUTO YASUSHI,YOSHIKAWA KOHJI,DOLAG KLAUS,SASAKI SHIN,YAMASAKI NORIKO Y.,OHASHI TAKAYA,MITSUDA KAZUHISA,TAWARA YUZURU,FUJIMOTO RYUICHI,FURUSHO TAE,FURUZAWA AKIHIRO,ISHIDA MANABU,ISHISAKI YOSHITAKA The Korean Astronomical Society 2004 Journal of The Korean Astronomical Society Vol.37 No.5

X-ray observations of galaxy clusters have played an important role in cosmology, especially in determining the cosmological density parameter and the fluctuation amplitude. While they represent the bright side of the universe together with the other probes including the cosmic microwave background and the Type Ia supernovae, the resulting information clearly indicates that the universe is dominated by dark components. Even most of cosmic baryons turns out to be dark. In order to elucidate the nature of dark baryons, we propose a dedicated soft-X-ray mission, DIOS (Diffuse Intergalactic Oxygen Surveyor). Recent numerical simulations suggest that approximately 30 to 50 percent of total baryons at z = 0 take the form of the warm-hot intergalactic medium (WHIM) with $10^5K < T < 10^7K $which has evaded the direct detection so far. The unprecedented energy resolution (${\~} 2eV$) of the XSA (X-ray Spectrometer Array) on-board DIGS enables us to identify WHIM with gas temperature $T = 10^6 {\~} 10^7K$ and overdensity $\delta$ = 10 ${\~}$ 100 located at z < 0.3 through emission lines of OVII and OVIII. In addition, WHIMs surrounding nearby clusters are detectable with a typical exposure time of a day, and thus constitute realistic and promising targets for DIOS.