Determination of Optimal Scan Time for the Measurement of Downstream Metabolites in Hyperpolarized 13C MRSI

이한솔,이준성,조은혜,양승욱,최영숙,왕은경,송호택,김동현 대한자기공명의과학회 2015 Investigative Magnetic Resonance Imaging Vol.19 No.4

Purpose: For a single time-point hyperpolarized 13C magnetic resonance spectroscopyimaging (MRSI) of animal models, scan-time window after injecting substrates iscritical in terms of signal-to-noise ratio (SNR) of downstream metabolites. Prescansof time-resolved magnetic resonance spectroscopy (MRS) can be performed todetermine the scan-time window. In this study, based on two-site exchange model,protocol-specific simulation approaches were developed for 13C MRSI and the optimalscan-time window was determined to maximize the SNR of downstream metabolites. Materials and Methods: The arterial input function and conversion rate constantfrom injected substrates (pyruvate) to downstream metabolite (lactate) were precalibrated,based on pre-scans of time-resolved MRS. MRSI was simulated using twositeexchange model with considerations of scan parameters of MRSI. Optimal scantimewindow for mapping lactate was chosen from simulated lactate intensity maps. The performance was validated by multiple in vivo experiments of BALB/C nude micewith MDA-MB-231 breast tumor cells. As a comparison, MRSI were performed withother scan-time windows simply chosen from the lactate signal intensities of prescantime-resolved MRS. Results: The optimal scan timing for our animal models was determined bysimulation, and was found to be 15 s after injection of the pyruvate. Compared to thesimple approach, we observed that the lactate peak signal to noise ratio (PSNR) wasincreased by 230%. Conclusion: Optimal scan timing to measure downstream metabolites usinghyperpolarized 13C MRSI can be determined by the proposed protocol-specificsimulation approaches.

Dual Component Analysis for In Vivo T2* Decay of Hyperpolarized 13C Metabolites

조은해,이준성,이한솔,양승욱,최영숙,왕은경,송호택,김동현 대한자기공명의과학회 2017 Investigative Magnetic Resonance Imaging Vol.21 No.1

Purpose: To investigate the exchange and redistribution of hyperpolarized 13C metabolites between different pools by temporally analyzing the relative fraction of dual T2* components of hyperpolarized 13C metabolites. Materials and Methods: A dual exponential decay analysis of T2* is performed for [1-13C] pyruvate and [1-13C] lactate using nonspatially resolved dynamic 13C MR spectroscopy from mice brains with tumors (n = 3) and without (n = 4) tumors. The values of shorter and longer T2* components are explored when fitted from averaged spectrum and temporal variations of their fractions. Results: The T2* values were not significantly different between the tumor and control groups, but the fraction of longer T2* [1-13C] lactate components was more than 10% in the tumor group over that of the controls (P < 0.1). The fraction of shorter T2* components of [1-13C] pyruvate showed an increasing tendency while that of the [1-13C] lactate was decreasing over time. The slopes of the changing fraction were steeper for the tumor group than the controls, especially for lactate (P < 0.01). In both pyruvate and lactate, the fraction of the shorter T2* component was always greater than the longer T2* component over time. Conclusion: The exchange and redistribution of pyruvate and lactate between different pools was investigated by dual component analysis of the free induction decay signal from hyperpolarized 13C experiments. Tumor and control groups showed differences in their fractions rather than the values of longer and shorter T2* components. Fraction changing dynamics may provide an aspect for extravasation and membrane transport of pyruvate and lactate, and will be useful to determine the appropriate time window for acquisition of hyperpolarized 13C images.

남·여 대학생의 골다공증에 대한 지식정도와 건강신념 비교조사연구

강연주,김산아,김유리,배혜우,송윤정,왕은경,이민정,조은주,한진호,김수지 이화여자대학교 간호과학대학 2003 이화간호학회지 Vol.- No.37

A study whose subjects are male and female undergraduates in youth has been done to suggest the basic material for planning instructive program effective in preventing osteoporosis by measuring the degree of their knowledge of osteoporosis and their convictions in health. This study targeted male and female undergraduates who are in the university which lie in Seoul and Gyeonggi and agreed to participate in this study. The subjects of this study amounted to 270, male and female 135 respectively. This questionnaire was composed of total 78 questions including 12 questions as to general characteristics of undergraduates, 24 questions as to the knowledge of osteoporosis, and 42' questions as to convictions in health(Kim, Horan & Gendler 1991). This questionnaire was self-reported method and data were analyzed into real numbers, percentage, t-test and ANOVA, by operating SPSS and using Pearson correlation coefficient. The results of this study were summarized as follows: 1. Osteoporosis Knowledge, the degree of osteoporisis health belief 1) Knowledge of osteoporosis The mean of osteoporosis knowledge in male and female undergraduates who are in the university was 73.81 in range of 24 to 96 and by percent 76.89% about total score, showing a relatively middle-higher score than mean score. The mean of osteoporosis knowledge in female undergraduates who are in the university was 75.13 in range of 24 to 96 and by percent 78.25% about total score, showing a relatively middle-higher score than mean score. The mean of osteoporosis knowledge in male undergraduates who are in the university was 72.50 in range of 24 to 96 and by percent 75.52% about total score, showing a relatively middle-higher score than mean score. 2) The degree of osteoporisis health belief The mean of osteoporosis health belief in male and female undergraduates who are in the university variables that susceptibility 13.7, seriousness 15.57, benefits of exercise 21.54, benefits of calcium intake 21.22, barriers to exercise 14.79, barriers to calcium intake 13.26, motivation 17.29 in ever range of 6 to 30. The mean of benefits of exercise was highest in other variables and the mean of barriers to calcium intake was lowest in other variables. The mean of osteoporosis health belief in female undergraduates who are in the university variables that susceptibility 14.84, seriousness 16.24, benefits of exercise 21.57, benefits of calcium intake 21.37, barriers to exercise 15.84, barriers to calcium intake 13.47, motivation 17.04 in ever range of 6 to 30. The mean of benefits of exercise was highest in other variables and the mean of barriers to calcium intake was lowest in other variables. The mean of osteoporosis health belief in male undergraduates who are in the university variables that susceptibility 12.61, seriousness 14.90, benefits of exercise 21.50, benefits of calcium intake 21.07, barriers to exercise 13.73, barriers to calcium intake 13.04, motivation 17.55 in ever range of 6 to 30. The mean of benefits of exercise was highest in other variables and the mean of barriers to calcium intake was lowest in other variables. 2. Difference between male and female undergraduate in knowledge and health belief about osteoporosis according to general affection 1) Difference between male and female undergraduate in knowledge about osteoporosis according to general affection It is gender that seems to be similar correlation with knowledge about osteoporosis according to general affection. There were statistically higher figure in female undergraduate(F=2.943, p=O.OO4), by means of the mean of female undergraduate is 75.13, the mean of male undergraduate is 72.50, about osteoporosis knowledge according to gender. Especially, there were statistically similar difference (F=5.005, p<.OOl) in calcium knowledge of the prevention knowledge. In case of female, there weren't similar difference, but There were statistically similar difference (F=4.374, p=O.014) in female undergraduate in knowledge about osteoporosis according to age. There were shown higher age at the degree of higher knowledge. 2) difference between male and female undergraduate in health belief about osteoporosis according to general affection There were statistically similar difference according to age, drinking in all. of the male and female undergraduate in health belief about osteoporosis according to general affection. In case of female undergraduate, the difference of health belief about osteoporosis according to age is the benefit of calcium intake(F=6.008, p=O.OO3), and there were shown the highest score at age among 20 and 24, and the lowest score at age below. In case of male undergraduate, the statistically similar difference of health belief about osteoporosis according to age is the susceptibility(F=3.794, p=O.025), and there were shown the highest score at age below 19, and the lowest score at age above 25. In case of female undergraduate, the statistically similar difference of health belief about osteoporosis according to drink is the benefit of exercise(F=-1.990, p=0.049), and there were shown higher score at non-drinking experimental person than drinking. In case of male undergraduate, the statistically similar differences of health belief about osteoporosis according to drink are the benefit of exercise (F=-1.992, p=O.048) and calcium intake (F=-2.074, p=0.040), and there were shown higher score at non-drinking experimental person than drinking. In case of female undergraduate, the statistically similar differences of health belief about osteoporosis according to general affection are smoking and taking oral contraceptive pill. Smoking was shown statistically similar difference from susceptibility (F=2.237, p=0.027), and there were higher score at smoker than non-smoker. taking oral contraceptive pill was shown statistically similar difference from susceptibility(F=2.534, p=0.012), and there were higher score at taker than not. 0In case of male undergraduate, the statistically similar differences of health belief about osteoporosis according to general affection are the benefit of exercise and calcium intake according to start age for drinking. The start age for drinking was shown statistically similar difference from the benefit of exercise(F=4.555, p=0.OO5). There were higher score at the start age among 16-19 and lower score at the start age above 20. It was also shown statistically similar difference from the benefit of calcium intake(F=3.521, p=O.017). There were the highest score at the start age among 16-19 and the lowest score at the start age among 13-15. 3. The relationship between osteoporosis knowledge and osteoporosis health belief. There was statistically a significant positive correlation between osteoporosis knowledge and osteoporosis health belief(r=0.1761, p=O.OO4) of the osteoporosis health belief. There was statistically a significant positive correlation between osteoporosis knowledge and susceptibility(r=0.1384, p=O.023), benefits of exercise(r=0.1210, p=O.047), motivation (r=0.1413, p=O.021). There was statistically a significant positive correlation between osteoporosis knowledge and susceptibility, benefits of exercise, motivation of the osteoporosis health belief. In conclusion, the degree of osteoporosis knowledge in female undergraduate was significantly higher than male undergraduate, there was statistically a significant positive correlation between osteoporosis knowledge and susceptibility, benefit of exercise, motivation. And finally, approximal research according to distiction of sex might be needed to prevent effective osteoporosis. And this result shows that improving level of osteoporosis knowledge will be effective to promoting motivation and health behavior by increasing susceptibility and benefit of exercise.