• Progress in Medical Physics
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• v.11 no.1
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• pp.73-83
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• 2000

In this study, we investigate the effects of poor shimming on quantitative measurement of ratios of metabolite levels by proton magnetic resonance spectroscopy ($^1$H MRS). Coefficient of variation (COV) of metabolite ratios for point resolved spectroscopy (PRESS) and stimulated-echo acquisition mode (STEAM) spectra was evaluated from a phantom containing in vivo levels of metabolites using a conventional whole body 1.5T MR system and conventional acquisition and analysis protocol. A statistical P-value was also calculated from a linear regression for relationship of metabolite ratios. N-acetylaspartate (NAA)/ creatine (Cr) and NAA/ choline (Cho) had low COV values for the long and short TE spectra (29.1 and 27.5%; 23.8 and 12.6 %), whereas Cho/Cr and Cr/Cho had high COV values (50.0 and 68.6 %; 27.5 and 29.3 %). A linear relationship between NAA/Cr and Cho/Cr, and between NAA/Cho and Cr/Cho revealed the statistical significance in the long and short TE spectra, respectively (P < 0.0001 and P < 0.0001; P = 0.015 and P = 0.005). There was no significant relationship between Cho/NAA and Cr/NAA in the measurement (P = 0.159; P = 0.910). The present study suggested that NAA/Cr and NAA/Cho could be useful for data with poor shimming in $^1$H MR spectroscopy. In conclusion, statistical significance of metabolite ratios indicated that the Cr and Cho levels could be interpreted as a significant alteration factor in the long and short TE spectra, and then should be used with care to provide precise metabolite quantification.

• Journal of the Korean Society of Radiology
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• v.11 no.7
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• pp.589-595
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• 2017

This study evaluated the effect of gadolinium contrast agents on the spectrum of metabolites during $^1H-MRS$ of brain and to investigate whether the contrast agents injected before MR spectroscopy significantly affect the estimated peaks of MRS. From January to May 2017, brain MR spectroscopy was performed on 30 patients to compare the spectrum before and after contrast injection of the brain white matter tissue. As a result, the spectrum of metabolites decreased after the paramagnetic contrast agents injected. However, it was not statistically significant which indicated that the use of contrast agent did not meaningfully affect the spectrum of metabolites. In conclusion, the use of the paramagnetic contrast before the acquisition of the spectroscopy may aid voxel positioning especially when it is difficult to determine the exact location of the lesion or the contrast is low.

• Journal of Korean Neurosurgical Society
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• v.29 no.12
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• pp.1606-1611
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• 2000

Objective : To obtain more reliable sample in stereotactic biopsy, authors adopted proton chemical shift imaging ($^1H$-CSI)-directed biopsy. Until now, proton single voxel spectroscopy($^1H$-SVS) technique has been reported as a technique using metabolic information in stereotactic biopsy. The authors performed $^1H$-CSI with a stereotactic headframe in place and evaluated the pathologic results obtained from local metabolic information through $^1H$-CSI. Methods : $^1H$ CSI-directed stereotactic biopsy was performed in four patients. $^1H$-CSI and conventional Gd-enhancement stereotactic MRI was done simultaneously after application of the stereotatic frame. After reconstruction of metabolic maps of NAA/Cr, Cho/Cr, and Lactate/Cr ratios, the focal areas of increased Cho/Cr ratios and decreased NAA/Cr ratios were selected for target sites in the MR images Results : There was no difficulty in performing $^1H$-CSI with the stereotactic headframe in place. In pathologic examinations, the samples taken in area of increased Cho/Cr ratios and decreased NAA/Cr ratios showed the features of increased cellularity, mitoses and cellular atypism, thus facilitated the diagnosis. The pathologic samples taken from the area of increased Lactate/Cr ratios showed prominent feature of necrosis. Conclusion : $^1H$-CSI was feasible with stereotactic head frame in place. The final pathologic results obtained in our samples were concordant with the local metabolic informations from $^1H$-CSI. Authors believe that $^1H$ CSI-directed stereotactic biopsy may provide us advantages in obtaining more reliable tissue specimen in stereotactic biopsy.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.100-106
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• 2008

The purpose of this study was to confirm the exactitude of in vitro nuclear magnetic resonance spectroscopy(NMRS) and to complement the defect of in vivo NMRS. It has been difficult to understand the metabolism of a cerebellum using in vivo NMRS owing to the generated inhomogeneity of magnetic fields (B0 and B1 field) by the complexity of the cerebellum structure. Thus, this study tried to more exactly analyze the metabolism of a canine cerebellum using the cell extraction and high resolution NMRS. In order to conduct the absolute metabolic quantification in a canine cerebellum, the spectrum of our phantom included in various brain metabolites (i.e., NAA, Cr, Cho, Ins, Lac, GABA, Glu, Gln, Tau and Ala) was obtained. The canine cerebellum tissue was extracted using the methanol-chloroform water extraction (M/C extraction) and one group was filtered and the other group was not under extract processing. Finally, NMRS of a phantom solution and two extract solution (90% D2O) was progressed using a 500MHz (11.4 T) NMR machine. Filtering a solution of the tissue extract increased the signal to noise ratio (SNR). The metabolic concentrations of a canine cerebellum were more close to rat’s metabolic concentration than human’s metabolic concentration. The present study demonstrates the absolute quantification technique in vitro high resolution NMRS with tissue extraction as the method to accurately measure metabolite concentration.

• Journal of the Korean Society of Radiology
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• v.12 no.5
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• pp.623-630
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• 2018

Non-alcoholic fatty liver disease is the most common cause of chronic liver diseases. This study was to characterize early hepatic lipid changes in fatty liver rat model by in vivo short-echo time(TE) $^1H$-MRS(Proton - Magnetic Resonance Spectroscopy). Each the examinations were measured from liver parenchyma in rats at 0, 2, 4, 6, 8 weeks followed by high fat diet, respectively. Significant increase in lipid signals. 0.9, 1.3, 2.3, 2.8, and 5.3 ppm was found in animals with 2 weeks(p<0.01). Therefore, $^1H$-MRS is useful in detecting and characterizing various hepatic lipid alterations as early as 2 weeks for the start high fat diet.

• Journal of the Korean Society of Radiology
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• v.8 no.1
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• pp.35-42
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• 2014

The purpose of this study is to know the differences of metabolism in abnormal brain disease using a single-voxel proton MR spectroscopy(1H MRS) Together with five normal volunteers and each five patients with brain diseases, pathologically proved, underwent MRI and 1H MRS. The quantitative results of 1H MRS in adrenoleukodystrophy(ALD), hepatic encephalopathy(HE), and infarction gave unique information on the metabolite changes related with the white matter: the concentration of NAA decreased in all diseases; Cho, mI and Lac increased in ALD; Cho decreased in HE; and ${\beta}{\cdot}{\gamma}$-Glx and Lac increased in infarction. It is concluded that 1H MRS is capable of diagnosing brain diseases by monitoring metabolite changes in vivo that subsequently develope into abnormalities. 1H MRS may be a useful clinical tool for in both diagnosis and prognosis of brain diseases.

• Journal of the Mineralogical Society of Korea
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• v.13 no.4
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• pp.186-195
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• 2000

To study phosphate adsorption on kaolinite, $^{31}$ P MAS NMR(magic angle spinning nuclear magnetic resonance spectroscopy)has been used for kaolinite reacted in 0.1 M phosphate solutions at pH’s from 3 to 11. There are at least 3 different forms of phosphate on kaolinite. One is the phosphate physically adsorbed on kaolinite surface (outer-sphere complexes) or species left after vacuum-filtering. The second is the phosphate adsorbed by ligand exchange (inner-sphere complexes), and the third is Al-phosphate precipitates which are pH dependent. Most of the inner-spherer complexes and surface precipitates are mainly on hydroxided Al(aluminol) rather than hydroxided Si(silanol). These are pertinent with the results obtained from the phosphate adsorption experiments on silica gel and ${\gamma}$-Al$_2$O$_3$ as model compounds, respectively. The two peaks with more negative chemical shifts(more shielded) than the ortho-phosphate peak (positive chemical shift) are assigned to be the inner-sphere complexes and surface precipitates. The $^{31}$ P chemical shifts of the Al-phosphate precipitates are more negative than those of inner-sphere complexes at a given pH due to the larger number of P-O-Al linkages per tetrahedron. The chemical shifts of both the inner-sphere complexes and surface precipitates are more negative than those of inner-sphere complexes at a given pH due to the larger number of P-O-Al linkages per tetrahedron. The chemical shifts of both the inner-sphere complexes and surface precipitates become progressively less shielded with increasing pH. For the inner-sphere complexes, decreasing phosphate protonation combined with peak averaging by rapid proton exchange among phosphate tetrahedra with different numbers of protons is though to be the reason for the peak change. The decreasing shielding with increasing pH for surface precipitates is probably due to the decreasing average number of P-O-Al linkages per tetrahedron combined with decreasing protonation like inner-sphere complexes.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2003.09a
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• pp.73-73
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• 2003

Purpose: To determine the motor cortex dysfunction in hemiparetic patients due to deep intracerebral hematoma, authors performed proton magnetic resonance spectroscopy (lH MRS) for the evaluation of biochemical changes in the cortex on affected hemisphere according to axonal injury at the level of internal capsule. Methods: Ten control subjects and 14 patients with documentable hemiparesis of varying severity hemiparesis were included. All the hemiparesis was caused by deep intracerebral hematoma (putaminal and thalamic hemorrhage). In vivo 1H MRS study was performed on a 3T MRI/MRS system using STEAM sequence. As a single-voxel technique, Spectral parameters were: 20 ms TE, 2000 ms TR, 128 averages, 2500 Hz spectral width, and 2048 data points. Results: We found that the mean N-acetylaspartate (NAA)/phosphocreatine (Cr) and NAA/choline (Cho) ratios were significantly decreased in the motor cortex of the hemiparesis patients compared with control subjects. Conclusions: 1H MRS examinations of the motor cortex might help to differentiate distinct clinical entities of hemiparesis and to monitor pharmacological effects in therapeutic trials, providing a quantitative biological marker for motor neuron dysfunction. Acknowledgement: This study was supported by a grant of the Center for Functional and Metabolic Imaging Technology, Ministry of Health & Welfare, Republic of Korea. (02-PJ3-PG6-EV07-000).

• Korean Journal of Food Science and Technology
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• v.36 no.4
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• pp.643-647
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• 2004

Natural antimicrobial substance from peanut (Arachis hypogaea) shells was isolated and structurally elucidated. Peanut shells were extracted with methanol (MeOH) and concentrated in vacuo, MeOH extract was solvent-fractionated with ethyl acetate (EtOAc) and various buffer to obtain EtOAc acidic, neutral, and phenolic fractions. EtOAc neutral fraction, which showed antimicrobial activity, was purified through silica gel adsorption column, Sephadex LH-20 column, ODS column, and high performance liquid chromatographies, and its active substance was isolated and identified as pratensein (3',5,7-trihydroxy-4'-methoxyisoflavone) by spectroscopic methods of proton-nuclear magnetic resonance, mass spectrometry, and nuclear overhauser enhancement spectroscopy.

• Journal of the Korean Applied Science and Technology
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• v.15 no.4
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• pp.45-56
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• 1998

Methyl fructoside oleic acid polyester(MFPE), fructose-based sugar polyester, was synthesized by solvent-free, soap-free transesterification of methyl oleate with methyl fructoside(MF) as a sugar starting material in the presence of conventional potassium carbonate basic catalyst. Methyl fructoside was found to be an effective sugar starting material, because of its low softning point, high heat stability, high miscibility, and high reactivity than other sugars. Yield 98% of purified MFPE based on initial weight of MF was obtained at 1:5 of the molar ratio of methyl fructoside to methyl oleate, 2%(w/w) of potassium carbonate catalyst content, 20${\sim}$200mmHg of reduced pressure and $180^{\circ}C$ of reaction temperature. MFPE structure was confirmed by infrared and proton nuclear magnetic resonance spectroscopy. Physical properties of methyl of fructoside oleic acid polyester such as viscosity, HLB, solubility, color, refractive index, specific gravity, and density were similar to physical properties of sucrose polyesters(SPE) and vegetable oils. Then, it was elucidated that MFPE was sufficient to replace the SPE and conventional oils.