• Progress in Medical Physics
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• v.21 no.1
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• pp.35-41
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• 2010

The purpose of this study is to quantitate regional neurochemical profile of regional normal adult mice brain and assess regional metabolic differences by using ex vivo $^1H$ high-resolution magic angle spinning nuclear magnetic resonance spectroscopy ($^1H$ HR-MAS NMRS). The animals were matched in sex and age. The collected brain tissue included frontal cortex, temporal cortex, thalamus, and hippocampus. Quantitative 1D spectra were acquired on 40 samples with the CPMG pulse sequence (8 kHz spectral window, TR/TE = 5500/2.2 ms, NEX = 128, scan time: 17 min 20 sec). The mass of brain tissue and $D_2O$+TSP solvent were 8~14 mg and 7~13 mg. A total of 16 metabolites were quantified as follow: Acet, NAA, NAAG, tCr, Cr, tCho, Cho, GPC + PC, mIns, Lac, GABA, Glu, Gln, Tau and Ala. As a results, Acet, Cho, NAA, NAAG and mIns were showed significantly different aspects on frontal cortex, hippocampus, temporal cortex and thalamus respectively. The present study demonstrated that absolute metabolite concentrations were significantly different among four brain regions of adult mice. Our finding might be helpful to investigate brain metabolism of neuro-disease in animal model.

• Progress in Medical Physics
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• v.12 no.1
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• pp.31-39
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• 2001

NMR spectroscopy enables us to measure the molar concentration of the metabolites in the organisms, and this technique is the only method to measure the concentration non-invasively. The proton NMR spectroscopy has been used to study the biochemical changes in human as well as in animal brain. MRI uses the proton densities and its relaxation times for reconstructing images, but MRS gives the biochemical changes inside the body. NMR spectroscopy could provide the information which MRI and CT could not, and this makes NMR spectroscopy more useful in diagnosing diseases. This study was tried to develop the quantitation of the molar concentration of the metabolites in the brain using the proton MR spectroscopy. The spectra of each metabolites was obtained, and the proton MR spectra was obtained from the insula gray matter areas of the 16 volunteers. And this spectra was analyzed to estimated the molar concentrations of the metabolites in the region. The results showed the very similar to those of the others.

• 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.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 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.

• Investigative Magnetic Resonance Imaging
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• v.12 no.1
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• pp.8-19
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• 2008

Purpose : To investigate the 3-bond and spatial connectivity of human brain metabolites by scalar coupling and dipolar nuclear Overhauser effect/enhancement (NOE) interaction through 2D- correlation spectroscopy (COSY) and 2D- NOE spectroscopy (NOESY) techniques. Materials and Methods : All 2D experiments were performed on Bruker Avance 500 (11.8 T) with the zshield gradient triple resonance cryoprobe at 298 K. Human brain metabolites were prepared with 10% $D_2O$. Two-dimensional spectra with 2048 data points contains 320 free induction decay (FID) averaging. Repetition delay was 2 sec. The Top Spin 2.0 software was used for post-processing. Total 7 metabolites such as N-acetyl aspartate (NAA), creatine (Cr), choline (Cho), lutamine (Gln), glutamate (Glu), myo-inositol (Ins), and lactate (Lac) were included for major target metabolites. Results : Symmetrical 2D-COSY and 2D-NOESY pectra were successfully acquired: COSY cross peaks were observed in the only 1.0-4.5 ppm, however, NOESY cross peaks were observed in the 1.0-4.5 ppm and 7.9 ppm. From the result of the 2-D COSY data, cross peaks between the methyl protons ($CH_3$(3)) at 1.33 ppm and methine proton (CH(2)) at 4.11 ppm were observed in Lac. Cross peaks between the methylene protons (CH2(3,$H{\alpha}$)) at 2.50ppm and methylene protons ($CH_2$,(3,$H_B$)) at 2.70 ppm were observed in NAA. Cross peaks between the methine proton (CH(5)) at 3.27 ppm and the methine proton (CH(4,6)) at 3.59 ppm, between the methine proton (CH(1,3)) at 3.53 ppm and methine proton (CH(4,6)) at 3.59 ppm, and between the methine proton (CH(1,3)) at 3.53 ppm and methine proton (CH(2)) at 4.05 ppm were observed in Ins. From the result of 2-D NOESY data, cross peaks between the NH proton at 8.00 ppm and methyl protons ($CH_3$) were observed in NAA. Cross peaks between the methyl protons ($CH_3$(3)) at 1.33 ppm and methine proton (CH(2)) at 4.11 ppm were observed in Lac. Cross peaks between the methyl protons (CH3) at 3.03 ppm and methylene protons (CH2) at 3.93 ppm were observed in Cr. Cross peaks between the methylene protons ($CH_2$(3)) at 2.11 ppm and methylene protons ($CH_2$(4)) at 2.35 ppm, and between the methylene protons($CH_2$ (3)) at 2.11 ppm and methine proton (CH(2)) at 3.76 ppm were observed in Glu. Cross peaks between the methylene protons (CH2 (3)) at 2.14 ppm and methine proton (CH(2)) at 3.79 ppm were observed in Gln. Cross peaks between the methine proton (CH(5)) at 3.27 ppm and the methine proton (CH(4,6)) at 3.59 ppm, and between the methine proton (CH(1,3)) at 3.53 ppm and methine proton (CH(2)) at 4.05 ppm were observed in Ins. Conclusion : The present study demonstrated that in vitro 2D-COSY and NOESY represented the 3-bond and spatial connectivity of human brain metabolites by scalar coupling and dipolar NOE interaction. This study could aid in better understanding the interactions between human brain metabolites in vivo 2DCOSY study.

• Sleep Medicine and Psychophysiology
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• v.28 no.1
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• pp.18-26
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• 2021

Sleep is essential to brain function and mental health. Insomnia and obstructive sleep apnea (OSA) are the two most common sleep disorders, and are major public health concerns. Proton magnetic resonance spectroscopy (¹H-MRS) is a non-invasive method of quantifying neurometabolite concentrations. Therefore, ¹H-MRS studies on individuals with sleep disorders may enhance our understanding of the pathophysiology of these disorders. In this article, we reviewed ¹H-MRS studies in insomnia and OSA that reported changes in neurometabolite concentrations. Previous studies have consistently reported insomnia-related reductions in γ-aminobutyric acid (GABA) levels in the frontal and occipital regions, which suggest that changes in GABA are important to the etiology of insomnia. These results may support the hyperarousal theory that insomnia is associated with increased cognitive and physiological arousal. In addition, the severity of insomnia was associated with low glutamate and glutamine levels. Previous studies of OSA have consistently reported reduced N-acetylaspartate (NAA) levels in the frontal, parieto-occipital, and temporal regions. In addition, OSA was associated with increased myo-inositol levels. These results may provide evidence that intermittent hypoxia induced by OSA may result in neuronal damage in the brain, which can be related to neurocognitive dysfunction in patients with OSA. The current review summarizes findings related to neurochemical changes in insomnia and OSA. Future well-designed studies using ¹H-MRS have the potential to enhance our understanding of the pathophysiology of sleep disorders including insomnia and OSA.

• Journal of the Korean Society of Radiology
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• v.9 no.1
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• pp.47-53
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• 2015

Quantitative analysis of MR spectrum depending on mole concentration of the contrast media in cereberal metabolite phantom was performed. PRESS pulse sequence was used to obtain MR spectrum at 3.0T MRI system (Archieva, Philips Healthcare, Best, Netherland), and the phantom contains brain metabolites such as N-Acetyl Asparatate (NAA), Choline (Cho), Creatine (Cr) and Lactate (Lac). In this study, optimization of MRS PRESS pulse sequency depending on the concentration of contrast media (0, 0.1 and $0.3mmol/{\ell}$) was evaluated for various repetition time(TR; 1500, 1700 and 2000 ms). In control (cotrast-media-free) group, NAA and Cho signals were the highest at TR 2000 ms than at 1700 and 1500 ms. Cr had the highest peak signal at TR 1500 ms. When concentration of contrast media was $0.1mmol/{\ell}$, the metabolites were increased NAA 73%, Cho 249%, Cr 37% at TR 1700 ms compared with other TR, and also signal increased at $0.3mmol/{\ell}$, In $0.5mmol/{\ell}$ of contrast agent, cerebral metabolite peaks reduced, especially when TR 1500 ms and 2000 ms they decreased below those of control group. The ratio of metabolite peaks such as NAA/Cr and Cho/Cr decreased as the concentration of the contrast agent increased from 0.1 to $0.5mmol/{\ell}$. Authors found that the optimization of PRESS sequence for 0.3T MRS was as follows: low density of contrast agent ($0.1mmol/{\ell}$ and $0.3mmol/{\ell}$) made the highest signal intensity, while high density of contrast agent reveals the least reduction of signal intensity at 1700 ms. In conclusion, authors believe that it is helpful to reduce TR for acquiring maximum signal intensity.

• Investigative Magnetic Resonance Imaging
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• v.12 no.1
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• pp.20-26
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• 2008

Purpose : To present the T1 and T2 relaxation times of the major cerebral metabolites at 1.5T and 3.0T and compare those between 1.5T and 3.0T. Materials and Methods : Using the phantom containing N-acetyl aspartate (NAA), Choline (Cho), and Creatine (Cr) at both 1.5T and 3.0T MRI, the T1 relaxation times were calculated from the spectral data obtained with 5000 ms repetition time (TR), 20 ms echo time (TE), and 11 different mixing time (TM)s using STEAM (STimulated Echo-Acquisition Mode) method. The T2 relaxation times were obtained from the spectral data obtained with 3000 ms TR and 5 different TEs using PRESS (Point-RESolved Spectroscopy) method. The T1 and T2 relaxation times obtained at 1.5T were compared with those of 3.0T. Results : The T1 relaxation times of NAA were $2293\;{\pm}\;48\;ms$ at 1.5T and $2559\;{\pm}\;124\;ms$ at 3.0T (11.6% increase at 3.0T). The T1 relaxation times of Cho were $2540\;{\pm}\;57\;ms$ at 1.5T and $2644\;{\pm}\;76\;ms$ at 3.0T (4.1% increase at 3.0T). The T1 relaxation times of Cr were $2543\;{\pm}\;75\;ms$ at 1.5T and $2665\;{\pm}\;94\;ms$ at 3.0T (4.8% increase). The T2 relaxation times of NAA were $526\;{\pm}\;81\;ms$ at 1.5T and $468\;{\pm}\;74\;ms$ at 3.0T (11.0% decrease at 3.0T). The T2 relaxation times of Cho were $220\;{\pm}\;44ms$ at 1.5T and $182\;{\pm}\;35\;ms$ at 3.0T (17.3% decrease at 3.0T). The T2 relaxation times of Cr were $289\;{\pm}\;47\;ms$ at 1.5T and $275\;{\pm}\;57\;ms$ at 3.0T (4.8% decrease at 3.0T). Conclusion : The T1 relaxation times of the major cerebral metabolites (NAA, Cr, Cho), which were measured at the phantom, were 4.1%-11.6% longer at 3.0T than at 1.5T. The T2 relaxation times of them were 4.8%-17.3% shorter at 3.0T than at 1.5T. To optimize MR spectroscopy at 3.0T, TR should be lengthened and TE should be shortened.

• 월간산업보건
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• s.87
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• pp.17-22
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• 1995

심장질환과 뇌일혈은 미국에서의 중요한 사망원이다. 관상동맥질환의 위험인자들 - 가족력, 고혈압, 당뇨병, 지질대사 이상, 흡현 - 은 단지 이 질환의 일부분 만을 설명할 수 있다. 스트레스 또는 작업장이나 대기중에 존재하는 독성물질의 노출과 같은 인자들은, 그것의 위험정도에 대해서는 확실히 알려지지 않지만, 심장질환의 유발인자라고 생각된다. 이 장은 작업장내에 존재하는 여러가지 독성물질로 인한 심장혈관질환에 대하여 서술하였다.