• Journal of Biomedical Engineering Research
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• v.23 no.4
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• pp.269-279
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• 2002

When we inject a current into an electrically conducting subject such as a human body, voltage and current density distributions are formed inside the subject. The current density within the subject and injection current in the lead wires generate a magnetic field. This magnetic flux density within the subject distorts phase of spin-echo magnetic resonance images. In Magnetic Resonance Current Density Imaging (MRCDI) technique, we obtain internal magnetic flux density images and produce current density images from $\bigtriangledown{\times}B/\mu_\theta$. This internal information is used in Magnetic Resonance Electrical Impedance Tomography (MREIT) where we try to reconstruct a cross-sectional resistivity image of a subject. This paper describes numerical techniques of computing voltage. current density, and magnetic flux density within a subject due to an injection current. We use the Finite Element Method (FEM) and Biot-Savart law to calculate these variables from three-dimensional models with different internal resistivity distributions. The numerical analysis techniques described in this paper are used in the design of MRCDI experiments and also image reconstruction a1gorithms for MREIT.

• Investigative Magnetic Resonance Imaging
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• v.14 no.2
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• pp.139-144
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• 2010

Enteric duplications associated with the pancreas are especially uncommon, and the differential diagnosis of pancreatic duplication cysts is often difficult, and may be confused with various cystic lesions of the pancreas. We report a case of pancreatic duplication cyst; present the images and laboratory findings including cyst fluid tumor markers. MR and MRS findings enabled the detection of the location, contour, characteristics of cystic fluid and definition of tissue planes between the lesion and adjacent structures, providing useful information for an accurate surgical approach.

• Investigative Magnetic Resonance Imaging
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• v.12 no.2
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• pp.107-114
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• 2008

Purpose : The aim of this study is to determine possibility of application of in vivo proton ($^1H$) magnetic resonance spectroscopy (MRS) in distinguishing cystic mass arising around pancreas by comparison of in vivo MRS, in vitro MRS using 3T MR machine, based on nuclear magnetic resonance (NMR). Materials and Methods : We obtained spectra of in vivo MRS, in vitro MRS and NMR from abdominal mass arising around pancreas (mucinous cystic neoplasm=5, intraductal papillary mucin producing tumor=5, pseudocyst=1, and lymphangioma=1). We estimated existence of peak of in vivo MRS, and in vitro MRS concordant to that of NMR. We also evaluated differential peak for predicting specific disease. Results : Correlation of presence of peak with NMR showed showed sensitivity of 29.6%, specificity of 82.6% and accuracy of 67.7% on in vivo MRS (p = 0.096, McNemar test), sensitivity of 57.1% and specificity of 92.6% and accuracy of 82.3% on in vitro MRS (p = 0.362, McNemar test). The spectra of NMR for IPMT showed more frequent peaks at 3.5-4.0 ppm (p=0.026). Conclusion : Although chemical analysis, using NMR could be regarded as possible tool to differentiate cystic masses, in vivo and in vitro MRS need further technical evolution for clinical application.

• Investigative Magnetic Resonance Imaging
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• v.4 no.2
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• pp.128-135
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• 2000

Purpose : The aim of this study is to develope the Magnetic Resonance Spectroscopy(MRS) data processing S/W which plays an important role as a diagnostic tool in clinical field. Materials and methods : Post-processing software of MRS based on graphical user interface(GUI) under windows operating system of personal computer(PC) was developed using MATLAB(Mathwork, U.S.A.). This tool contains many functions to increase the quality of spectrum data such as DC correction, zero filling, line broadening, Gauss-Lorentzian filtering, phase correction, etc. And we obtained the normal human brain $^1H$ MRS data from parietal white matter, basal ganglia and occipital grey matter region using 1.5T Gyroscan ACS-NT R6 (philips, Amsterdam, Netherland) MRS package. The analysis of the MRS peaks were performed by obtaining the ratio of peak area. Results : The peak ratios of NAA/Cr, Cho/Cr, MI/Cr for the different MRS machines have a little different values. But these peak ratios were not significantly different between different echo time MRS peak ratios in the same machine (p<0.05). Conclusion : MRS post-processing S/W based on GUI using PC was developed and applied to the analysis of normal human brain $^1H$ MRS. This independent MRS processing job increases the performance and throughput of patient scan of main console. Finally, we suggest that the database for normal in-yivo human MRS data should be obtained before clinical applications.

• Natural Product Sciences
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• v.27 no.3
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• pp.201-207
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• 2021

We have previously reported that Acer tegmentosum extract, which is traditionally used in Korea to reduce alcohol-related liver injury, suppresses liver inflammation caused by excessive alcohol consumption and might improve metabolism. The active ingredient, 6-O-galloylsalidroside (GAL), was isolated from A. tegmentosum, and we hypothesized that GAL could provide desirable pharmacological benefits by ameliorating physiological conditions caused by alcohol abuse. Therefore, this study focused on whether GAL could ameliorate alcoholic fat accumulation and repair liver injury in mice. During chronic alcohol consumption plus binge feeding in mice, GAL was administered orally once per day for 11 days. Intrahepatic lipid accumulation was measured in vivo using a noninvasive method, ¹H magnetic resonance imaging, and confirmed by staining with hematoxylin and eosin and Oil Red O. The serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) were measured using a Konelab system, and the triglyceride content was measured in liver homogenates using an enzymatic peroxide assay. The results suggested that GAL alleviated alcohol-induced steatosis,e as indicated by decreased hepatic and serum triglyceride levels in ethanol-fed mice. GAL treatment also correlated with a decrease in the Cd36 mRNA expression, thus potentially inhibiting the development of alcoholic steatosis via the hepatic de novo lipogenesis pathway. Furthermore, treatment with GAL inhibited the expression of cytochrome P450 2E1 and attenuated hepatocellular damage, as reflected by a reduction in ALT and AST levels. These findings suggest that GAL extracted from A. tegmentosum has the potential to serve as a bioactive agent for the treatment of alcoholic fatty liver and liver damage.

• Korean Journal of Radiology
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• v.19 no.6
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• pp.1110-1118
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• 2018

Objective: To perform a meta-analysis to quantitatively assess functional magnetic resonance imaging (MRI) in the diagnosis of locally recurrent prostate cancer. Materials and Methods: A comprehensive search of the PubMed, Embase, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was conducted from January 1, 1995 to December 31, 2016. Diagnostic accuracy was quantitatively pooled for all studies by using hierarchical logistic regression modeling, including bivariate modeling and hierarchical summary receiver operating characteristic (HSROC) curves (AUCs). The Z test was used to determine whether adding functional MRI to T2-weighted imaging (T2WI) results in significantly increased diagnostic sensitivity and specificity. Results: Meta-analysis of 13 studies involving 826 patients who underwent radical prostatectomy showed a pooled sensitivity and specificity of 91%, and the AUC was 0.96. Meta-analysis of 7 studies involving 329 patients who underwent radiotherapy showed a pooled sensitivity of 80% and specificity of 81%, and the AUC was 0.88. Meta-analysis of 11 studies reporting 1669 sextant biopsies from patients who underwent radiotherapy showed a pooled sensitivity of 54% and specificity of 91%, and the AUC was 0.85. Sensitivity after radiotherapy was significantly higher when diffusion-weighted MRI data were combined with T2WI than when only T2WI results were used. This was true when meta-analysis was performed on a per-patient basis (p = 0.027) or per sextant biopsy (p = 0.046). A similar result was found when $^1H$-magnetic resonance spectroscopy ($^1H$-MRS) data were combined with T2WI and sextant biopsy was the unit of analysis (p = 0.036). Conclusion: Functional MRI data may not strengthen the ability of T2WI to detect locally recurrent prostate cancer in patients who have undergone radical prostatectomy. By contrast, diffusion-weight MRI and $^1H$-MRS data may improve the sensitivity of T2WI for patients who have undergone radiotherapy.

• Asian-Australasian Journal of Animal Sciences
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• v.29 no.2
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• pp.219-229
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• 2016

Fatty liver is a common metabolic disorder of dairy cows during the transition period. Historically, the diagnosis of fatty liver has involved liver biopsy, biochemical or histological examination of liver specimens, and ultrasonographic imaging of the liver. However, more convenient and noninvasive methods would be beneficial for the diagnosis of fatty liver in dairy cows. The plasma metabolic profiles of dairy cows with fatty liver and normal (control) cows were investigated to identify new biomarkers using $^1H$ nuclear magnetic resonance. Compared with the control group, the primary differences in the fatty liver group included increases in ${\beta}$-hydroxybutyric acid, acetone, glycine, valine, trimethylamine-N-oxide, citrulline, and isobutyrate, and decreases in alanine, asparagine, glucose, ${\gamma}$-aminobutyric acid glycerol, and creatinine. This analysis revealed a global profile of endogenous metabolites, which may present potential biomarkers for the diagnosis of fatty liver in dairy cows.

• Journal of Biomedical Engineering Research
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• v.31 no.6
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• pp.464-471
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• 2010

Compressed sensing can be used to reduce scan time or to enhance spatial resolution in MRI. It is now recognized that compressed sensing works well in reconstructing magnitude images if the sampling mask and the sparsifying transform are well chosen. Phase images also play important roles in MRI particularly in chemical shift imaging and magnetic resonance electrical impedance tomography (MREIT). We reconstruct MRI phase images using the compressed sensing technique. Through computer simulation and real MRI experiments, we reconstructed phase images using the compressed sensing technique and we compared them with the ones reconstructed by conventional Fourier reconstruction technique. As compared to conventional Fourier reconstruction with the same number of phase encoding steps, compressed sensing shows better performance in terms of mean squared phase error and edge preservation. We expect compressed sensing can be used to reduce the scan time or to enhance spatial resolution of MREIT.

• Investigative Magnetic Resonance Imaging
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• v.17 no.4
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• pp.259-266
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• 2013

Purpose : To investigate the blood pharmacokinetics and bio-distribution of DTPA-bis-amide (L3) Gd(III) complexes. Materials and Methods: The pharmacokinetics and bio-distribution of Gd $(L3)(H_2O){\cdot}nH_2O$ were investigated in Sprague-Dawley rats after intravenous administration at a dose of 0.1 mmol Gd/kg. The Gd content in the blood, various tissues, and organs was determined by ICP-AES. Blood pharmacokinetic parameters were calculated using a two-compartment model. Results: The half-lives of ${\alpha}$ phase and ${\beta}$ phase Gd $(L3)(H_2O){\cdot}nH_2O$ were $2.286{\pm}0.11$ min and $146.1{\pm}7.5$ min, respectively. The bio-distribution properties reveal that the complex is mainly excreted by the renal pathway, and possibly excreted by the hepatobiliary route. The concentration ratio of Gd (III) was significantly higher in the liver and spleen than in other organs, and small amounts of Gd (III) ion were detected in the blood or other tissues of rats only after 7 days of intravenous administration. Conclusion: The MRI contrast agent Gd $(L3)(H_2O){\cdot}nH_2O$ provides prolonged blood pool retention in the circulation and then clears rapidly with minimal accumulation of Gd(III) ions. The synthesis of gadolinium complexes with well-balanced lipophilicity and hydrophilicity shows promise for their further development as blood pool MRI contrast agents.

• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.86-93
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• 1997

Purpose: To assess the ability of in vivo H-1 MRS to determine the degree of malignancy and to characterize the histopathologic type of intracranial solid tumors. Materials and Methods: In vivo H-1 MR spectra of the pathologically-proven 81 intracranial soild tumors (low-grade glioma 17 cases, high-grade glioma 31 cases, lymphoma 9 cases, meningioma 8 cases, central neurocytoma 4 cases, medulloblastoma 3 cases, PNET 3 cases, metastasis 2 cases, others 4 cases) were analyzed. H-1 MR spectroscopy was performed on a 1.5T MR unit using PRESS sequence with a TR of 2000ms, a TE of 270 or 135ms and a voxel size of $2{\times}2{\times}2cm^3$ for all spectra. N-acetyl aspartate (NAA)/Creatine complex(Cr), Choline complex (Cho)/Cr, and lactate (Lac)/Cr ratios were measured on the peak heights of each resonance and compared among the different tumors. Results: All intracranial solid tumors demonstrated decreased NAA, elevated Cho and lactate, and variable Cr levels. All tumors showed increased Cho/Cr and Lac/Cr, whereas NAA/Cr level was decreased. Mean Cho/Cr and Lac/Cr ratios were significantly higher in high-grade gliomas than in low-grade gliomas. However, NAA/Cr ratio showed no significant difference between low-grade and high-grade gliomas. Very high Cho peaks were seen in lymphomas, meningiomas, medulloblastomas, and neurocytomas in addition to high-grade gliomas. Conclusion: H-1 MRS may be useful in differentiating between low-grade and high-grade gliomas, however cannot characterize the histologic types or subtypes of tumors.