• Investigative Magnetic Resonance Imaging
• /
• v.7 no.1
• /
• pp.22-30
• /
• 2003

Purpose : The efficacy of magnetic resonance imaging for evaluating coronary artery disease has been reported. In this study, we evaluated the usefulness of breath-hold segmented K-space cine MR imaging for evaluating the patency of coronary artery bypass grafts (CABG). Materials and Method s : Thirty eight patients with a total of 92 CABGs (36 internal thoracic arteries and 56 saphenous vein grafts) were evaluated using segmented K-space cardiac-gated fast gradient echo sequence (2D-FASTCARD) MR imaging. MR magnitude images were evaluated from the hard copies by two independent observers. A graft was defined as patent if it was seen as a bright small round area on at least two consecutive images throughout the cardiac cycle at a position consistent with the expected location for that graft. Results : MR images were obtained successfully for 23 patients (61%). The sagittal planes were most helpful in visualizing the cross-section of sapheneous vein bypass graft to left circumflex artery branch, whereas the transverse planes were used for identification of internal mammary artery grafts to left anterior descending coronary artery or its branch and identification of saphenous vein grafts to right coronary artery. Forty five grafts were visible using this MR technique, while the grafts were not visible on seven saphenous vein grafts and two internal mammary artery grafts. In two patients showing symptoms of myocardial ischemia, one or two bypass grafts were not visible. Imaging, perpendicular plane to a CABG was important to visualize the flow inside the CABG with maximum sensitivity. Conclusion : Evaluation of patency of the bypass graft was clinically feasible by 2D-FASTCARD MR imaging, whereas any invisible bypass grafts should be further studied by contrast-enhanced MR angiography or by conventional angiography for confirmation of abnormalities.

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

• Investigative Magnetic Resonance Imaging
• /
• v.12 no.2
• /
• pp.131-141
• /
• 2008

Purpose : To investigate the feasibility and accuracy of Proton Resonance Frequency (PRF) shift based magnetic resonance (MR) temperature mapping utilizing the self-developed center array-sequencing phase unwrapping (PU) method for non-invasive temperature monitoring. Materials and Methods : The computer simulation was done on the PU algorithm for performance evaluation before further application to MR thermometry. The MR experiments were conducted in two approaches namely PU experiment, and temperature mapping experiment based on the PU technique with all the image postprocessing implemented in MATLAB. A 1.5T MR scanner employing a knee coil with $T2^*$ GRE (Gradient Recalled Echo) pulse sequence were used throughout the experiments. Various subjects such as water phantom, orange, and agarose gel phantom were used for the assessment of the self-developed PU algorithm. The MR temperature mapping experiment was initially attempted on the agarose gel phantom only with the application of a custom-made thermoregulating water pump as the heating source. Heat was generated to the phantom via hot water circulation whilst temperature variation was observed with T-type thermocouple. The PU program was implemented on the reconstructed wrapped phase images prior to map the temperature distribution of subjects. As the temperature change is directly proportional to the phase difference map, the absolute temperature could be estimated from the summation of the computed temperature difference with the measured ambient temperature of subjects. Results : The PU technique successfully recovered and removed the phase wrapping artifacts on MR phase images with various subjects by producing a smooth and continuous phase map thus producing a more reliable temperature map. Conclusion : This work presented a rapid, and robust self-developed center array-sequencing PU algorithm feasible for the application of MR temperature mapping according to the PRF phase shift property.

• The Korean Journal of Nuclear Medicine
• /
• v.38 no.3
• /
• pp.241-252
• /
• 2004

Purpose: Population based structural and functional maps of the brain provide effective tools for the analysis and interpretation of complex and individually variable brain data. Brain MRI and PET standard templates and statistical probabilistic maps based on image data of Korean normal volunteers have been developed and probabilistic maps based on cytoarchitectonic data have been introduced. A quantification method using these data was developed for the objective assessment of regional intensity in the brain images. Materials and Methods: Age, gender and ethnic specific anatomical and functional brain templates based on MR and PET images of Korean normal volunteers were developed. Korean structural probabilistic maps for 89 brain regions and cytoarchitectonic probabilistic maps for 13 Brodmann areas were transformed onto the standard templates. Brain FDG PET and SPGR MR images of normal volunteers were spatially normalized onto the template of each modality and gender. Regional uptake of radiotracers in PET and gray matter concentration in MR images were then quantified by averaging (or summing) regional intensities weighted using the probabilistic maps of brain regions. Regionally specific effects of aging on glucose metabolism in cingulate cortex were also examined. Results: Quantification program could generate quantification results for single spatially normalized images per 20 seconds. Glucose metabolism change in cingulate gyrus was regionally specific: ratios of glucose metabolism in the rostral anterior cingulate vs. posterior cingulate and the caudal anterior cingulate vs. posterior cingulate were significantly decreased as the age increased. 'Rostral anterior'/'posterior' was decreased by 3.1% per decade of age ($P<10^{-11}$, r=0.81) and 'caudal anterior'/'posterior' was decreased by 1.7% ($P<10^{-8}$, r=0.72). Conclusion: Ethnic specific standard templates and probabilistic maps and quantification program developed in this study will be useful for the analysis of brain image of Korean people since the difference in shape of the hemispheres and the sulcal pattern of brain relative to age, gender, races, and diseases cannot be fully overcome by the nonlinear spatial normalization techniques.

• Korean Journal of Ecology and Environment
• /
• v.46 no.4
• /
• pp.561-569
• /
• 2013

This study examines locational environment factors that may affect the vegetation structure in the forests of Naejang National Park. To that end, we selected LAI (Leaf Area Index), diameter at breast height, and tree height as structural variables as well as altitude above sea level, gradient, slope direction, soil moisture, topographic location, and amount of solar radiation as locational environment factors, using the method of canonical correlation analysis in order to find out correlation between them. As to the simple correlation between the locational environment factors and structural variables, the correlation coefficient was relatively low (0.6). The values of LAI, measured along the ridge with higher altitudes, decreased as the soil moisture and solar radiation increased. However, LAI increased as the gradient increased and the slope direction faced the north (farther from the east). In respect of the diameter at breast height, the diameter decreased as the altitude and gradient increased. But the diameter increased as the moisture and solar radiation increased. The tree height decreased as the moisture increased and the site was closer to the ridge. These various correlations show a variety of locational environment factors in the national park, implying that the structural variables are affected by complex locational environment factors. This study conducted a canonical correlation analysis on locational environment factors which may affect the vegetation structure, and the result showed that LAI increased and tree height & diameter at breast height decreased as the solar radiation & moisture decreased and altitude increased. Although more factors that may affect vegetation structure (e.g. climate) should be taken into account, this study is significant in that the vegetation structure, which can adapt to more unfavorable conditions in terms of solar radiation, moisture, and higher altitudes, could be inferred in a statistical way. The results of this study, especially the locational environment factors based on DEM, can be used for assessing diversity of vegetation structure in a forest and for monitoring the structure in a national park on a regular basis so as to establish more effective maintenance plans of a park.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.15
• /
• pp.6521-6526
• /
• 2015

Background: This study aimed toanalyze the risk behavior for cervical cancer (CC) and the human papillomavirus (HPV) prevalence and resolution among women who received care through the private healthcare network of a municipality in southern Brazil. Materials and Methods: This descriptive and retrospective study was conducted with 25 women aged 20 to 59 years who received care through the private healthcare network and were treated at a specialty clinic in the period from January to December 2012 in a municipality in Northwest Parana, Southern Brazil. Data from medical records with cytological and HPV results were used. Following treatment, these women were followed-up and reassessed after 6 months. Data were statistically analyzed using the t-test and chi-squared test at a 5% significance level. Results: The mean age of the studied women was $27.8{\pm}7.75$ years old, and the majority were married, with paid employment and were non-smokers. The mean age at menarche was $13.0{\pm}0.50$ years old, and the mean age at first intercourse was $17.5{\pm}1.78$ years, with only 8.0% (2) initiating sexual activity at an age ${\leq}15$ years old. The majority had 1 to 2 children (60.0%), while 88.0% reported having had one sexual partner in their lifetime, and all the women were sexually active. A total of 68.0% used a hormonal contraceptive method. All the women had leukorrhea and pain and were infected by a single HPV type. Regarding the lesion grade, 80.0% showed high risk and 20.0% low risk. The most prevalent high-risk HPV strain was 16. Conclusions: These findings provide relevant information on HPV risk factors and infection, as well as the treatment and 6-month follow-up results, in economically and socially advantaged women with no traditional risk factors, corroborating previous reports that different risk factors may be described in different populations. Thus, this study reinforces the fact that even women without the traditional risk factors should undergo HPVmonitoring and assessment to determine the persistence of infection, promoting early diagnosis of the lesions presented and appropriate treatment to thus prevent the occurrence of CC.

• Journal of The Korean Society of Clinical Toxicology
• /
• v.4 no.1
• /
• pp.7-16
• /
• 2006

Purpose: As basic information of antioxidant treatments for the patient with paraquat intoxication, in human peripheral lymphocytes, the cytotoxicity of paraquat was measured, and to evaluate the antioxidant effect of vitamin C and deferoxamine against this cytotoxicity, malondialdehyde (MDA), superoxide dismutase (SOD) activity and total antioxidant status (TAS) were measured. Methods: From 10 healthy adults, after obtaining a consent, 20ml peripheral blood was collected. Experimental groups were divided to (1) control group, the group treated with an identical amount of saline, (2) P group: the group treated with paraquat only, (3) PV group: the group treated with paraquat followed by vitamin C 30 minutes later, (4) PD group: the group treated with paraquat followed by deferoxamine 30 minutes later, (5) PVD group: the group treated with paraquat followed by vitamin C 30 minutes later and subsequently deferoxamine one hour later, and (6) PDV group: the group treated with paraquat followed by deferoxamine 30 minutes later and subsequently vitamin C 1 hour later, and thus to total 6 groups. In each group, 10 samples of peripheral blood was assigned and $100{\mu}M\;paraquat,\;100{\mu}M$ vitamin C, and $100{\mu}M$ deferoxamine were used as reagent. Lymphocytes were isolated, cultured, and cytotoxicity was measured by the Microculture Tetrazolium method (MTT assay), MDA and SOD activity, and TAS concentration were measured. Results: In regard to the cytotoxicity measured in each group, their cytotoxicity was decreased in the group treated with antioxidants, in comparison with the group treated with paraquat only. In the cases that the order of the treatment of these two antioxidants was altered, viability in the PDV group $(1.077{\pm}0.121)$ was increased more that the PVD group $(0.888{\pm}0.152)$ statistically significantly (p=0.018). Concerning the amount of MDA, in comparison with the P group $(6.78{\pm}0.93{\mu}mol/L)$, after the treatment of each antioxidant, the concentration of MDA was decreased statistically significantly (p<0.05). In the group treated with two antioxidants together, in comparison with the group treated only with one antioxidant, the amount of MDA was increased statistically significantly $(PV:\;3.96{\pm}0.98{\mu}mol/L,\;PD:\;4.92{\pm}1.50{\mu}mol/L,\;PVD:\;3.22{\pm}0.83{\mu}mol/L,\;and\;PDV:\;3.42{\pm}0.95{\mu}mol/L,\;p=0.007)$. The concentration of SOD measured in the blood in each group after the administration of paraquat, in comparison with the control group, a pattern of the elevation of SOD activity and subsequent decrease was detected, however, it was not statistically significant. In the comparison of the groups treated with antioxidants, in comparison with the P group $(1419.9{\pm}265.9{\mu}mol/L)$, SOD activity was decreased statistically significantly in only the PDV group $(1176.4{\pm}238.9{\mu}mol/L)$ (p=0.017). In regard to TAS measured in each group, in comparison with the P group $(0.87{\pm}0.05{\mu}mol/L)$, in all groups treated with the antioxidants, the PV group was $1.00{\pm}0.03{\mu}mol/L$ (p=0.005), the PD group was $9.01{\pm}0.24{\mu}mol/L$ was $4.64{\pm}3.98{\mu}mol/L$ (P=0.005), and the PDV group was $9.41{\pm}0.27{\mu}mol/La$ (p=0.005), and thus total antioxidant activity was increased statistically significantly In a multiple comparison test, the PDV group showed the highest total antioxidant activity (p<0.0001). Conclusion: The result of the assessment of the antioxidant effect of vitamin C and deferoxamine on paraquat-induced cytotoxicity showed that in regard to cytotoxicity, SOD activity and TAS measurement, the best result was observed in the PDV group. Therefore, it was found that vitamin C and deferoxamine were effective antioxidants for the paraquat-induced cytotoxicity, and it suggests that the administration of deferoxamine followed by vitamin C may improve their antioxidant effect more.

• Economic and Environmental Geology
• /
• v.53 no.1
• /
• pp.33-43
• /
• 2020

CO₂ geological storage is currently considered as the most stable and effective technology for greenhouse gas reduction. The saline formations for CO₂ geological storage are generally located at a depth of more than 800 m where CO₂ can be stored in a supercritical state, and an extensive impermeable cap rock that prevents CO₂ leakage to the surface should be distributed above the saline formations. Trough analysis of seismic and well data, we identified the basalt flow structure for potential CO₂ storage where saline formation is overlain by basalt cap rock around PZ-1 exploration well in the Southern Continental Shelf of Korea. To evaluate CO₂ storage capacity of the saline formation, total porosity and CO₂ density are calculated based on well logging data of PZ-1 well. We constructed a 3D geological grid model with a certain size in the x, y and z axis directions for volume estimates of the saline formation, and performed a property modeling to assign total porosity to the geological grid. The estimated average CO₂ geological storage capacity evaluated by the U.S. DOE method for the saline formation covered by the basalt cap rock is 84.17 Mt of CO₂(ranges from 42.07 to 143.79 Mt of CO₂).

• Korean Journal of Ecology and Environment
• /
• v.53 no.3
• /
• pp.229-240
• /
• 2020

In this study, the results of fish assemblage survey for 16 reservoirs in the Yeongsan·Seomjin-River watershed were presented with fish assemblage characteristics analysis in relation to reservoir size. The survey method including number of sampling sites was followed the "Biomonitoring survey and assessment manual" of the Ministry of Environment/National Institute of Environmental Research (MOE/NIER), and the reservoirs were categorized as three size groups, small, medium or large reservoirs, based on the MOE/NIER as well. Total 13 family classified into 44 species were collected from 2018 (7 reservoirs) to 2019 (9 reservoirs), and the dominant and subdominant species were Hemiculter eigenmanni (Relative abundance, RA, 32.9%) and Lepomis macrochirus (RA, 31.4%), respectively. As a result of the analysis in relation to the reservoir size, the average (±standard deviation) number of species of the small, medium and large reservoirs were 11±2.9, 14.3±2.1, 22.7±0.6, respectively, which showed positive correlation with the reservoir size. Total 6 fish assemblage characteristics(number of species, number of individuals, richness index, herbivorous fish ratio, carnivorous fish ratio, exotic fish ratio) showed significant differences between the each reservoir size groups (P<0.05). As a result of cluster analysis, 16 reservoirs were clustered into 5 groups with 60% similarity, and the each reservoirs seems to be clustered depends on the distance from each other, watershed and their historical geology rather than size. These results are baseline information for the understanding of fish assemblage in Korean reservoirs, important for establishing management policy of reservoirs in the Yeongsan·Seomjin-River watershed.

• Journal of Chest Surgery
• /
• v.39 no.6 s.263
• /
• pp.449-455
• /
• 2006

Background: Female sex was known to be a risk factor for mortality after coronary bypass grafting (CABG), and women showed higher in-hospital mortality than men. Material and Method: Between 1992 and 1996, 147 consecutive patients (98 men and 49 women) undergoing CABG were included in the study. Most patients had undergone CABG with left internal thoracic artery and saphenous vein under cardiopulmonary bypass. We examined the influence of gender on survival after CABG and looked for risk factors for survival. Result: There was no in-hospital mortality in women, but 3 death (3.0%) in men. During the mean follow-up period of $138.5{\pm}23.0$ months, mortality was lower in women than in men (20.4% vs 44.9%, p=0.004), and the most common cause of death in women was chronic renal failure (40%). Survival in women at 1, 5, 10, and f4 years was 100%, $98.0{\pm}2.0%,\;81.2{\pm}5.6%,\;and\;78.4{\pm}6.1%$, respectively, which was better than in men (p=0.004). Although preoperative left ventricular ejection fraction was higher in women than in men, this did not affect early and long-term survival difference between two sexes (p=0.15). Risk factor for long-term survival in women was diabetes (p=0.033) and in men number of diseased coronary artery (p=0.006). Conclusion: Long-term survival after CABG was better in women than men. Risk factor for long-term survival in women was morbid disease rather than cardiac disease.