• Investigative Magnetic Resonance Imaging
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• v.1 no.1
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• pp.135-141
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• 1997

Purpose: To assess the usefulness of breath-hold fast MR imaging of liver with fat suppression (FS) by application of chemical saturation technique in the diagnosis of regional fatty changes suspected in sonography. Materials and Methods: Thirteen patients who had focal lesions with diffuse, homogeneous signal changes after FS through chemical saturation technique without additional changes of imaging parameter during MR imaging of liver were selected. T1-weighted fast low-angle shot and T2-weighted turbo spin-echo sequences were obtained with or without FS during each single breath-holding session. Subjective changes of signal intensity between the pre-FS and the FS images were compared with the sonographic findings in each lesion. Results: Seven lesions of decreased signal intensity after FS on T1 or T2-weighted images, including three lesions only at FS T1 images, were regarded as focal fat infiltration. All seven lesions had compatible sonographic findings as homogenously echogenic areas. Another six lesions of subjectively increased signal intensity including two lesions only at FS T2 images were regarded as focal fat sparing. All six lesions had sonographic findings as homogenous echo poor areas suggesting focal fat sparing. In cases regarded as fat infiltration, score changes were more prominent at FS T1 images than FS T2 images(p=0.0002). In cases regarded as fat sparing, score changes were more prominent at FS T2 images than FS T1 images(p=0.042). Conclusion: Breath-hold fast T1 and T2-weighted MR imaging with and without chemical saturation pre-pulse may be sufficient for characterization of regional fatty changes in the differential diagnosis of focal hepatic lesion found at sonography.

• Journal of radiological science and technology
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• v.32 no.1
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• pp.95-99
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• 2009

The purpose of this research is to seek SPAIR's reversal time (TI) which satisfies two conditions ; maintaining the suppression ability of fat tissue and simultaneously minimizing the inhomogeneity of fat tissue in T2 high-speed spin echo 3.0T magnetic resonance image (MRI) of the brain, and to compare SPAIR with STIR which is fat-suppression technique. The reversal times (TI) of SPAIR protocol are set to 1/2, 1/3, 1/6 and 1/12 of SPAIR TR (420 msec), namely 210 msec (8 people), 140 msec (26 people), 70 msec (26 people) and 35 msec (18 people) and STIR TI is set with 250 msec (26 people). With these parameter sets, we acquired the axis direction 104 images of the brain. In ROI ($50\;mm^2$) of output image, signal intensities of the fatty tissue, the muscular tissue, and the background were measured and the CNRs of fatty tissue and the muscular tissue were calculated. The inhomogeneity of the fatty tissue is SD/mean, where SD is the standard deviation and 'mean' is a average fatty tissue signal. Consequently, SPAIR TI is determined on either 1/3 or 1/6 of TR (420 ms) ; 140 ms or 70 ms. Because the difference of statistics in fat-suppression ability and inhomogeneity of fatty tissue is very small (p < 0.001), Selecting 140 ms seems to be better choice for the image quality. Meanwhile, Comparing SPAIR (TI : 140 ms) with STIR, the fat-suppression is not able to be considered statistically (p < 0.252), but the image quality is able to be considered statistically (p < 0.01). In conclusion, SPAIR is better than STIR in the image quality.

• Journal of the Korean earth science society
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• v.36 no.1
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• pp.109-124
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• 2015

A novel approach, hybrid surface rainfall (KNU-HSR) technique developed by Kyungpook Natinal University, was utilized for improving the radar rainfall estimation. The KNU-HSR technique estimates radar rainfall at a 2D hybrid surface consistings of the lowest radar bins that is immune to ground clutter contaminations and significant beam blockage. Two HSR techniques, static and dynamic HSRs, were compared and evaluated in this study. Static HSR technique utilizes beam blockage map and ground clutter map to yield the hybrid surface whereas dynamic HSR technique additionally applies quality index map that are derived from the fuzzy logic algorithm for a quality control in real time. The performances of two HSRs were evaluated by correlation coefficient (CORR), total ratio (RATIO), mean bias (BIAS), normalized standard deviation (NSD), and mean relative error (MRE) for ten rain cases. Dynamic HSR (CORR=0.88, BIAS= $-0.24mm\;hr^{-1}$, NSD=0.41, MRE=37.6%) shows better performances than static HSR without correction of reflectivity calibration bias (CORR=0.87, BIAS= $-2.94mm\;hr^{-1}$, NSD=0.76, MRE=58.4%) for all skill scores. Dynamic HSR technique overestimates surface rainfall at near range whereas it underestimates rainfall at far ranges due to the effects of beam broadening and increasing the radar beam height. In terms of NSD and MRE, dynamic HSR shows the best results regardless of the distance from radar. Static HSR significantly overestimates a surface rainfall at weaker rainfall intensity. However, RATIO of dynamic HSR remains almost 1.0 for all ranges of rainfall intensity. After correcting system bias of reflectivity, NSD and MRE of dynamic HSR are improved by about 20 and 15%, respectively.

• Journal of Gastric Cancer
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• v.5 no.2
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• pp.120-126
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• 2005

Purpose: Endoscopic ultrasonography (EUS) is a useful imaging procedure for the diagnosis of submucosal tumors in the stomach. The present study investigated the EUS features of benign and malignant gastrointestinal stromal tumors(GISTs) and assessed differences between the two groups. Materials and Methods: Thirty patients with a GIST in the stomach were included in the study (23 benign and 7 malignant GISTs). We compared characteristic EUS findings (tumor size, location of tumor, regularity of the outer margin, echoheterogeneity, presence of cystic spaces, echogenic foci and mucosal ulceration) between benign and malignant GISTs. Results: Tumor sizes over 40 mm were observed in $85.7\%$ of the malignant and $8.7\%$ of the benign tumors (P=0.000). Intralesional cystic spaces were noted in $71.4\%$ of the malignant and $8.7\%$ of the benign tumors (P=0.003). The outer margin was irregular in $71.4\%$ of the malignant and $8.7\%$ of the benign tumors (P=0.014). $85.7\%$ of the malignant and $13.0\%$ of the benign tumors had an echo-heterogeneity in the tumor (P=0.001). The locations of tumor and the presence of echogenic foci or mucosal ulcerations were not different between the two groups. Conclusion: Tumor sizes over 40 mm, intralesional cystic spaces, irregular outer margins, and echo-heterogeneity in the tumor were significantly more frequent in malignant GISTs. EUS can provide informations in differentiating benign from malignant GISTs.

• Childhood Kidney Diseases
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• v.15 no.2
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• pp.163-171
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• 2011

Purpose : To evaluate the prevalence of vesicoureteral reflux (VUR) according to the timing of voiding cystourethrography (VCUG) in infantile urinary tract infection (UTI). Methods : The data of 134 infants (1-12 months) with renal cortical defect in $^{99m}Tc$-2, 3-dimercaptosuccinic acid ($^{99m}Tc$-DMSA) scan with a diagnosis of UTI in two hospitals from 2000 to 2010 were retrospectively analyzed. The VCUG was performed after 2 weeks from the diagnosis of UTI in Group I (n=68), and the VCUG was performed within 2 weeks from the diagnosis of UTI in Group II (n=66). Results : There were no significant differences between the two groups in the duration of fever, white blood cell count, C-reactive protein levels, and abnormalities in ultrasonography (P>0.05). There was no significant difference between the two groups in the prevelence of VUR, bilateral VUR, and severe VUR. VCUG-induced UTI was detected 16 (23.5%) of patients in whom the procedure was performed 2 weeks after the diagnosis, and none of VCUG-induced UTI occurred in those in whom the procedure was performed 2 weeks within the diagnosis. Conclusion : We conclude that the prevalence of VUR according to the timing of VCUG did not differ between the two groups in infantile UTI with renal cortical defect in DMSA scan. We also found that performing VCUG with antibiotics can decrease risk of VCUG-induced UTI.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.1-6
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• 2014

Purpose : $T_2{^*}$ relaxation time which includes susceptibility information represents unique feature of tissue. The objective of this study was to investigate $T_2{^*}$ relaxation times of the normal glandular tissue and fat of breast using a 3T MRI system. Materials and Methods: Seven-echo MR Images were acquired from 52 female subjects (age $49{\pm}12 $years; range, 25 to 75) using a three-dimensional (3D) gradient-echo sequence. Echo times were between 2.28 ms to 25.72 ms in 3.91 ms steps. Voxel-based $T_2{^*}$ relaxation times and $R_2{^*}$ relaxation rate maps were calculated by using the linear curve fitting for each subject. The 3D regions-of-interest (ROI) of the normal glandular tissue and fat were drawn on the longest echo-time image to obtain $T_2{^*}$ and $R_2{^*}$ values. Mean values of those parameters were calculated over all subjects. Results: The 3D ROI sizes were $4818{\pm}4679$ voxels and $1455{\pm}785$ voxels for the normal glandular tissue and fat, respectively. The mean $T_2{^*}$ values were $22.40{\pm}5.61ms$ and $36.36{\pm}8.77ms$ for normal glandular tissue and fat, respectively. The mean $R_2{^*}$ values were $0.0524{\pm}0.0134/ms$ and $0.0297{\pm}0.0069/ms$ for the normal glandular tissue and fat, respectively. Conclusion: $T_2{^*}$ and $R_2{^*}$ values were measured from human breast tissues. $T_2{^*}$ of the normal glandular tissue was shorter than that of fat. Measurement of $T_2{^*}$ relaxation time could be important to understand susceptibility effects in the breast cancer and the normal tissue.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.17-24
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• 2014

Purpose : To determine whether high-resolution contrast-enhanced three dimensional imaging with spoiled gradient-recalled sequence (HR-CE 3D-SPGR) plays a meaningful role in the assessment of intracranial vertebral artery (ICVA) and posterior inferior cerebellar artery (PICA) in lateral medullary infarction (LMI). Materials and Methods: Twenty-five patients confirmed with LMI were retrospectively enrolled with approval by the IRB of our institute, and 3T MRI with HR-CE 3D-SPGR and contrast-enhanced magnetic resonance angiography (CE-MRA) were performed. Two radiologists who were blinded to clinical information and other brain MR images including diffusion weighted image independently evaluated arterial lesions in ICVA and PICA. The demographic characteristics, the area of LMI and cerebellar involvement were analyzed and compared between patients with arterial lesion in ICVA only and patients with arterial lesions in both ICVA and PICA on HR-CE 3D-SPGR. Results: Twenty-two of twenty-five LMI patients had arterial lesions in ICVA or PICA on HR-CE 3D SPGR. However twelve arterial lesions in PICA were not shown on CE-MRA. Concurrent cerebellar involvement appeared more in LMI patients with arterial lesion in ICVA and PICA than those with arterial lesion in ICVA alone (p = 0.069). Conclusion: HR-CE 3D-SPGR can help evaluate arterial lesions in ICVA and PICA for LMI patients.

• 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.

• Journal of Embryo Transfer
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• v.20 no.3
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• pp.271-277
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• 2005

This study was undertaken to determine the normal appearance of the postpartum uterine involution. Postpartum changes in uterine shape, architecture, echogenicity and diameter were monitored with ultrasonography in 8 Cocker spaniel bitches. The excretory period of vaginal discharges in 8 normal bitches of uterine involution was finished completely at 23.20$\pm$2.77 days (Mean$\pm$SD) postpartum. The short axis shape of the uterus was varied from polygonal to circular. This lasted until 1600$\pm$2.12 days Postpartum, during which time the short axis uterine shape gradually changed to circular. Also, the long axis shape of the uterus was created a beaded appearance of the horns until 25.60$\pm$2.51 days postpartum. The uterine diameter was decreased not only in the placental sites from 24.20$\pm$2.06mm at 1 day to 13.18$\pm$0.84mm at 7 days postpartum, but also in the interplacental sites 14.26$\pm$2.22mm at 1 day, 9.81$\pm$0.7mm at 7 days postpartum. There was a general trend of decreasing uterine diameter, which occurred more rapidly at the placental sites. In conclusion, normal postpartum uterine involution in Cocker spainel bitches appeared to be completed around 68 days postpartum by gross findings such as vaginal discharges, and by ultrasongraphic findings, uterine shape and echogenicity.

• Land and Housing Review
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• v.2 no.2
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• pp.111-123
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• 2011

A Ubiquitous-Ecological City (U-Eco City) is the new urban paradigm integrated with ubiquitous-city (U-City) connecting the high-tech IT technology to the urvan space with the concept of the sustainable eco-city. As a U-Eco City is attempted for the first time domestically and internationally, there is insufficient discussions for its develoment goal, planned design proposal, technology and service element and others. Even if there are plans to build up it, policy and technology, service structuring business and others, it is difficult to assess how it would bring the efficacy. Therefore, the purpose of this study is to present the indicators system to assess a U-Eco City. The results of this study revealed the following; First, the conceptual framework, which was established to achieve sustainable urban quality, can be suggested by establishing its notion of the U-Eco City. The concept of a U-Eco City as established in this study suggests that the economic development in growth-oriented level has to be conducted not only quality of urban environment but also in terms of sustainable to consider the complex impact of various development; Secondly, the developed assessment system has heightened the completeness as the evaluation index through the attitude survey. As a result of questionnaire survey with the subject of specialists and interested party of this study, the urban qualitative aspect is formulated for the stability as a relatively important aspect. For the urban continuity aspect, society, environment and economy have all similar importance, but the environment element was shown to be highest. And finally, subject area was selected on the basis of the evaluation system and the analysis was made on the basis of the implementation design plan of the area. As a result of the assessment, safety and economy have shown to be high. This is indirectly indicated for the priority in economic growth driven development plan unlike the importance of environmental continuity obtained through the attitude survey. When planning on urban development, there is a need for supplementing the environment part and it has to present the connection plan between the economic growth and environmental continuity.