• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.4068-4074
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• 2011

The purpose of this study was to examine the usefulness of MR Breast perfusion image and time-signal intensity curve in patients diagnosed with breast cancer. We selected on 20 patients who were histologically diagnosed to have invasive ductal carcinoma (IDC) from March 2009 to December 2010. First, the Breast perfusion mapping image was reconstructed after obtaining the dynamic contrast enhancement image. The reconstructed image measured the slope, maximal relative enhancement, and time to peak on the detail including the lesion region, normal region, back ground region after obtaining the time-signal intensity curve. The lesion region and normal and slope of the back ground part were measured with the quantitive analytical method about the research and the average was compared and was analyze. In the qualitative analysis, the signal strength of each pixel was analyze with the macroscopic and being high it was low, the medium (2) performed the division of (a) by the three-point standard and the average was measured. The findings from the quantitative image analysis are the following: In the lesion region, the slope and maximal relative enhancement were the highestest among and the time to peak was the highestest in the back ground region. In the qualitative analysis, the breast perfusion image showed a diagnostic efficiency.

• Proceedings of the Korean Society of Medical Physics Conference
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• 2002.09a
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• pp.341-344
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• 2002

Neurodegenerative disorders, like Alzheimer's disease, are often accompanied by reduced brain perfusion (cerebral blood flow). Using the intrinsic magnetic properties of water, arterial spin labeling magnetic resonance imaging (ASLMRI) can map brain perfusion without injection of radioactive tracers or contrast agents. However, accuracy in measuring perfusion with ASL-MRI can be limited because of contributions to the signal from stationary spins and because of signal modulations due to transient magnetic field effects. The goal was to optimize ASL-MRI for perfusion measurements in the aging human brain, including brains with Alzheimer's disease. A new ASL-MRI sequence was designed and evaluated on phantom and humans. Image texture analysis was performed to test quantitatively improvements. Compared to other ASL-MRI methods, the newly designed sequence provided improved signal to noise ratio improved signal uniformity across slices, and thus, increased measurement reliability. This new ASL-MRI sequence should therefore provide improved measurements of regional changes of brain perfusion in normal aging and neurodegenerative disorders.

• Progress in Medical Physics
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• v.14 no.3
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• pp.203-210
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• 2003

PET (positron emission tomography) permits the investigation of physiological and biochemical processes in vivo. The accuracy of quantifying PET data is affected by its finite spatial resolution, which causes partial volume effects. In this study, we developed a method for partial volume correction using Hoffman phantom PET and MR data, and applied various FWHM (full width at half maximum) levels. We also applied this method to PET images of normal controls and tested for the possibility of clinical application. $^{18}$ F-PET Hoffman phantom images were co-registered to MR slices. The gray matter and white matter regions were then segmented into binary images. Each binary image was convolved by 4, 8, 12, 16 mm FWHM levels. These convolved images of gray and white matter were merged corresponding to the same level of FWHM. The original PET images were then divided by the convolved binary images voxel-by-voxel. These corrected PET images were multiplied by binary images. The corrected PET images were evaluated by analyzing regions of interests, which were drawn on the gray and white matter regions of the original MR image slices. We calculated the ratio of white to gray matter. We also applied this method to the PET images of normal controls. On analyzing the corrected PET images of Hoffman phantom, the ratios of the corrected images increased more than that of the uncorrected images. With the normal controls, the ratio of the corrected images increased more than that of the uncorrected images. The ratio increase of the corrected PET images was lower than that of the corrected phantom PET images. In conclusion, the method developed for partial volume correction in PET data may be clinically applied, although further study may be required for optimal correction.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.431-433
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• 1999

본 논문에서는 뇌의 자기공명(이하 MR로 줄임) 영상에서 양측 대뇌반구의 뇌백질과 뇌회백질의 추출에 관하여 연구하였다. MR 영상은 특정 장기에서 일정한 gray level 값을 유지하는 전산화단층촬영(이하 CT로 줄임) 영상과는 달리 사람마다 gray level 값이 다르며 한 사람에 대해서도 각 슬라이스에 따라 gray level 값이 다르므로 각 슬라이스별로 조직의 특성을 파악하여 백질과 회백질의 추출에 이용하였다. 먼저 뇌를 둘러싸고 있는 두피, 근육, 두개골과 함께 안구를 제거한 후 두 개강 내에 위치한 뇌간과 소뇌의 특성을 차례로 인식하여 대뇌반구로부터 분리한 후 제거하였다. 또한 추출된 대뇌의 영상으로부터 백질과 회백질의 체적을 구하고, 뇌신경게 진단방사선과 전문의의 manual 작업과 비교하여 본 논문에서 제시한 방법의 정확도를 검증하였다.

• Biomedical Science Letters
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• v.11 no.4
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• pp.555-559
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• 2005

Evaluate the triolein emulsion could disrupt the barriers and to suggest as an experimental model in blood-ocular barrier studies. Triolein emulsion was infused into the carotid artery in the experimental group ten cats. Normal saline was used in another the control group ten cats. Pre contrast and postcontrast T1-weighted MR images were obtained at 30 minutes and 3 hours after embolization. Signal intensities were evaluated in the anterior, posterior chamber and in the vitreus qualitatively and quantitatively. Postembolization 30 minutes MR images were not different from those of the control group. Postembolization 3 hour MR images demonstrated delayed contrast enhancement in the anterior chamber of the ipsilateral and contralateral eyeballs and in the posterior chamber of the ipsilateral eyeball. Delayed contrast enhancement of the posterior chamber of the ipsilateral eyeball was statistically significant (P<0.05). The present study demonstrated significant contrast enhancement in the posterior chamber with infusion of triolein emulsion and can be a model in blood-aqueous barrier studies.

• Investigative Magnetic Resonance Imaging
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• v.11 no.1
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• pp.54-57
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• 2007

Localized nodular synovitis of the knee joint is a rare benign tumorous condition, and should be differentially diagnosed with pigmented villonodular synovitis. We report a case of localized nodular synovitis in the knee that was noted to have a pedicle and characteristic findings on MR image.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.1
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• pp.27-31
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• 2013

Perfusion MR imaging is how to use exogenous and endogenous contrast agent. Exogenous perfusion MRI methods which are dynamic susceptibility contrast using $T2^*$ effect and dynamic contrast-enhanced using T1 weighted image after injection contrast media. An endogenous perfusion MRI method which is arterial spin labeling using arterial blood flow in body. In order to exam perfusion MRI in human, technical access are very important according to disease conditions. For instance, dynamic susceptibility contrast is used in patients with acute stroke because of short exam time, while dynamic susceptibility contrast or dynamic contrast enhancement provides the various perfusion information for patients with tumor, vascular stenosis. Arterial spin labeling is useful for children, women who are expected to be pregnant. In this regard, perfusion MR imaging is required to understanding, and the author would like to share information with clinical users

• Proceedings of the KSMRM Conference
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• 2002.11a
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• pp.47-49
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• 2002

At present, the trend of magnetic field strength in MRI system is dramatically changing. In early 70, the only low field (<0.5T) was developed. It was technically difficult to develop the high field system. At that time, people believed that the fine MR imaging could not be obtained in the high field MR system due to the magnetic susceptibility effect. However, 1.5T system was evolved at the end of 80, and used for clinical usage. Thus, it was proved that the signal to noise ratio (SNR) could be greatly contribute to enhance the image quality. And, the results of functional MRI and MR spectroscopy could be improved in the higher field MR system. So, 8T system was eventually developed in Ohio State University Hospital at the end of 90. Therefore, there is no doubt that the system with the ultra high magnetic field strength will be developed near future in 21 century.

• Communications for Statistical Applications and Methods
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• v.16 no.2
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• pp.277-286
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• 2009

Image registration is a process to establish the spatial correspondence between images of the same scene, which are acquired at different view points, at different times, or by different sensors. In this paper, we introduce a robust brain registration technique for correcting the difference between two temporal images by the different coordinate systems in MR and CT image obtained from the same patient. Two images are registered where this measure is minimized using a modified conditional entropy(MCE: Modified Conditional Entropy) computed from the joint histograms for the intensities of two given images, we conduct the rendering for visualization of 3D volume image.

• Imaging Science in Dentistry
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• v.36 no.1
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• pp.41-48
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• 2006

Purpose : To evaluate the reliability and clinical usefulness of ultrasonography in the temporomandibular joint (TMJ). Materials and Methods : Parasagittal and paracoronal 1.5 T MR images and 7.5 MHz ultrasonographs of 40 TMJs in 20 asymptomatic volunteers were obtained. Disc position using MR imaging was evaluated and the distance between the lateral surface of mandibular condyle and the articular capsule using MR image and ultrasonograph of 27 TMJs with normal disc position was measured and compared. Intraobserver and interobserver measurements reliability was evaluated by using interclass correlation coefficients (ICC) and measurement error. Also, the distance measured on ultrasonographs was compared, according to mouth position and disc postion. Results : The normal disc position was found in 27 of 40 asymptomatic joints. At the intraobserver reliability of measurement, ICC at the closed and open mouth position were 0.89 and 0.91. The measurement error was 0.4% and 0.5%. At the interobserver reliability, ICC at the closed and open mouth position were 0.92 and 0.81. The measurement error was 0.4% and 0.7%. At the TMJ with normal disc position, the distances between the lateral surface of mandibular condyle and the articular capsule measured on MR images and ultrasonographs were $2.0{\pm}0.7mm,\;1.8{\pm}0.5mm$, respectively (p<0.05). On the ultrasonographs, the distances at open mouth position were $1.2{\pm}0.5mm$ (p<0.05). At the TMJ with medially displaced disc, the distances at the closed and open mouth position were $1.3{\pm}0.3\;mm\;and\;0.9{\pm}0.2\;mm$ (p<0.05). Conclusion : The results suggest ultrasonography of TMJ is a reliable imaging technique for assessment of normal disc position.