• Title/Summary/Keyword: MR Imaging

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Gliomatosis Cerebri : Clinical Features and Prognosis (대뇌 신경교종증 : 임상특징 및 예후에 관한 연구)

  • Jo, Dae-Chuol;Hwang, Jeong-Hyun;Sung, Joo-Kyung;Hwang, Sung-Kyu;Hamm, In-Suk;Park, Yeun-Mook;Byun, Seung-Yul;Kim, Seung-Lae
    • Journal of Korean Neurosurgical Society
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    • v.30 no.12
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    • pp.1399-1405
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    • 2001
  • Objectives : Gliomatosis cerebri is an uncommon primary brain tumor characterized by diffuse neoplastic proliferation of glial cells, with the preservation of the underlying cytoarchitecture. The aim of this study is to evaluate clinical features, outcome of surgical treatment and adjuvant therapy of gliomatosis cerebri. Methods : Between Jan. 1990 and Dec. 2000, 12 patients were diagnosed with gliomatosis cerebri based on characteristic radiological and histological findings. The patients' age ranged from 18 to 77(mean 44) years and the male to female ratio was 7 : 5. Nine patients underwent decompressive surgery and three, biopsy only. Postoperative radiation therapy was given in all cases except three. In addition to radiation therapy, four patients received chemotherapy. The mean duration of follow-up period was 18.8 months. Results : The most common presenting symptom were seizure and motor weakness. The mean duration of symptom was 5.9 months. There was 5 bilateral lesions and tumor involved corpus callosum in 5, basal ganglia-thalamus in 4, and brain stem in 2. There was no operative mortality but four patients died during the follow-up. The mean survival period for 11 patients was 20.5 months from the time of diagnosis. In univariate analysis, the lesion involving corpus callosum, basal ganglia-thalamus and brain stem correlated significantly with the short length of survival(p<0.05). Also, postoperative radiation as a adjuvant therapy prolonged the patient's survival(p<0.05). Conclusions : In the management of gliomatosis cerebri patients, early detection by MR imaging, active management of increased intracranial pressure, decompressive surgical removal and postoperative adjuvant therapy such as radiation is thought to be a good treatment modality.

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Evaluation of Automatic Image Segmentation for 3D Volume Measurement of Liver and Spleen Based on 3D Region-growing Algorithm using Animal Phantom (간과 비장의 체적을 구하기 위한 3차원 영역 확장 기반 자동 영상 분할 알고리즘의 동물팬텀을 이용한 성능검증)

  • Kim, Jin-Sung;Cho, June-Sik;Shin, Kyung-Sook;Kim, Jin-Hwan;Jeon, Ho-Sang;Cho, Gyu-Seong
    • Progress in Medical Physics
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    • v.19 no.3
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    • pp.178-185
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    • 2008
  • Living donor liver transplantation is increasingly performed as an alternative to cadaveric transplantation. Preoperative screening of the donor candidates is very important. The quality, size, and vascular and biliary anatomy of the liver are best assessed with magnetic resonance (MR) imaging or computed tomography (CT). In particular, the volume of the potential graft must be measured to ensure sufficient liver function after surgery. Preoperative liver segmentation has proved useful for measuring the graft volume before living donor liver transplantations in previous studies. In these studies, the liver segments were manually delineated on each image section. The delineated areas were multiplied by the section thickness to obtain volumes and summed to obtain the total volume of the liver segments. This process is tedious and time consuming. To compensate for this problem, automatic segmentation techniques have been proposed with multiplanar CT images. These methods involve the use of sequences of thresholding, morphologic operations (ie, mathematic operations, such as image dilation, erosion, opening, and closing, that are based on shape), and 3D region growing methods. These techniques are complex but require a few computation times. We made a phantom for volume measurement with pig and evaluated actual volume of spleen and liver of phantom. The results represent that our semiautomatic volume measurement algorithm shows a good accuracy and repeatability with actual volume of phantom and possibility for clinical use to assist physician as a measuring tool.

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Usefulness of Preoperative Breast MRI in Breast Cancer Diagnosed After Excisional Biopsy (유방 절제 생검 후 유방암이 진단된 환자에서 수술 전 자기공명영상의 유용성)

  • Wui, Jung-Hyun;Kang, Bong-Joo;Cha, Eun-Suk;Kim, Sung-Hun;Jung, Na-Young;Choi, Jae-Jeong
    • Investigative Magnetic Resonance Imaging
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    • v.12 no.2
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    • pp.161-169
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    • 2008
  • Purpose : The aim of this study was to evaluate the usefulness of MRI performed after excisional biopsy to diagnose residual cancer and additional lesions. Materials and Methods : A total of 16 patients who had breast cancer diagnosed by excisional biopsy underwent preoperative breast MRI between March 2005 and August 2007 were included. MRI findings were considered positive for residual cancer if focal, thick, or irregular rim enhancement or adjacent enhancing lesion was identified around the postoperative biopsy cavity. And additional lesions separated from biopsy cavity including multifocal, multicentric, or contralateral lesion were evaluated. We evaluated the diagnostic accuracy of MRI, comparing MRI with histopathologic finding, and the impact of MRI on surgical planning. Results : The sensitivity and specificity of MRI for detecting residual disease considering rim enhancement were 85.7%(6/7) and 55.6%(5/9). Additional lesions including multifocal, multicentric, or contralateral lesion were found in 6 patients. In 7 patients, results of MRI findings changed surgical treatment planning. Conclusion : The pattern of rim enhancement on MRI after excisional biopsy is not differential point to evaluate remnant lesion. But MRI has an important role to help the detection of multifocal or multicentric, or contralateral breast malignancies, resulting in beneficial change in surgical treatment planning.

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Implementation about measurement of the head SAR and variable parameter according to operation control mode in brain MR study with 1.5Tesia (1.57 BRAIN MRI검사에서의 작동제어모드를 통한 두부 SAR측정과 변화인자에 관한 고찰)

  • Lee, Kyu-Su;Sim, Hyun;Moon, Ji-Hoon;Oh, Jae-Cheol
    • Proceedings of the KIEE Conference
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    • 2007.04a
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    • pp.58-60
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    • 2007
  • Magnetic Resonance Imaging(MRI) has become a very widely used medical procedur e. Clo.sed and open systems are typically used with static magnetic fields at or below 2 Tesla. BWhole body SAR(specific absorbsion rate) is the value of SAR averaged over the entire body of the patient over any period of 15 minutes. Head SAR is the value of SAR averaged over the head of the patient for any period of 10 minutes. SAR is a measure of the absorption of electromagnetic energy in the body' (typically in watts per kilogram (W/kg)). The normal operating mode comprises values of head SAR not higher than 3 W/kg. The second level controlled operating mode comprises values higher than 3 W/kg. Current FDA guidance limits the SAR in the whole body. including the head to a range of 1.5 to 4.0 W/kg, depending on the patient's clinical condition. SAR, limit restrictions are incorporated in all MRI systems. and domestic' s guidance limits the SAR in a part body. including the head to 3.2w/kg and less. The purpose of this study is to evaluate on change of head SAR in using MRI pulse sequence and to check if exceed 3.2(w/kg) level in domestic a part exposure through measured head SAR. 23 patient's the average head SAR of pulse sequence is that T2WI sagittal is 0.5375. T2WI axial(FSE) is 0.4817, T1WI axial(SE) is, 0.8179. FLAIR axial is 0.4580. GRE axial is 0.0077, Diffusion is 0.0824w/kg. The head SAR exposed per patient was proved 2.3845w/kg less than the international standard. Coefficient of correlation for the relations body weight and SAR or for the relations ETL(echo train length) and SAR is 1 value. Coefficient of correlation for the relations between TR(time to repeat) and SAR is -0.602 value. so SAR increased relative to weight body and ETL. But the relations between TR and SAR is negative definite.

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Perfusion RRI of the Brain Using Oxygen Inhalation (산소 호흡을 이용한 뇌의 관류 자기공명영상)

  • 최순섭
    • Investigative Magnetic Resonance Imaging
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    • v.4 no.2
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    • pp.113-119
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    • 2000
  • Purpose : To know the possibility of clinical application of MRI using oxygen inhalation as a perfusion MRI Materials and methods : Two healthy volunteers and three patients of one moyamoya disease, one acute infarction and one meningioma were studied using a 1.5 Tesla MRI unit. Oxygen (15 liters/min) mixed with room air was given using face mask from 8 second to 35 second during the study. Images were acquired 25 times (scan time per study were 1.6 seconds) using susceptibility contrast EPI (echo planar image) sequence. Difference maps were acquired by early (study 12-18), and late (study 19-25) O2 inhalation image groups minus pre-O2 inhalation image group (study 3-9) with a Z-score of 0.7-1.0 using VB31C program of Magneton Vision. The resulting perfusion images were created by superimposition of difference maps on corresponding T1 weighted anatomic images. On moyamoya patient, similar perfusion images were acquired after Gd-DTPA injection, and compared with O2 inhalation perfusion images. Results ; The author can get the perfusion images of the brain by oxygen inhalation with susceptibility contrast EPI sequence at the volunteers, and the patient of moyomoya disease, acute infarction and meningioma. On moyamoya patient, perfusion images with O2 inhalation are similar with perfusion images by Gd-DTPA injection. Conclusion 1 This study has demonstrated that the susceptibility contrast EPI by oxygen inhalation can be used as the clinically useful perfusion MRI technique

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3-Dimensional Computed Tomography of Atlantoaxial Instability in Three Dogs (개에서 컴퓨터단층영상의 3차원 재구성을 통한 환축추골 아탈구 진단 3례)

  • Ahn, Se-Joon;Choi, Soo-Young;Lim, Soo-Ji;An, Ji-Young;Lee, In;Kwon, Young-Hang;Choi, Ho-Jung;Lee, Young-Won
    • Journal of Veterinary Clinics
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    • v.26 no.5
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    • pp.490-494
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    • 2009
  • A 2-year-old Maltese and a 5-month-old Yorkshire terrier were presented with ataxia. Tetraparesis was observed in a 9-year -old Yorkshire terrier. The localizations of the lesions suggested brain or cervical spinal cord by the neurological examination, and the following images was achieved: radiography, axial images of computed tomography (CT), reconstruction image of CT such as multi-planar reformation(MPR) and 3-dimensional(3D) reconstruction and magnetic resonance imaging (MRI). On radiography, the misalignment between atlas (C1) and axis (C2), absent dens of axis, and increased space between the dorsal arch of C1 and spinous process of C2 were found. The discontinuation between dens and body of C2 was identified through axial CT images, and the fragmentation of dens separated from axis was observed through MPR and 3D image in all case. The hyperintense lesions and the spinal cord compression on T2-weighted MR images were represented in a dog with tetraparesis, the others represented only spinal cord compression. Three dogs were diagnosed as atlantoaxial instability (AAI) by dens fracture of C2. The dog with tetraparesis was euthanized due to guarded prognosis. The others were recovered completely. It is difficult to differentiate dens fracture of C2 from abnormal dens such as agenesis and hypoplasia. We thought that CT is very useful to evaluate the dens of C2 and differentiate the causes of AAI, and the reconstruction images of CT such as MPR and 3D make the translation of the fragmented dens or axis of AAI more precisely evaluate.

Lumbar Herniated Disc Resorption of 78 Patients after Korean Medicine Treatment (요추 추간판 탈출증 환자 78명의 한방치료 후 디스크 재흡수 증례 보고)

  • Jung, Bum-Hwan;Jo, Joo-Hyun;Yoon, Yong-Il;Park, Sang-won;Kim, Sung-Moon;Go, Ung;Jung, Jin-soo;Kim, Jung-Hoon;Huh, Suk-Won;Kim, Ji-Won;Kim, Moon-Hwi
    • Journal of Korean Medicine Rehabilitation
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    • v.26 no.1
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    • pp.87-93
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    • 2016
  • Objectives To analyze the resorption of herniated lumbar intervertebral disc on MRI in patients who were treated with Korean Medicine. Methods 78 patients with lumbar disc herniation were included, 47 males and 32 females. Patients' diagnosis was based on magnetic resonance imaging (MRI). All of the patients were only treated with Korean Medicine for 6 months treatment, and underwent MRI examination twice, pre-treatment and post-treatment. MR images were assessed by reduction in diameter of T2-weighted image between pre-treatment and post-treatment, and analyzed by differences in sex, age and disc type. Results 91.2% (71 people) of total patients had extrusion type. Korean medicine treatment reduced lumbar disc herniation diameter of all the patients from 7.11 mm to 3.67 mm on average (p<0.001). The reduction of diameter in the male group was 3.52 mm on average. The reduction of diameter in the female group was 3.32 mm on average. The reduction of diameter was 3.28 mm in the group below age 29, 3.88 mm in the 30~39 age group, 3.39 mm in the 40~49 age group, and 2.71 mm in the above 50 age group on average. Conclusions The MRI results suggest that lumbar herniated disc can resorb with Korean Medicine treatment. The likelihood of lumbar disc resorption was higher at extrusion type. but there was not a significant difference between the sexes and between ages.

Preparation of Chitosan-coated Magnetite Nanoparticles (키토산이 피복된 나노 크기의 자성체 분말 제조)

  • Cho, Jun-Hee;Ko, Sang-Gil;Ahn, Yang-Kyu;Song, Ki-Chang;Choi, Eun-Jung
    • Journal of the Korean Magnetics Society
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    • v.16 no.1
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    • pp.102-106
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    • 2006
  • Magnetic nanoparticles can be used for a variety of biomedical applications. They can be used in the targeted delivery of therapeutic agents in vivo, in the hyperthermic treatment of cancers. in magnetic resonance (MR) imaging as contrast agents and in the biomagnetic separations of biomolecules. We have synthesized magnetite $(Fe_3O_4)$ nanoparticles using chemical coprecipitation technique with sodium oleate as surfactant. Nanoparticle size can be varied from 2 to 8nm by controlling the sodium oleate concentration. Magnetite phase nanoparticles could be observed from X-ray diffraction. Magnetic colloid suspensions containing particles with sodium oleate and chitosan have been prepared. Nanoparticles, both oleate-coated and chitosan-coated, have been characterized by several techniques. Atomic farce microscope (AFM) was used to image the coated nanoparticles. Magnetic hysteresis measurement were performed using a superconducting quantum interference device (SQUID) magnetometer at room temperature to investigate the magnetic properties of the magnetite nanoparticles. The SQUID measurements revealed superparamagnetism of nanoparticles.

Software development for the visualization of brain fiber tract by using 24-bit color coding in diffusion tensor image

  • Oh, Jung-Su;Song, In-Chan;Ik hwan Cho;Kim, Jong-Hyo;Chang, Kee-Hyun;Park, Kwang-Suk
    • Proceedings of the KSMRM Conference
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    • 2002.11a
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    • pp.133-133
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    • 2002
  • Purpose: The purpose of paper is to implement software to visualize brain fiber tract using a 24-bit color coding scheme and to test its feasibility. Materials and Methods: MR imaging was performed on GE 1.5 T Signa scanner. For diffusion tensor image, we used a single shot spin-echo EPI sequence with 7 non-colinear pulsed-field gradient directions: (x, y, z):(1,1,0),(-1,1,0),(1,0,1),(-1,0,1),(0,1,1),(0,1,-1) and without diffusion gradient. B-factor was 500 sec/$\textrm{mm}^2$. Acquisition parameters are as follows: TUTE=10000ms/99ms, FOV=240mm, matrix=128${\times}$128, slice thickness/gap=6mm/0mm, total slice number=30. Subjects consisted of 10 normal young volunteers (age:21∼26 yrs, 5 men, 5 women). All DTI images were smoothed with Gaussian kernel with the FWHM of 2 pixels. Color coding schemes for visualization of directional information was as follows. HSV(Hue, Saturation, Value) color system is appropriate for assigning RGB(Red, Green, and Blue) value for every different directions because of its volumetric directional expression. Each of HSV are assigned due to (r,$\theta$,${\Phi}$) in spherical coordinate. HSV calculated by this way can be transformed into RGB color system by general HSV to RGB conversion formula. Symmetry schemes: It is natural to code the antipodal direction to be same color(antipodal symmetry). So even with no symmetry scheme, the antipodal symmetry must be included. With no symmetry scheme, we can assign every different colors for every different orientation.(H =${\Phi}$, S=2$\theta$/$\pi$, V=λw, where λw is anisotropy). But that may assign very discontinuous color even between adjacent yokels. On the other hand, Full symmetry or absolute value scheme includes symmetry for 180$^{\circ}$ rotation about xy-plane of color coordinate (rotational symmetry) and for both hemisphere (mirror symmetry). In absolute value scheme, each of RGB value can be expressed as follows. R=λw|Vx|, G=λw|Vy|, B=λw|Vz|, where (Vx, Vy, Vz) is eigenvector corresponding to the largest eigenvalue of diffusion tensor. With applying full symmetry or absolute value scheme, we can get more continuous color coding at the expense of coding same color for symmetric direction. For better visualization of fiber tract directions, Gamma and brightness correction had done. All of these implementations were done on the IDL 5.4 platform.

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Effects of Gradient Switching Noise on ECD Source Localization with the EEG Data Simultaneously Recorded with MRI (MRI와 동시에 측정한 뇌전도 신호로 전류원 국지화를 할 때 경사자계 유발 잡음의 영향 분석)

  • Lee H. R.;Han J. Y.;Cho M. H.;Im C. H.;Jung H. K.;Lee S. Y.
    • Investigative Magnetic Resonance Imaging
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    • v.7 no.2
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    • pp.108-115
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    • 2003
  • Purpose : To evaluate the effect of the gradient switching noise on the ECD source localization with the EEG data recorded during the MRI scan. Materials and Methods : We have fabricated a spherical EEG phantom that emulates a human head on which multiple electrodes are attached. Inside the phantom, electric current dipole(ECD) sources are located to evaluate the source localization error. The EEG phantom was placed in the center of the whole-body 3.0 Tesla MRI magnet, and a sinusoidal current was fed to the ECD sources. With an MRI-compatible EEG measurement system, we recorded the multi channel electric potential signals during gradient echo single-shot EPI scans. To evaluate the effect of the gradient switching noise on the ECD source localization, we controlled the gradient noise level by changing the FOV of the EPI scan. With the measured potential signals, we have performed the ECD source localization. Results : The source localization error depends on the gradient switching noise level and the ECD source position. The gradient switching noise has much bigger negative effects on the source localization than the Gaussian noise. We have found that the ECD source localization works reasonably when the gradient switching noise power is smaller than $10\%$ of the EEG signal power. Conclusion : We think that the results of the present study can be used as a guideline to determine the degree of gradient switching noise suppression in EEG when the EEG data are to be used to enhance the performance of fMRI.

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