• 제목/요약/키워드: Diffusion tensor imaging

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연령과 체질량지수(BMI)에 따른 뇌 백질 부위의 정상인 확산텐서영상 비등방도에 대한 연구 (Fractional Anisotropy of Diffuse Tensor Imaging of Normal Subjects in the Regions of the Brain White Matter According to Age and Body Mass Index (BMI))

  • 정재범;곽종혁;김동현
    • 한국방사선학회논문지
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    • 제12권2호
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    • pp.253-260
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    • 2018
  • 비흡연자와 한국형 알코올 선별 검사법 (AUDIT-K)설문지 척도점수에 따라 적정음주군(10점 이하)을 연구대상으로 하여 뇌 백질의 손상 유무를 파악 할 수 있는 확산텐서영상을 검사하고 영상을 획득 한 후 Tract-Based Spatial Statics(TBSS)방법으로 뇌 백질 부위의 신경섬유로의 비등방도 FA(fractional anisotropy)값을 측정 분석한 결과 연령과 체질량지수(BMI)의 변인에 따른 뇌 백질 모든 영역에서 FA값은 통계적으로 유의하지 않았으며 본 연구의 결과 값으로 추측하자면 즉, 연령과 체질량지수(BMI)는 뇌 백질의 미세구조성 변화에 크게 영향을 미치지는 않는다고 할 수 있다.

경두개 자기자극과 확산텐서 신경섬유로 검사를 통한 대뇌 병변의 국소화: 증례보고 (Localization of Bilateral Hemisphere Lesion Using Combined Transcranial Magnetic Stimulation and Diffusion Tensor Imaging: Report of Two Cases)

  • 이형남;오영빈;김기욱;원유희;고명환;서정환;박성희
    • 대한근전도전기진단의학회지
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    • 제20권2호
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    • pp.106-111
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    • 2018
  • Transcranial magnetic stimulation (TMS) has been a gold standard for investigating central motor pathways in humans. Diffusion tensor imaging with fiber tractography (DTI FT) is known for its usefulness in detecting white matter lesion in vivo. We investigated the clinical usefulness of elucidating the integrity and continuity of corticospinal tract (CST) by combined use of TMS and DTI FT in this study. We report two cases who have presented with left hemiparesis and evaluated by both TMS and DTI FT; 10-year-old boy with Mitochondrial Encephalomyopathy with Lactic Acidosis and Stroke-like episode syndrome and 20-year-old woman with traumatic brain injury. Combined use of TMS and DTI FT successfully led to localize the brain lesion that might cause motor impairment in patients with abnormal signal intensities in MRI. The results of this study suggest that TMS and DTI FT might provide the detailed information between function and anatomy of the CST, complementarily.

Brain Mapping: From Anatomics to Informatics

  • Sun, Woong
    • Applied Microscopy
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    • 제46권4호
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    • pp.184-187
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    • 2016
  • Neuronal connectivity determines brain function. Therefore, understanding the full map of brain connectivity with functional annotations is one of the most desirable but challenging tasks in science. Current methods to achieve this goal are limited by the resolution of imaging tools and the field of view. Macroscale imaging tools (e.g., magnetic resonance imaging, diffusion tensor images, and positron emission tomography) are suitable for large-volume analysis, and the resolution of these methodologies is being improved by developing hardware and software systems. Microscale tools (e.g., serial electron microscopy and array tomography), on the other hand, are evolving to efficiently stack small volumes to expand the dimension of analysis. The advent of mesoscale tools (e.g., tissue clearing and single plane ilumination microscopy super-resolution imaging) has greatly contributed to filling in the gaps between macroscale and microscale data. To achieve anatomical maps with gene expression and neural connection tags as multimodal information hubs, much work on information analysis and processing is yet required. Once images are obtained, digitized, and cumulated, these large amounts of information should be analyzed with information processing tools. With this in mind, post-imaging processing with the aid of many advanced information processing tools (e.g., artificial intelligence-based image processing) is set to explode in the near future, and with that, anatomic problems will be transformed into informatics problems.

Multimodal neuroimaging in presurgical evaluation of childhood epilepsy

  • Jung, Da-Eun;Lee, Joon-Soo
    • Clinical and Experimental Pediatrics
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    • 제53권8호
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    • pp.779-785
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    • 2010
  • In pre-surgical evaluation of pediatric epilepsy, the combined use of multiple imaging modalities for precise localization of the epileptogenic focus is a worthwhile endeavor. Advanced neuroimaging by high field Magnetic resonance imaging (MRI), diffusion tensor images, and MR spectroscopy have the potential to identify subtle lesions. $^{18}F$-FDG positron emission tomography and single photon emission tomography provide visualization of metabolic alterations of the brain in the ictal and interictal states. These techniques may have localizing value for patients which exhibit normal MRI scans. Functional MRI is helpful for non-invasively identifying areas of eloquent cortex. These advances are improving our ability to noninvasively detect epileptogenic foci which have gone undetected in the past and whose accurate localization is crucial for a favorable outcome following surgical resection.

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
    • 대한자기공명의과학회:학술대회논문집
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    • 대한자기공명의과학회 2002년도 제7차 학술대회 초록집
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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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사회불안장애 환자의 얼굴 관련 영역을 잇는 갈고리다발 하부경로 : 예비연구 (The Uncinate Fasciculus Sub-Tract Connecting Face-Specific Regions in Patients with Social Anxiety Disorder : A Preliminary Study)

  • 강봉석;이윤지;이재연;최수희
    • 대한불안의학회지
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    • 제16권2호
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    • pp.106-112
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    • 2020
  • Objective : Social anxiety disorder (SAD) is characterized by fear of social threat and exhibits limbic hyper-reactivity toward social stimuli such as emotional faces. A previous study identified the uncinate fasciculus (UF) sub-tract as particularly related to facial memory. To explore the white matter tract relating to face-specific brain regions, we investigated the UF sub-tract in SAD. Methods : The diffusion tensor images of 22 patients with SAD and 20 healthy controls were analyzed with tractography. The UF sub-tract was delineated using the regions of interest of face patches in the anterior temporal lobe and the orbitofrontal cortex, and fractional anisotrophy (FA) and total number of streamlines (ST) were analyzed. We examined the group comparison of FA and ST of the UF sub-tract and correlations of FA and ST with the social anxiety symptoms such as the Liebowitz Social Anxiety Scale (LSAS), the Social Interaction Anxiety Scale (SIAS), the Social Phobia Scale (SPS) and the Fear of Negative Evaluation scale (FNE) in SAD. Results : There were no group differences in FA and ST of the UF sub-tract. However, negative correlations were observed between ST of the right UF sub-tract and severity of social anxiety symptoms (LSAS, rs=-0.480, p=0.024; SIAS, rs=-0.580, p=0.005; SPS, rs=-0.590, p=0.004; FNE, rs=-0.675, p=0.001) in patients with SAD. Conclusion : Although patients with SAD did not show quantitative abnormalities in the UF sub-tact connecting face-specific brain regions, this structure seems to play a role in the symptom severity of SAD.

Difference in Injury of the Corticospinal Tract and Spinothalamic Tract in Patients with Putaminal Hemorrhage

  • Jang, Sung Ho;Seo, Jeong Pyo
    • The Journal of Korean Physical Therapy
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    • 제31권6호
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    • pp.358-362
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    • 2019
  • Purpose: We investigated the difference in injury of the corticospinal tract (CST) and the spinothalamic tract (STT) in patients with putaminal hemorrhage, using diffusion tensor tractography (DTT). Methods: Thirty one consecutive patients with PH and 34 control subjects were recruited for this study. DTT scanning was performed at early stage of PH (7-63 days), and the CST and STT were reconstructed using the Functional Magnetic Resonance Imaging of Brain (FMRIB) Software Library program. Injury of the CST and STT was defined in terms of the configuration or abnormal DTT parameters was more than 2 standard deviations lower than that of normal control subjects. Results: Among 31 patients, all 31 patients (100%) had injury of the CTS, whereas 25 patients (80.6%) had injury of the STT: the incidence of CST injury was significantly higher than that of STT (p<0.05). In detail, 20 (64.5%) of 31 patients showed a discontinuation of the CST in the affected hemisphere; in contrast, 14 patients (45.2%) of 31 patients showed a discontinuation of the STT in the affected hemisphere. Regarding the FA value, 6 (19.4%) of 31 patients and 2 (6.4%) of 31 patients were found to have injury in the CST and STT, respectively. In terms of the fiber number, the same injury incidence was observed in 11 patients (35.5%) in both the CST and STT. Conclusion: The greater vulnerability of the CST appears to be ascribed to the anatomical characteristics; the CST is located anteriorly to the center of the putamen compared with the STT.

신경 손상과 전기 뇌 자극에 의한 흰쥐의 뇌 섬유 경로 변화에 대한 기계학습 판별 (Classification of Fiber Tracts Changed by Nerve Injury and Electrical Brain Stimulation Using Machine Learning Algorithm in the Rat Brain)

  • 손진훈;음영지;정재준;차명훈;이배환
    • 한국컴퓨터정보학회:학술대회논문집
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    • 한국컴퓨터정보학회 2021년도 제64차 하계학술대회논문집 29권2호
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    • pp.701-702
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    • 2021
  • The purpose of the study was to identify fiber changes induced by electrical stimulation of a certain neural substrate in the rat brain. In the stimulation group, the peripheral nerve was injured and the brain area associated to inhibit sensory information was electrically stimulated. There were sham and sham stimulation groups as controls. Then high-field diffusion tensor imaging (DTI) was acquired. 35 features were taken from the DTI measures from 7 different brain pathways. To compare the efficacy of the classification for 3 animal groups, the linear regression analysis (LDA) and the machine learning technique (MLP) were applied. It was found that the testing accuracy by MLP was about 77%, but that of accuracy by LDA was much higher than MLP. In conclusion, machine learning algorithm could be used to identify and predict the changes of the brain white matter in some situations. The limits of this study will be discussed.

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요천추 신경총에 대한 자기공명신경조영술의 역할: 주제 범위 문헌고찰 (Role of MR Neurography for Evaluation of the Lumbosacral Plexus: A Scoping Review)

  • 김선경;정준용
    • 대한영상의학회지
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    • 제83권6호
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    • pp.1273-1285
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    • 2022
  • 목적 자기공명신경조영술은 말초신경을 시각화하는 데 최적화된 영상 기법이다. 본 주제 범위 문 헌고찰에서는 요천추신경총에서 자기공명신경조영술의 프로토콜을 조사하고, 요추신경총 질환 환자에서 자기공명신경조영술의 임상적 이득에 대해 고찰하고자 한다. 대상과 방법 두 개의 의료 데이터베이스에서 2021년 9월까지 영문으로 출판된 논문에 대해 체계적 문헌검색을 수행하였다. 'Magnetic resonance Imaging', 'lumbosacral plexus', 'neurologic disease'를 포함하는 55편의 논문을 분석하였다. 결과 요천추신경총의 자기공명신경조영술은 말초 신경 질환의 분포 확인, 신경 주변 주사시 유도, 좌골신경통 환자에서는 척추외 원인 평가에 유용하였다. 혈관억제 기법이 적용된 3차원 단시간 반전회복 고속 스핀에코 영상이 주된 자기공명신경조영술 기법이었다. 결론 향후 요천추신경총의 자기공명신경조영술에 대한 기술적 성숙과 임상적 유용성에 대한 검증이 필요하다.