• Title/Summary/Keyword: MR Diffusion

Search Result 169, Processing Time 0.02 seconds

Diffusion Tensor Imaging in Nocturnal Frontal Lobe Epilepsy

  • Son, Chul-Ho;Woo, Sung-Gu;Cho, Yong-Won;Lee, Hyung;Han, Bong-Soo
    • Proceedings of the KSMRM Conference
    • /
    • 2002.11a
    • /
    • pp.84-84
    • /
    • 2002
  • 목적: 야간성 전두협 발작 (Nocturnal frontal lobe epilepsy NFLE)은 임상적으로 특징적인 야간성 운동성 발작으로 잘 알려져 있지만 일반적인 MR 영상에서는 대부분에서는 특이한 소견을 보이지 않아 확산 텐서 영상 (DTI)에서의 이상 소견 발현 유무를 알아보고자 한다. 대상 및 방법: 임상적 소견과, EEG 소견으로 진단된 NFLE 환자 6명을 대상으로 DTI 영상을 촬영하였다. 남자 2명, 여자 4명으로 평균연령은 32세 이었다. DTI영상은 single shot spin echo EPI 펄스 열을 사용하였고 사용한 영상 변수는 b value는 0, 1000 s/$\textrm{mm}^2$, TR 10000 msec, TE 71.8/72.3 msec, matrix 128$\times$128 (256 reconstruction), FOV 23cm, 5mm thickness, 2mm interstice gap, NEX 1. 19 slices, time은 4min 21sec (25방향) 이었다. 대조군으로 정상 성인 10명 (평균연령 31세)에서 동일한 방법으로 DTI 영상을 시행하여 분할 비등방도 (fractional anisotropy) 영상을 얻고 전두엽 백질에서 분할 비등방도 값을 측정하여 NFLE 환자군과 비교하였다.

  • PDF

High b-value Diffusion Study of Normal Brain at 3 Tesla

  • 이영주;손철호;황문정;배성진;장용민
    • Proceedings of the KSMRM Conference
    • /
    • 2002.11a
    • /
    • pp.83-83
    • /
    • 2002
  • 목적: 현재 임상적으로 사용되고 있는 확산경사자장의 세기 이상( > 1200)의 강한 확산 경사자장이 가해진 경우 뇌구조물들의 확산계수값을 조사하고 고자장(Bo = 3T)에서 이러한 강한 확산 경사자장을 이용하는 경우 1.5T에서 시행하는 경우와의 차이점을 비교 연구해보고자 하였다. 대상 및 방법: 정상 성인 3명을 대상으로 b-value를 0부터 3500까지 변화시키며 확산강조영상을 최대경사자장 40 mT/m, slew rate 150 T/m/s의 경사자장계가 장착된 3T MR scanner (General Electric, USA)에서 획득하였다. 사용한 펄스열은 Stejskal-Tanner type의 확산강조 경사자장이 포함된 single-shot SE EPI를 사용하였으며 영상획득시 사용한 파라미터는 다음과 같다. TR/TE= 10000/95.1, Thickness/space=512mm, FOV=24$\times$21cm, Matrix=128$\times$128, NEX=1 뇌구조물들에 관심 영역을 설정하고 b-value에 따른 신호감소를 측정하였다. 측정된 데이터를 hi-exponential decay 모델을 이용하여 분석하였다.

  • PDF

Evaluation of Quantitative Effectiveness of MR-DTI Analysis with and without Functional MRI (기능적 자기공명영상 사용유무에 따른 확산텐서영상 분석의 유효성 평가)

  • Lee, Dong-Hoon;Park, Ji-Won;Hong, Cheol-Pyo
    • The Journal of Korean Physical Therapy
    • /
    • v.25 no.5
    • /
    • pp.260-265
    • /
    • 2013
  • Purpose: This study was conducted in order to evaluate the quantitative effectiveness of region of interest (ROI) setting in MR-DTI analysis with and without fMRI activation results. Methods: Ten right-handed normal volunteers participated in this study. DTI and fMRI datasets for each subject were obtained using a 1.5T MRI system. For neural fiber tracking, ROIs were drawn using two methods: The drawing points were located in the fMRI activation areas or areas randomly selected by users. In this study, the neural fiber tract targeted the corticospinal tract (CST) Quantitative analyses were performed and compared. The pixel numbers passing through the fiber tract in the individual brain volume were counted. The ratios between the ROI pixel numbers and the extracted fiber pixel numbers, and the ratios between the fiber pixel numbers and the whole-brain pixel numbers were also calculated. Results: According to our results, extracted CST fiber tract in which the ROI was drawn with fMRI activation areas showed higher distribution than drawing the ROI by users' hands. In addition, the quantitatively measured values represented higher pixel distribution: The counted average pixel numbers were 4553.8 and 1943.3. The average ratios of the ROI areas were 33.87 and 22.52. The average percentages of the individual whole-brain volume numbers were 2.06 and 0.87. Conclusion: Results of this study appear to indicate that use of this method can allow for more objectives and significant for study of the recovery of neural fiber mechanisms and brain rehabilitation.

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

  • Seon Gyeong Kim;Joon-Yong Jung
    • Journal of the Korean Society of Radiology
    • /
    • v.83 no.6
    • /
    • pp.1273-1285
    • /
    • 2022
  • Purpose MR neurography (MRN) is an imaging technique optimized to visualize the peripheral nerves. This review aimed to discover an optimized protocol for MRN of the lumbosacral plexus (LSP) and identify evidence for the clinical benefit of lumbosacral plexopathies. Materials and Methods We performed a systematic search of the two medical databases until September 2021. 'Magnetic resonance imaging', 'lumbosacral plexus', 'neurologic disease', or equivalent terms were used to search the literature. We extracted information on indications, MRN protocols for LSP, and clinical efficacy from 55 studies among those searched. Results MRN of the LSP is useful for displaying the distribution of peripheral nerve disease, guiding perineural injections, and assessing extraspinal causes of sciatica. Three-dimensional short-tau inversion recovery turbo spin-echo combined with vascular suppression is the mainstay of MRN. Conclusion Future work on the MRN of LSP should be directed to technical maturation and clinical validation of efficacy.

Detecting Peripheral Nerves in the Elbow using Three-Dimensional Diffusion-Weighted PSIF Sequences: a Feasibility Pilot Study

  • Na, Domin;Ryu, Jaeil;Hong, Suk-Joo;Hong, Sun Hwa;Yoon, Min A;Ahn, Kyung-Sik;Kang, Chang Ho;Kim, Baek Hyun
    • Investigative Magnetic Resonance Imaging
    • /
    • v.20 no.2
    • /
    • pp.81-87
    • /
    • 2016
  • Purpose: To analyze the feasibility of three-dimensional (3D) diffusion-weighted (DW) PSIF (reversed FISP [fast imaging with steady-state free precession]) sequence in order to evaluate peripheral nerves in the elbow. Materials and Methods: Ten normal, asymptomatic volunteers were enrolled (6 men, 4 women, mean age 27.9 years). The following sequences of magnetic resonance images (MRI) of the elbow were obtained using a 3.0-T machine: 3D DW PSIF, 3D T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) with SPAIR (spectral adiabatic inversion recovery) and 2D T2 TSE (turbo spin echo) with modified Dixon (m-Dixon) sequence. Two observers used a 5-point grading system to analyze the image quality of the ulnar, median, and radial nerves. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of each nerve were measured. We compared 3D DW PSIF images with other sequences using the Wilcoxon-signed rank test and Friedman test. Inter-observer agreement was measured using intraclass correlation coefficient (ICC) analysis. Results: The mean 5-point scores of radial, median, and ulnar nerves in 3D DW PSIF (3.9/4.2/4.5, respectively) were higher than those in 3D T2 SPACE SPAIR (1.9/2.8/2.8) and 2D T2 TSE m-Dixon (1.7/2.8/2.9) sequences (P < 0.05). The mean SNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR, but there was no difference between 3D DW PSIF and 2D T2 TSE m-Dixon in all of the three nerves. The mean CNR in 3D DW PSIF was lower than 3D T2 SPACE SPAIR and 2D T2 TSE m-Dixon in the median and ulnar nerves, but no difference among the three sequences in the radial nerve. Conclusion: The three-dimensional DW PSIF sequence may be feasible to evaluate the peripheral nerves around the elbow in MR imaging. However, further optimization of the image quality (SNR, CNR) is required.

Software Development for the Visualization of the Orientation of Brain Fiber Tracts in Diffusion Tensor Imaging Using a 24 bit Color Coding

  • Jung-Su Oh;In Chan Song;Ik-Hwan Cho;Jong-Hyo Kim;Kee Hyun Chang;Kwang-Suk Park
    • Journal of Biomedical Engineering Research
    • /
    • v.25 no.1
    • /
    • pp.43-47
    • /
    • 2004
  • Interests in human brain functionality and its connectivity have much frown up. DTI (Diffusion tensor imaging) has been known as a non-invasive MR) technique capable of providing information on water diffusion in tissues and the organization of white matter tract. Thus. It can provide us the information on the direction of brain fiber tract and the connectivity among many important cortical regions which can not be examined by other anatomical or functional MRI techniques. In this study. was used the 24 bit color coding scheme on the IDL platform in the windows environment to visualize the orientation of major fiber tracts of brain such as main association, projection, commissural fibers and corticospinal tracts. We additionally implemented a color coding scheme for each directional component and FA (fractional anisotropy), and used various color tables for them to be visualized more definitely. Consequently we implemented a fancy and basic technique to visualize the directional information of fiber tracts efficiently and we confirmed the feasibility of the 24 bit color coding scheme in DTI by visualizing main fiber tracts.

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
    • /
    • 2002.11a
    • /
    • pp.133-133
    • /
    • 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.

  • PDF

Detection of Contralateral Breast Cancer Using Diffusion-Weighted Magnetic Resonance Imaging in Women with Newly Diagnosed Breast Cancer: Comparison with Combined Mammography and Whole-Breast Ultrasound

  • Su Min Ha;Jung Min Chang;Su Hyun Lee;Eun Sil Kim;Soo-Yeon Kim;Yeon Soo Kim;Nariya Cho;Woo Kyung Moon
    • Korean Journal of Radiology
    • /
    • v.22 no.6
    • /
    • pp.867-879
    • /
    • 2021
  • Objective: To compare the screening performance of diffusion-weighted (DW) MRI and combined mammography and ultrasound (US) in detecting clinically occult contralateral breast cancer in women with newly diagnosed breast cancer. Materials and Methods: Between January 2017 and July 2018, 1148 women (mean age ± standard deviation, 53.2 ± 10.8 years) with unilateral breast cancer and no clinical abnormalities in the contralateral breast underwent 3T MRI, digital mammography, and radiologist-performed whole-breast US. In this retrospective study, three radiologists independently and blindly reviewed all DW MR images (b = 1000 s/mm2 and apparent diffusion coefficient map) of the contralateral breast and assigned a Breast Imaging Reporting and Data System category. For combined mammography and US evaluation, prospectively assessed results were used. Using histopathology or 1-year follow-up as the reference standard, cancer detection rate and the patient percentage with cancers detected among all women recommended for tissue diagnosis (positive predictive value; PPV2) were compared. Results: Of the 30 cases of clinically occult contralateral cancers (13 invasive and 17 ductal carcinoma in situ [DCIS]), DW MRI detected 23 (76.7%) cases (11 invasive and 12 DCIS), whereas combined mammography and US detected 12 (40.0%, five invasive and seven DCIS) cases. All cancers detected by combined mammography and US, except two DCIS cases, were detected by DW MRI. The cancer detection rate of DW MRI (2.0%; 95% confidence interval [CI]: 1.3%, 3.0%) was higher than that of combined mammography and US (1.0%; 95% CI: 0.5%, 1.8%; p = 0.009). DW MRI showed higher PPV2 (42.1%; 95% CI: 26.3%, 59.2%) than combined mammography and US (18.5%; 95% CI: 9.9%, 30.0%; p = 0.001). Conclusion: In women with newly diagnosed breast cancer, DW MRI detected significantly more contralateral breast cancers with fewer biopsy recommendations than combined mammography and US.

Rapid Regression of White Matter Changes in Hypoglycemic Encephalopathy (저혈당성 뇌병증에서 뇌백질 변화의 빠른 퇴행)

  • Son, Sang-Wook;Lee, Kye-Ho;Yoo, Dong-Soo
    • Investigative Magnetic Resonance Imaging
    • /
    • v.18 no.4
    • /
    • pp.357-361
    • /
    • 2014
  • Purpose : In a previous report, it took several days for white matter lesions to regress in hypoglycemic encephalopathy. We present a case of rapid diffusion-weighted image (DWI) changes in hypoglycemic encephalopathy. Case Report: A 58-year-old male patient was found semi-comatous with the only abnormality in his laboratory tests showing hypoglycemia (44 mg/dL). After rapid correction of glucose level, immediate brain DWI showed bilateral subcortical white matter lesions. After about 5 hours, follow-up DWI showed resolved subcortical white matter lesions, with newly-appeared bilateral fronto-temporo-parietal cortical lesions. Conclusion: Both white matter and cortex involvement in hypoglycemic encephalopathy has been shown in several reports, but rapid regression of white matter changes in hypoglycemic encephalopathy has been rarely reported. It is important to know that MR imaging changes in hypoglycemic encephalopathy can be made as quick as just a few-hour-long.

Usefulness of the High B-value DWI in Brain Tumors (뇌종양 확산강조영상에서 High B-value의 유용성 평가)

  • Kim, Jin-tae;Byun, Jae-Hu;Park, Yong-Seong;Lee, Rae-Gon;Hwang, Seon-Kwang
    • Korean Journal of Digital Imaging in Medicine
    • /
    • v.17 no.1
    • /
    • pp.33-41
    • /
    • 2015
  • This study attempts to examine the clinical usefulness of High b-value DWI (diffusion weighted imaging) for brain tumors with an edema. Subjects were seven patients selected from 65 patients who received an MRI scan for suspected encephalopathy and confirmed diagnosis at our hospital from February to July 2015 (male: 7, average age : 66 years old). As test equipment, 3.0T MR System (ACHIEVA Release, Philips, Best, The Netherlands) and 8Channel SENSE Head Coill were used. DWI checks on the use of the variable TR 5460ms, TE 132ms, Slice Thickness 4mm, gap 1mm, Slice number 29 is, 3D T1WI is TR 8.4ms, TE 3.9ms, matrix size $240{\times}240$, Slice can set 180 piecesIt was. b value of 0, 1,000, 2,000 s/mm2 with DWI acquisition and 3D T1WI enhancement five minutes after the Slice Thickness 3mm, gap 0mm to reconstruct the upper face axis (MPR TRA CE) was. As for the experiment, in b-value 1,000 and 2,000 images, SNR and the lesion at the lesion site and CNR in the normal site opposite to the lesion are measured. WW(window width) and WL(window level) are made equal in MRICro software, and the volume of the lesion is measured from each of b-value and MPR TRA CE image. Using SPSS ver. 1.8.0.0 Mann Whitney-test was analyzed for SNR and CNR, while Kruskal-Wallis test was analyzed for volume.

  • PDF