• Title/Summary/Keyword: 확산강조 자기공명영상

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Artifacts Improvement by using the Echo Planar Imaging and Pre-Saturation Pulse Band techniques of Reduced Field-Of-View in Breast Magnetic Resonance Imaging Examination (유방 자기공명영상검사에서 감소된 영상영역의 에코평면영상기법과 사전포화기법 사용에 의한 인공물 개선)

  • Lee, Jaeheun;Kim, Hyunjin;Im, Inchul
    • Journal of the Korean Society of Radiology
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    • v.9 no.5
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    • pp.307-314
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    • 2015
  • This study was conducted in reducing the involuntary motion artifacts because of lungs and heart movements as well as the aliasing artifacts generated during the use of the reduced-FOV EPI technique while performing breast MRI. Performed on a total of 38 obesity female subjects who visited the clinic for pre-examination before surgery within the period from August 1 to November 30, 2014. The 3.0T MRI scanner equipped with a breast scanning coil. Qualitative and quantitative analyses were each used for the evaluation of the acquired images while an Paired T-test and Wilcoxon rank test were performed to check the statistical significance. The variation ratio rose by 15.69% with the additional application of a pre-saturation pulse in the lesion, by 13.72% near the lesion, and 20.63% in the fat and the contrast-to-noise ratio rose by 10.58% in and near the lesion and by 12.03% in the lesion and fat, respectively. there were increases of 22.05% and 21.42% at 0 and 1000 respectively in qulitative evaluation and growth of 16.10% in apparent diffusion coefficient. it showed a statistically significant result(p<0.05) in signal to noise ratio, contrast to noise ratio, diffusion slope coefficient and apparent diffusion coefficient. The involuntary movements artifacts that occur in the phase encoding direction and the aliasing artifacts are considered to be reduced to obtain the best image in the additional use of the pre-saturation pulse as DWI is acquired.

Pre-operative Evaluation of Consistency in Intra-axial Brain Tumor with Diffusion-weighted Images (DWI) and Conventional MR Images (확산강조영상과 고식적 자기공명영상을 이용한 수술 전 축내 뇌종양의 경도 평가)

  • Oh, Moon-Sik;Ahn, Kook-Jin;Choi, Hyun-Seok;Jung, So-Lyung;Lee, Yoon-Joo;Kim, Bum-Soo
    • Investigative Magnetic Resonance Imaging
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    • v.15 no.2
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    • pp.102-109
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    • 2011
  • Purpose : To retrospectively evaluate the usefulness of diffusion-weighted images, ADC maps and conventional MR images for determination of brain tumor consistency. Materials and Methods : Twenty-three patients with brain tumor underwent MR examinations with T1, T2 and diffusion-weighted images. Regions of interest (ROIs) were drawn in the tumors, and the measured signal intensities (SI) were normalized with the contralateral side. We evaluated the correlation between SI ratios from various images and tumor consistency assessed at surgery. In three patients with both cystic and solid components, each component was evaluated independently. Qualitatively observed SIs were also correlated with tumor consistency. Results : Statistical analysis revealed significant correlation between tumor consistency and ADC ratio (r = -0.586, p = 0.002), SI ratios on T2-weighted images (r = -0.497, p = 0.010), and observed SIs on T2-weighted images (r = -0.461, p = 0.018). The relative ratio of ADC value correlated with tumor consistency most strongly. Conclusion : The measured ratio of ADC, SI ratio and observed SI grade on T2-weighted images can provide valuable information about the consistency of brain tumor.

Fulminant Course of Acute Necrotizing Encephalopathy Followed by Serial MRI: A Case Report (급격하게 진행한 급성 괴사성 뇌병증 환자의 연속 자기공명영상 소견: 증례 보고)

  • Ji Young Lee;Kyung Mi Lee;Eung Koo Yeon;Eun Hye Lee;Eui Jong Kim
    • Journal of the Korean Society of Radiology
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    • v.82 no.5
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    • pp.1274-1280
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    • 2021
  • Acute necrotizing encephalopathy (ANE) is a rare but distinctive type of influenza-associated encephalopathy characterized by symmetric multiple lesions with an invariable thalamic involvement. Although the exact pathogenesis of ANE remains unclear, the most prevalent hypothesis is the "cytokine storm," which results in blood-brain-barrier breakdown. We present the case of a 10-year-old boy with fulminant ANE confirmed with serial MRI studies, including diffusion-weighted imaging and susceptibility-weighted imaging. A comparison of these serial images demonstrated detailed and longitudinal changes in MRI findings during the clinical course corresponding to pathophysiological changes. Our case clarifies the pathogenesis of ANE brain lesions using serial imaging studies and suggests that early immunomodulatory therapy reduces brain damage.

Using a 7.0T animal MRI comparison of ADC values and Pathologic Findings (7.0T 동물용 MRI을 이용한 종양의 현성확산계수와 병리학적 소견의 평가)

  • Seong, jae gu;Lim, cheong hwan
    • Proceedings of the Korea Contents Association Conference
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    • 2011.05a
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    • pp.201-202
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    • 2011
  • 본 연구에는 7.0T 동물용 자기공명영상장치를 이용하여 인간의 췌장암 세포인 CFPAC-1를 이종 이식한 쥐에서 자기공명영상을 획득하여 최적화된 검사 Protocol을 정립하며, 동물 실험에서 밝혀진 종양특성과 확산강조영상과의 비교 분석을 해보고 현성확산계수 영상이 췌장암 이종이식 모형의 종양 세포 내부 구조에 관하여 어떠한 정보를 제공 할 수 있는지 알아보고자 한다. 13마리의 쥐의 26개의 종양을 전형적으로 주입 후에 2~4주 뒤에 직경이 5~10mm가 되었을 때 imaged 하였으며, pathologic specimenm을 위해 sacrificed 하였다. isofluoran gas anesthesia를 이용하여 동물 마취 하였다. 사용된 장비로는 small-animal MR images (7.0-T)를 (Bruker BioSpin GmbH, Rheinstetten, Germany)이용하여 Fast T2-weighted 와 single-shot EPI DW image를 얻었다. 종양은 H&E 염색과 CD31와 VEGF에 대한 면역조직학 염색을 하여 종양의 cellularity와 microvessel density(MVD), 종양 내 괴사 정도를 평가하였다. CFPAC-1의 현성확산계수값은 $0.7327{\pm}0.1075{\pm}10^{-3}mm2/s$이였으며, 현성확산계수는 종양내 괴사 정도와 연관성을 보였다(R = 0.7417, p = 0.0001) 이처럼 현성확산계수는 종양 내 괴사 정도 등의 현미경적구조변화를 반영하는 대리인자로 사용될 수 있음을 확인하였다.

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Software Development for the Integrated Visualization of Brain Tumor and its Surrounding Fiber Tracts (뇌종양 및 그 주변 신경다발의 통합적 가시화를 위한 소프트웨어의 개발)

  • Oh Jungsu;Cho Ik Hwan;Na Dong Gyu;Chang Kee Hyun;Park Kwang Suk;Song In Chan
    • Investigative Magnetic Resonance Imaging
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    • v.9 no.1
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    • pp.2-8
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    • 2005
  • Purpose : The purpose of this study was to implement a software to visualize tumor and its surrounding fiber tracts simultaneously using diffusion tensor imaging and examine the feasibility of our software for investigating the influence of tumor on its surrounding fiber connectivity. Material and Methods : MR examination including T1-weigted and diffusion tensor images of a patient with brain tumor was performed on a 3.0 T MRI unit. We used the skull-striped brain and segmented tumor images for volume/surface rendering and anatomical information from contrast-enhanced T1-weighted images. Diffusion tensor images for the white matter fiber-tractography were acquired using a SE-EPI with a diffusion scheme of 25 directions. Fiber-tractography was performed using the streamline and tensorline methods. To correct a spatial mismatch between T1-weighted and diffusion tensor images, they were coregistered using a SPM. Our software was implemented under window-based PC system. Results : We successfully implemented the integrated visualization of the fiber tracts with tube-like surfaces, cortical surface and the tumor with volume/surface renderings in a patient with brain tumor. Conclusion : Our result showed the feasibility of the integrated visualization of brain tumor and its surrounding fiber tracts. In addition, our implementation for integrated visualization can be utilized to navigate the brain for the quantitative analysis of fractional anisotropy to assess changes in the white matter tract integrity of edematic and peri-edematic regions in a number of tumor patients.

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Diffusion-Weighted Imaging as a Stand-Alone Breast Imaging Modality (독립적 검사 방법으로서의 확산강조 자기공명영상검사)

  • Hee Jung Shin;Su Hyun Lee;Woo Kyung Moon
    • Journal of the Korean Society of Radiology
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    • v.82 no.1
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    • pp.29-48
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    • 2021
  • Diffusion-weighted magnetic resonance imaging (DW MRI) is a fast unenhanced technique that shows promise as a stand-alone modality for cancer screening and characterization. Currently, DW MRI may have lower sensitivity than that of dynamic contrast-enhanced MRI as a standalone modality for breast cancer detection but superior to that of mammography, which may provide a useful alternative for supplemental screening. Standardized acquisition and interpretation of DW MRI can improve the image quality and reduce the variability of the results. Furthermore, high-resolution DW MRI, with advanced techniques and postprocessing, will facilitate better detection and characterization of subcentimeter cancers and reduce false-negatives and false-positives. Future results from ongoing prospective multicenter clinical trials using standardized and optimized protocols will facilitate the use of DW MRI as a stand-alone modality.

Transient Splenial Lesions in the Splenium of Corpus Callosum in Seven Patients: MR Findings and Clinical Correlations (뇌량 팽대의 일과성 병변: 7명의 환자에서의 자기공명 영상소견과 임상 양상의 연관성)

  • Park, Ju Young;Lee, In Ho;Song, Chang June;Hwang, Hee Youn
    • Investigative Magnetic Resonance Imaging
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    • v.17 no.1
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    • pp.1-7
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    • 2013
  • Purpose : The purpose of this study is to correlate the imaging findings and the clinical findings in patients with transient splenial lesions (TSL). Materials and Methods: Total of 7 patients (M: F = 4: 3; age range 11 - 38 years, mean age 25.5 years) were studied between November 2006 and April 2011. The MRI findings and clinical findings in all patients were retrospectively reviewed. The location, MR signal intensity, restricted diffusion, enhancement pattern and reversibility from the follow up images were reviewed. Clinical features were reviewed with respect to the presented symptoms, signs, treatment and outcome. Results: The lesions were located in the splenium of corpus callosum in all patients. All lesions showed high signal intensity on diffusion weighted imaging (DWI), and six patients showed restricted diffusion on the apparent diffusion coefficient (ADC) map. ADC map was not available in one patient. All lesions (n = 7) showed high signal intensity on the T2 weighted image (T2WI). Five of the patients (71.4%) with follow up images (range 7 - 34 days) showed complete resolution of focal high signal intensity on DWI, with recovery of ADC values as well as T2WI. After contrast media administration, none of the lesions showed any enhancements. All lesions with various etiologies including TB medication were developed in younger age patients and showed reversibility after the acceptable period of minimum 7 days with conservative treatment. Conclusion: All TSL showed nonspecific imaging findings, including restricted diffusion on DWI and ADC map on the initial images. However, reversibility of the lesions and the young age preference can be a characteristic finding of TSL with acceptable period of minimum 7 days. In addition, to keep it in mind that various etiologies including TB medication may cause TSL, is important for radiologists as well as clinicians.

Diffusion-Weighted MR Neurography with Unidirectional Motion-Probing Gradient to Evaluate Lumbar Nerve Roots at 1.5T MR (요추 신경근 평가를 위한 1.5T MR의 단일 방향 경사자장을 사용한 확산강조 자기공명신경조영)

  • Na Yeon Yoon;Doo Hoe Ha;Sang Min Lee;Hye Jung Choi
    • Journal of the Korean Society of Radiology
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    • v.85 no.3
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    • pp.607-617
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    • 2024
  • Purpose Recent studies have demonstrated the usefulness of diffusion-weighted MR neurography (DW MRN) for assessing nerve roots. This study aimed to evaluate the utility of DW MRN with a unidirectional motion-probing gradient (MPG) for the lumbar nerve roots at 1.5T MR. Materials and Methods Sixty-four lumbar spine MRI scans with DW MRN using anteroposterior unidirectional MPG were retrospectively analyzed. Any changes in the 512 lumbar spinal nerve roots from L3 to S1 were evaluated using T2-weighted imaging (T2WI), contrast-enhanced T1-weighted imaging (CE T1WI), and DW MRN, with agreement and correlation analysis. Results T2WI revealed compression of 78 nerve roots, and CE T1WI revealed 52 instances of nerve root enhancement. Sixty-seven nerve roots showed swelling and hyperintensity on DW MRN. A total of 42 nerve roots showed changes in the CE T1WI and DW MRN sequences. Moderate to substantial agreement and moderate positive correlation were observed between DW MRN and CE T1WI, as well as DW MRN and T2WI (κ = 0.59-0.65, ρ = 0.600-0.653). Conclusion DW MRN with unidirectional anteroposterior MPG can help evaluate neuritisrelated changes in spinal nerve roots and could serve as a sequence capable of complementing or substituting gadolinium CE imaging.

The Study on Signal to Noise Ratio of Single-Shot Turbo Spin Echo to Reduce Image Distortion in Brain Stem Diffusion MRI (뇌줄기 확산강조 자기공명영상검사 시 뒤틀림을 줄이기 위한 SS-TSE 기법의 신호대잡음비 연구)

  • Koo, Nohyun;Lee, Hobeom;Choi, Kwanwoo;Son, Soonyong;Yoo, Beonggyu
    • Journal of the Korean Society of Radiology
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    • v.10 no.4
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    • pp.241-246
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    • 2016
  • The purpose of this study was to investigate the problems of low signal-to-noise ratio(SNR) of single-shot turbo spin echo(SS-TSE) by quantifying numerically decreased signal to noise ratio. Thirty five patients without brain disease underwent diffusion MRI in 3T scanner from July to October in 2015. Single shot echo planar imaging(SS-EPI) which is conventionally used in MRI was taken to compared SS-TSE in SNR of medulla oblongata. As a result, SNR of SS-TSE diffusion(b0=$314.41{\pm}42.96$, b1000=$117.33{\pm}14.04$) is than SS-EPI diffusion(b0=$514.84{\pm}48.97$, b=$208.65{\pm}25.70$) lower in b=0 image(38.9%) and b=1,000 image(43.8%). Thus, diffusion MR using SS-EPI of MS-EPI should be taken for diagnosis of disease in brain stem due to decreased SNR of diffusion using SS-TSE.

Pathophysiology-based Interpretation of Magnetic Resonance Imaging and Management of Cerebral Fat Embolism: Case Report and Review of Literature (병리 생리학적 근거를 바탕으로한, 뇌 지방색전증의 자기공명영상의 해석 및 치료: 증례 보고 및 문헌고찰)

  • Park, Jae-Hyo;Lim, Byung-Chul
    • Investigative Magnetic Resonance Imaging
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    • v.14 no.1
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    • pp.69-73
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    • 2010
  • Cerebral fat embolism (CFE) is a rare, albeit potentially lethal complication of long-bone fractures. All trauma patients who are initially lucid and subsequently experience mental status deterioration should undergo immediate evaluation of possible CFE. In the present case, magnetic resonance imaging (MRI) was the most sensitive technique for the diagnosis of CFE, particularly the use of diffusionweighted images (DWI). The authors present this case to report a pathophysiologybased interpretation of the MR characteristics and treatment of CFE.