• Title, Summary, Keyword: MRI

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Effective of Body Temperature Increasing during Brain MRI scan (MRI 검사 시 체온상승 효과: 1.5 T vs 3.0 T)

  • Kim, Myeong Seong;Lee, Jongwoong;Jung, Jaeeun
    • Journal of the Korean Society of Radiology
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    • v.11 no.1
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    • pp.49-54
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    • 2017
  • As the Radiofrequency(RF) increases with the magnetic field strength, the wavelength of the RF excitation field becomes smaller, which leads to more the thermal effect in the human-body placed in the electric field. MRI scanner used was GE signa 1.5T, HDx 3.0T and Philips 3.0T with same routine clinical sequence protocol. Therefore temperature was measured before and after each scan. Taken the temperatures in the ear with ear infra-red type thermometer(Braun co). 3.0T were temperature increases more than $0.15^{\circ}C$ and GE 3.0T MRI equipment about $0.14^{\circ}C$ higher than the Philips 3.0T MRI(p<0.012). Psychogenic status was investigated by the survey respondents about their status can not just answer therefore, a little different from the expected. In our study of Thermal effect of clinical MRI with clinical protocol sequence, we found that the 3.0T in the body-temperature rise was greater than the 1.5T. Therefore, in clinical 3.0T examine the dangerous situation caused by the temperature rise occurred (burns, impaired thermoregulatory mechanism in patients with high-temperature damage, exhaustion occurs due to excessive sweating), not to appear the more watched the patient's condition with procedure.

Image Evaluation Via $SUV_{LBM}$ for Normal Regions of VOI by Using Whole Body Images Obtained from PET/MRI and PET/CT (F-18 FDG PET/MRI와 PET/CT 전신 영상에서 VOI를 이용한 정상부위의 $SUV_{LBM}$-최대치에 의한 영상평가)

  • Park, Jeong-Kyu;Kim, Sung-Kyu;Cho, Ihn-Ho;Kong, Eun-Jung;Park, Meyong-Hwan
    • Progress in Medical Physics
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    • v.24 no.1
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    • pp.68-75
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    • 2013
  • The purpose of this research is to compare and analyze $SUV_{LBM}$-maximum of normal regions using VOI (the volume of interest) in order to enhance the diagnostic level in whole body images of PET/CT and PET/MRI for 26 health check-up participants. In particular, we try to set up $SUV_{LBM}$-maximum data that can be used in synchronous evaluation for PET/CT and PET/MRI without contrast media. The evaluation of $SUV_{LBM}$-maximum for normal regions of whole body PET/CT and whole body PET/MRI shows that the image of PET/MRI differs very significantly from the reference image of PET/CT (p<0.0001). However, they exhibit high correlations in view of statistics (R>0.8). From this research, we suggest that the decision in the evaluation of $SUV_{LBM}$-maximum for PET/MRI should be made with the reduction of about 26.3%, while one should decide with the reduction of about 29.3% when the contrast media is used. It is helpful to interpret all image of PET/CT and PET/MRI using $SUV_{LBM}$-maximum for convenience and efficiency.

MRI Diagnosis of the Tear Pattern of Menisci (반월상 연골판 파열 양상의 자기공명영상 진단)

  • Ahn, Jin Hwan;Ha, Chul Won;Ahn, Joong Mo;Kim, Sang Hyun
    • Journal of the Korean Arthroscopy Society
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    • v.2 no.2
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    • pp.151-154
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    • 1998
  • In the diagnosis of the meniscal tear of the knee, the high accuracy of the MRI diagnosis is well-known, but the accuracy of the MRI in the diagnosis of the very pattern of the tear of menisci is not well-established. The purpose of this study is to give some informations to consider in the diagnosis and therapeutic planning of torn menisci. The authors performed a retrospective study comparing the MRI and arthroscopic findings of 141 knees which had undergone arthroscopic surgery from Mar. 1997 to Mar. 1998. The results are as follows. In the diagnosis of tear of the menisci, MRI had sensitivity of 91%, specificity of 96%, accuracy of 95%. The mismatch of the tear patterns of the menisci between MRI and arthroscopic findings was identified in 59%, especially high in flap tear(100%), complex tear(84%), peripheral tear(55%). In conclusion, MRI is very accurate in the diagnosis of the tear of menisci, but the tear patterns of the menisci cannot be accurately determined by MRI. In the cases of flap tears, complex tears and peripheral tears, it is more difficult to determine the tear patterns of the menisci by MRI. False-negative rate of MRI was especially high(44%) in the peripheral tear type. So, other clinical correlations should be made in determination of the presence of the tear in the diagnosis of peripheral tear of the menisci.

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Comparison between cone beam computed tomography and magnetic resonance imaging of the temporomandibular joint (측두하악관절에 대한 cone beam형 전산화단층영상과 자기공명영상의 비교)

  • Kim, Gyu-Tae;Choi, Yong-Suk;Hwang, Eui-Hwan
    • Imaging Science in Dentistry
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    • v.38 no.3
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    • pp.153-161
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    • 2008
  • Purpose : To compare and evaluate the diagnostic ability of cone beam computed tomography (CBCT) and magnetic resonance imaging (MRI) of the temporomandibular joint (TMJ). Materials and Methods : CBCT and MRI of 46 TMJs of 23 patients with TMJ disorders were evaluated. They were divided into 3 groups according to the position of the articular disc of the TMJ at closed mouth position and the reduction of the disc during open mouth position on MRI: no disc displacement group (NDD), disc displacement with reduction group (DDR), and disc displacement without reduction group (DDWR). With PACS viewing soft-wares, position of mandibular condyle in the articular fossa, osseous change of mandibular condyle, shape of articular fossa, and mediolateral and anteroposterior dimensions of mandibular condyle were evaluated on CBCT and MRI. Each value was tested statistically. Results : The position of mandibular condyle in the articular fossa were concentric in the NDD, DDR, and DDWR of CBCT and NDD of MRI. However, condyle was positioned posteriorly in DDR and DDWR of MRI. Flattening, sclerosis and osteophyte of the mandibular condyle were much more apparent on DDR of CBCT than MRI. And the erosion of the condyle was much more apparent on DDWR of MRI than CBCT. Box and Sigmoid types of articular fossa were found most frequently in DDR of MRI. Flattened type was found most frequently in DDR of CBCT and deformed type was found most frequently in DDWR of CBCT. No significant difference in mediolateral and anteroposterior dimensions were shown on CBCT and MRI. Conclusion : Since MRI and CBCT has unique diagnostic imaging ability, both modalities should be used together to supplement each other to evaluate TMJ.

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Brain Activation Evoked by Sensory Stimulation in Patients with Spinal Cord Injury : Functional Magnetic Resonance Imaging Correlations with Clinical Features

  • Lee, Jun Ki;Oh, Chang Hyun;Kim, Ji Yong;Park, Hyung-Chun;Yoon, Seung Hwan
    • Journal of Korean Neurosurgical Society
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    • v.58 no.3
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    • pp.242-247
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    • 2015
  • Objective : The purpose of this study is to determine whether the changes of contralateral sensorimotor cortical activation on functional magnetic resonance imaging (fMRI) can predict the neurological outcome among spinal cord injury (SCI) patients when the great toes are stimulated without notice. Methods : This study enrolled a total of 49 patients with SCI and investigated each patient's preoperative fMRI, postoperative fMRI, American Spinal Injury Association (ASIA) score, and neuropathic pain occurrence. Patients were classified into 3 groups according to the change of blood oxygenation level dependent (BOLD) response on perioperative fMRI during proprioceptive stimulation with repetitive passive toe movements : 1) patients with a response of contralateral sensorimotor cortical activation in fMRI were categorized; 2) patients with a response in other regions; and 3) patients with no response. Correlation between the result of fMRI and each parameter was analyzed. Results : In fMRI data, ASIA score was likely to show greater improvement in patients in group A compared to those belonging to group B or C (p<0.001). No statistical significance was observed between the result of fMRI and neuropathic pain (p=0.709). However, increase in neuropathic pain in response to the signal change of the ipsilateral frontal lobe on fMRI was statistically significant (p=0.030). Conclusion : When there was change of BOLD response at the contralateral sensorimotor cortex on perioperative fMRI after surgery, relief of neurological symptoms was highly likely for traumatic SCI patients. In addition, development of neuropathic pain was likely to occur when there was change of BOLD response at ipsilateral frontal lobe.

Brain-wave Analysis using fMRI, TRS and EEG for Human Emotion Recognition (fMRI와 TRS와 EEG를 이용한 뇌파분석을 통한 사람의 감정인식)

  • Kim, Ho-Duck;Sim, Kwee-Bo
    • Journal of the Korean Institute of Intelligent Systems
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    • v.17 no.6
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    • pp.832-837
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    • 2007
  • Many researchers are studying brain activity to using functional Magnetic Resonance Imaging (fMRI), Time Resolved Spectroscopy(TRS), Electroencephalography(EEG), and etc. They are used detection of seizures or epilepsy and deception detection in the main. In this paper, we focus on emotion recognition by recording brain waves. We specially use fMRI, TRS, and EEG for measuring brain activity Researchers are experimenting brain waves to get only a measuring apparatus or to use both fMRI and EEG. This paper is measured that we take images of fMRI and TRS about brain activity as human emotions and then we take data of EEG signals. Especially, we focus on EEG signals analysis. We analyze not only original features in brain waves but also transferred features to classify into five sections as frequency. And we eliminate low frequency from 0.2 to 4Hz for EEG artifacts elimination.

Development of Tissue Equivalent Materials for a Multi-modality (CT&MRI) Phantom in MRI-guided Radiation Treatment

  • Seol, Yunji;Kim, Jina;Kim, Aeran;Hwang, Jinho;Oh, Taegeon;Shin, Jin-sol;Jang, Hong Seok;Choi, Byung Ock;Kang, Young-nam
    • Journal of the Korean Physical Society
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    • v.73 no.7
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    • pp.1012-1018
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    • 2018
  • This study proposed to develop a phantom material that can represent the various contrasts of both MRI and CT images and is available to use in MRI-guided radiation treatment. Materials used for making a phantom that can be used for both MRI and CT image were agarose (T2 modifier), gadolinium-based contrast agent (T1 modifier), sodium fluoride (CT number modifier), and distilled water. They were mixed at various composition ratios and stirred until transparent. For the relationship between the ingredients and values, 48 samples were manufactured at various composition ratios. The relationship was expressed as equations, to be able to get the composition ratios of organs that we wanted to make. MR relaxation times were measured using 1.5 T MRI equipment. CT scans were performed at 120 kVp and extracted CT numbers from images. Based on the fitted equations derived from the relationship between ingredients and values, materials were manufactured using the composition ratio of human organs; brain (white and gray matter), liver, spleen, kidney, and prostate. The all values were within the reference range, but some exceeded the range due to the image noise. A phantom composed of substitutes made from the derived equations added other substances of different density like bone or lung can be used as an inhomogeneity dose calculation phantom for both CT and MRI. Furthermore, it can be applied to MRI-only based RTP systems and MRI-guided radiation treatment QA in the future.

Cortical Dysplasia: Tc-99m ECD SPECT Findings and Comparative Study with MRI according to Pathologic Grading (뇌피질 이형성증: Tc-99m ECD SPECT 소견과 병리적 등급에 따른 MRI와 비교 연구)

  • Park, Soon-Ah;Lim, Seok-Tae;Sohn, Myung-Hee;Chung, Gyung-Ho
    • The Korean Journal of Nuclear Medicine
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    • v.35 no.1
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    • pp.23-32
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    • 2001
  • Purpose: Cortical dysplasia (CD) designates a diverse group of malformations resulting from one or more abnormalities in the development of the cerebral cortex. We investigated the findings of interictal SPECT and the diagnostic usefulness of interical and ictal SFECT according to pathological grading (PG) in comparison with MRI. Materials and Methods: This study included 16 patients (M:F=9:7, age: $19.9{\pm}11.8$ yrs) with pathologically proven CD. Tc-99m ECD SPECT was performed in all patients: interictal 11, interictal and ictal 3, ictal 2. MRI were obtained in all patients and image analysis was done blindly as to the result of SPECT. Pathologic findings of CD were classified into grade 1 G1, dyslamination), grade 2 (G2, dysplastic neurons) and grade 3 (G3, balloon cells). We compared SFECT with MRI in lesions-to-lesions and analyzed the result according to PG. Results: In SFECT and MRI. 38 and 27 lesions were visually recognized. In 14 interictal SPECT, variable findings in 35 lesions were demonstrated: 25 were hypoperfusion, 7 hyperperfusion, 2 heterotopic perfusion in the white matter. By comparison between two studios, missed lesions were founded: SPECT were 1 lesion, MRI 12. Review of missed 12 lesions of MRI were followed according to PG: G1 patients were 16.7% (4/19), G2 40.0% (6/15), and G3 50% (2/4). Conclusion: Interictal SFECT in CD showed variable findings such as hypoperfusion, hyperperfusion or heterotopic perfusion. However, for detection of missed CD on MRI, SFECT may help to detect a functional abnormality of the lesion with high PG.

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A Study on Utility of Magnetic Resonance Imaging for Female Pelvic Cavity using Enteral MRI Contrast Media (Enteral MRI contrast media를 이용한 여성골반 자기공명영상의 유용성)

  • Kim, Ham-Gyum
    • Journal of radiological science and technology
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    • v.20 no.1
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    • pp.29-34
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    • 1997
  • For radiological test in soft tissue or neighboring part with same signal intensity, proper test method and equipment shall be selected as needed. In case of female pelvic cavity, ultrasonography or computed tomography alternatively used, but MRI can be more usefully applied to design treatment method or operation plan by improving the diagnostic accuracy and careful observation of lesion characteristics. Magnetic Resonance Imaging using recently developed Enteral MRI contrast media can acquire more diagnostic information than using only intravenous contrast media. Thus this study attempted to examine the utility of anatomic structure and diagnostic acquisition by imaging the female pelvic cavity using Enteral MRI contrast media. As a result of analyzing magnetic resonance Imaging after administering Enteral MRI contrast media to pelvic cavity suspect patients, more diagnostic information media could be acquired than only using Intravenous contrast. Expecially, in the diagnosis of lesion position, shape, distinction from neighboring tissues it is thought that external Enteral MRI contrast media should be used.

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Brain-wave Analysis using fMRI, TRS and EEG for Human Emotion Recognition (fMRI와 TRS와 EEG 를 이용한 뇌파분석을 통한 사람의 감정 인식)

  • Kim, Ho-Duck;Sim, Kwee-Bo
    • Proceedings of the Korean Institute of Intelligent Systems Conference
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    • pp.7-10
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    • 2007
  • 많은 과학자들은 인간의 사고를 functional Magnetic Resonance Imaging (fMRI), Time Resolved Spectroscopy(TRS), Electroencephalography(EEG)등을 이용해서 두뇌 활동 영역을 연구하고 있다. 주로 의학 분야와 심리학의 영역에서 두뇌의 활동을 연구하여 간질이나 발작을 알아내고 거짓말 탐지 분야에서도 사용된다. 본 논문에서는 사람의 두뇌활동을 측정하여 인간의 감정을 인식하는 연구에 중점을 두었다. 특히 fMRI와 TRS 그리고 EEG를 이용해서 사람의 두뇌활동을 측정하는 연구를 하였다. 많은 연구자들이 한 가지 측정 장치만을 사용하여서 측정하거나 fMRI와 EEG를 동시에 측정하는 연구를 진행하고 있다. 현재에는 단순히 두뇌의 활동을 측정하거나 측정시 발생하는 잡음들을 제거하는 연구들에 중점을 두고 진행되고 있다. 본 연구에서는 fMRI와 TRS를 동시에 측정하여 얻은 두뇌 활동 데이터를 가지고 감정에 따른 활동영역의 EEG신호를 측정하였다. EEG 신호분석에 있어서 기존의 뇌파만을 가지고 특정을 찾아내는 것을 넘어서 각각의 채널에서 기록되는 뇌파의 파형을 주파수에 따라서 분류하고 정확한 측정을 위해 낮은 주파수를 제거하고 연구자가 필요한 부분의 뇌파를 분석하였다.

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