• Title, Summary, Keyword: MRI

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High-resolution MR Imaging of Carotid Atherosclerotic Plaques (경동맥 경화판의 고해상도 자기공명영상)

  • Shin, Won-Seon;Kim, Sung-Mok;Choe, Yeon-Hyeon
    • Investigative Magnetic Resonance Imaging
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    • v.16 no.2
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    • pp.97-102
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    • 2012
  • High-resolution carotid MRI allows visualization of carotid atherosclerotic plaque characteristics. MRI serves as a noninvasive option for the detection of active plaque inflammation and intraplaque hemorrhage. Significant gains in signal-tonoise ratio and contrast-to-noise ratio can be obtained for carotid atheroma imaging at 3T compared with 1.5T. Normalized wall index or wall area on MRI has shown its efficacy in monitoring the response after medical therapy. $T(2)^*$ quantification in carotid plaques before and after the administration of ultrasmall superparamagnetic iron oxide particles shows difference in response to treatment according to drug doses. In conclusion, high-resolution MRI is useful in the diagnosis and monitoring of carotid atherosclerotic plaques prone to transient ischemic attack and stroke.

Breast Cancer Screening with MRI (유방암 스크리닝 자기공명영상)

  • Cho, Nariya;Moon, Woo-Kyung
    • Investigative Magnetic Resonance Imaging
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    • v.16 no.1
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    • pp.1-5
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    • 2012
  • Breast MRI is the most accurate adjunctive to the mammography for the screening of breast cancer. Despite lack of randomized controlled trials on the effectiveness of MRI screening, it is now recommended for the women at high risk for breast cancer by the American Cancer Society and the National Comprehensive Cancer Network based on several prospective observational studies. In Korea, a retrospective study reported that preoperative MRI screening of the contralateral breast in women with unilateral breast cancer was associated with reduced metachronous cancer incidence. To introduce breast MRI as a supplemental modality to screening mammography in Korea, standardization and education of interpretation, establishment of MR-guided biopsy and adequate indication, and evaluation of cost-effectiveness and should be preceded.

Experience with 7.0 T MRI in Patients with Supratentorial Meningiomas

  • Song, Sang Woo;Son, Young Don;Cho, Zang-Hee;Paek, Sun Ha
    • Journal of Korean Neurosurgical Society
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    • v.59 no.4
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    • pp.405-409
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    • 2016
  • Meningiomas are typically diagnosed by their characteristic appearance on conventional magnetic resonance imaging (MRI). However, detailed image findings regarding peri- and intra-tumoral anatomical structures, tumor consistency and vascularity are very important in pre-surgical planning and surgical outcomes. At the 7.0 T MRI achieving ultra-high resolution, it could be possible to obtain more useful information in surgical strategy. Four patients who were radiologically diagnosed with intracranial meningioma in 1.5 T MRI underwent a 7.0 T MRI. Three of them underwent surgery afterwards, and one received gamma knife radiosurgery. In our study, the advantages of 7.0 T MRI over 1.5 T MRI were a more detailed depiction of the peri- and intra-tumoral vasculature and a clear delineation of tumor-brain interface. In the safety issues, all patients received 7.0 T MRI without any adverse event. One disadvantage of 7.0 T MRI was the reduced image quality of skull base lesions. 7.0 T MRI in patients with meningiomas could provide useful information in surgical strategy, such as the peri-tumoral vasculature and the tumor-brain interface.

Retinotopy of human visual cortex; A Study with 3T fMRI

  • 윤효운;정관진;임동미;조은미;송명성;연은경;박현욱
    • Proceedings of the KSMRM Conference
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    • pp.109-109
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    • 2002
  • Purpose: The aim of the study is to see the representation patterns of human visual cortex by perceiving some geometrical shapes. Method: 3 humans as subjects for the fMRI experiment. A classical block or box car design was used as experimental paradigm. 3 different types of fan shapes and concentric circles were presented.

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A Study on the Socio-economic Characteristics of Magnetic Resonance Image(MRI) Uses in Korea (우리나라 MRI 이용의 사회경제적 특성)

  • 김루시아;문옥륜
    • Health Policy and Management
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    • v.2 no.2
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    • pp.194-220
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    • 1992
  • In recent years there has been a rapid influx of high cost MRI equipment into Korea. This diffusion has raised concerns about the changes it will bring for the health care utilization. Therefore, the purpose of this study is to identify socio-economic characteristics of MRI uses in Korea. A structured questionnaire was designed for this purpose, and 1, 091 users were surveyed at the 35 MRI units of 33 hospitals during a week, sometimes March 1992. The study reveals that high cost technology such as MRI, CT scanner is so prevalent in Korea. This is particularly the case in metropolitan areas. Among others, Seoul has the highest percentage of MRI equipment, 51.05%, Pusan 12.10% and Kwangju 11.9%. Unfortunately, most high cost technology equipments are foreign products. Thus, hospitals with such a high cost technology have difficulties in maintenance of the equipment. The average performance of MRI equipment has declined from 10.2 cases per day in 1988 to 7.16 cases in March 1992. Due to the rapid increase, the performance of MRI equipment seems to be deterioration. Male usere are dominant in the case of MRI use. The utilization rate has positively increased with the rise of educational level of users. The same is true for the level of income; the MRI utilization rate by income level shows that it is negatively proportional to income, which indicates that the poor have difficulties in the use of high cost technology. Particularly, the cost of MRI is so high that ordinary patients are unable to pay for it. For example, 86.3% of respondents have answered that the cost is too high even though they are insured by health insurance. This is the first empirical study on the use status of MRI. The information obtained in this study is sufficient to maintain that the Korean health insurance programme is urgently in need of improving the insurance benefit schemes. The easiest way to do this is to include provision of high cost technology service into the benefit package.

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The Feasibility for Whole-Night Sleep Brain Network Research Using Synchronous EEG-fMRI (수면 뇌파-기능자기공명영상 동기화 측정과 신호처리 기법을 통한 수면 단계별 뇌연결망 연구)

  • Kim, Joong Il;Park, Bumhee;Youn, Tak;Park, Hae-Jeong
    • Sleep Medicine and Psychophysiology
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    • v.25 no.2
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    • pp.82-91
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    • 2018
  • Objectives: Synchronous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has been used to explore sleep stage dependent functional brain networks. Despite a growing number of sleep studies using EEG-fMRI, few studies have conducted network analysis on whole night sleep due to difficulty in data acquisition, artifacts, and sleep management within the MRI scanner. Methods: In order to perform network analysis for whole night sleep, we proposed experimental procedures and data processing techniques for EEG-fMRI. We acquired 6-7 hours of EEG-fMRI data per participant and conducted signal processing to reduce artifacts in both EEG and fMRI. We then generated a functional brain atlas with 68 brain regions using independent component analysis of sleep fMRI data. Using this functional atlas, we constructed sleep level dependent functional brain networks. Results: When we evaluated functional connectivity distribution, sleep showed significantly reduced functional connectivity for the whole brain compared to that during wakefulness. REM sleep showed statistically different connectivity patterns compared to non-REM sleep in sleep-related subcortical brain circuits. Conclusion: This study suggests the feasibility of exploring functional brain networks using sleep EEG-fMRI for whole night sleep via appropriate experimental procedures and signal processing techniques for fMRI and EEG.

Is the Utilization of MID Services affected by the Implementation of Insurance Coverage?: Based on Claim Data of a General Hospital (MRI 보험급여 적용이 진료이용량에 미치는 영향 : 한 종합병원의 청구자료를 중심으로)

  • Kim, Seon-Hee;Kim, Chun-Bae;Cho, Kyung-Hee;Kang, Im-Ok
    • Health Policy and Management
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    • v.18 no.2
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    • pp.1-18
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    • 2008
  • As medical insurance had been implemented for Magnetic Resonance Imaging (MRI) from January 1, 2005, this study investigated whether there had been any change in the amount of the medical care utilization of patients who undertook MRI before and after the insurance coverage, and was to examine factors affecting the amount of medical care utilization of MRI. Data were collected from patients who undertook MRI before and after the insurance coverage for a year at a general hospital in Kyeanggi-do. $X^2$ and t-test were used for the analysis of their general characteristics, the number of MRI, and its medical costs before and after the insurance coverage, and hierarchical multiple regression analysis for the factors affecting the amount of the medical care utilization of MRI. The results of this study were as follows. First, the number of MRI after the insurance coverage was significantly decreased. Second, there was no significant difference in the total medical costs of MRI after the insurance coverage, but a significant difference was found in patient's share of medical costs. Third, six variables were found to be affecting the amount of the medical care utilization of MRI, and the variables showed to lead the number of MRI decrease after the insurance coverage. These six factors explained 21.4% of the total number of MRI. As MRI had been covered by insurance, the use of MRI and patient's share of the costs were deceased, but the total medical costs were not affected. Reasons for that could be found in that MRI insurance, different from the case of CT insurance coverage, was allowed not to cover some items and the kinds of diseases subjected to the insurance coverage were extremely limited, lowering insurance prescription rate. In addition to that, the average medical cost of MRI was not changed after the insurance coverage. Therefore, as future measures for the MRI insurance, coverage, it should be considered to allow insurance coverage to no coverage items and to expand the scope of benefit coverage, or to lower patient's share of the costs. Furthermore, researches should be done to explore how recipients will act and how suppliers will react if the coverage is expanded, including expanding the scope of coverage and reducing patient's share of the costs, as well as to conduct research on its economic analysis according to case mix.

Comparison of SUV for PET/MRI and PET/CT (인체 각 부위의 PET/MRI와 PET/CT의 SUV 변화)

  • Kim, Jae Il;Jeon, Jae Hwan;Kim, In Soo;Lee, Hong Jae;Kim, Jin Eui
    • The Korean Journal of Nuclear Medicine Technology
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    • v.17 no.2
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    • pp.10-14
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    • 2013
  • Purpose: Due to developed simultaneous PET/MRI, it has become possible to obtain more anatomical image information better than conventional PET/CT. By the way, in the PET/CT, the linear absorption coefficient is measured by X-ray directly. However in case of PET/MRI, the value is not measured from MRI images directly, but is calculated by dividing as 4 segmentation ${\mu}-map$. Therefore, in this paper, we will evaluate the SUV's difference of attenuation correction PET images from PET/MRI and PET/CT. Materials and Methods: Biograph mCT40 (Siemens, Germany), Biograph mMR were used as a PET/CT, PET/MRI scanner. For a phantom study, we used a solid type $^{68}Ge$ source, and a liquid type $^{18}F$ uniformity phantom. By using VIBE-DIXON sequence of PET/MRI, human anatomical structure was divided into air-lung-fat-soft tissue for attenuation correction coefficient. In case of PET/CT, the hounsfield unit of CT was used. By setting the ROI at five places of each PET phantom images that is corrected attenuation, the maximum SUV was measured, evaluated %diff about PET/CT vs. PET/MRI. In clinical study, the 18 patients who underwent simultaneous PET/CT and PET/MRI was selected and set the ROI at background, lung, liver, brain, muscle, fat, bone from the each attenuation correction PET images, and then evaluated, compared by measuring the maximum SUV. Results: For solid $^{68}Ge$ source, SUV from PET/MRI is measured lower 88.55% compared to PET/CT. In case of liquid $^{18}F$ uniform phantom, SUV of PET/MRI as compared to PET/CT is measured low 70.17%. If the clinical study, the background SUV of PET/MRI is same with PET/CT's and the one of lung was higher 2.51%. However, it is measured lower about 32.50, 40.35, 23.92, 13.92, 5.00% at liver, brain, muscle, fat, femoral head. Conclusion: In the case of a CT image, because there is a linear relationship between 511 keV ${\gamma}-ray$ and linear absorption coefficient of X-ray, it is possible to correct directly the attenuation of 511 keV ${\gamma}-ray$ by creating a ${\mu}$map from the CT image. However, in the case of the MRI, because the MRI signal has no relationship at all with linear absorption coefficient of ${\gamma}-ray$, the anatomical structure of the human body is divided into four segmentations to correct the attenuation of ${\gamma}-rays$. Even a number of protons in a bone is too low to make MRI signal and to localize segmentation of ${\mu}-map$. Therefore, to develope a proper sequence for measuring more accurate attenuation coefficient is indeed necessary in the future PET/MRI.

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Comparison of Multiparametric and Biparametric MRI in First Round Cognitive Targeted Prostate Biopsy in Patients with PSA Levels under 10 ng/mL

  • Lee, Dong Hoon;Nam, Jong Kil;Lee, Seung Soo;Han, Ji-Yeon;Lee, Joon Woo;Chung, Moon Kee;Park, Sung Woo
    • Yonsei Medical Journal
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    • v.58 no.5
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    • pp.994-999
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    • 2017
  • Purpose: To determine the efficacy of cognitive targeted prostate biopsy using biparametric magnetic resonance imaging (b-MRI) for patients with prostate-specific antigen levels under 10 ng/mL. Materials and Methods: We reviewed data from 123 consecutive patients who underwent cognitive targeted prostate biopsy using prostate MRI. Of these patients, the first 55 underwent prostate biopsy using multiparametric MRI (mp-MRI), and the remaining 68 underwent prostate biopsy using b-MRI. For b-MRI, we generated T2 weighted axial imaging and diffusion-weighted imaging sequences. We found that 62 of the 123 men had suspicious lesions on MRI (32 of the 55 men in the mp-MRI group and 30 of the 68 men in the b-MRI group). We compared the prostate cancer detection rates and the proportions of clinically significant prostate cancer between the different MRI sequences. Results: Between the two MRI groups, there were no statistically significant differences in prostate cancer detection rate and proportions of clinically significant prostate cancer (41.8% vs. 30.9%, p=0.208 and 82.6% vs. 76.2%, p=0.598). Among the 62 men who had suspicious lesions on MRI, the prostate cancer detection rates were 62.5% and 63.3% (p=0.709) in the mp-MRI and b-MRI groups, respectively, and the proportions of clinically significant prostate cancer were 95.0% and 84.2% (p=0.267). Conclusion: Prostate biopsy using b-MRI showed similar performance to that using mp-MRI for detecting prostate cancer and clinically significant prostate cancer. Considering the satisfactory performance and cost effectiveness of b-MRI, this technique could be a good option for obtaining intraprostatic information for first round prostate biopsy.

Retrospective Review of Magnetic Resonance Imaging of the Lumbosacral Spine: Are We Overinvestigating?

  • Khanduja, Suchit;Loomba, Vivek;Salama-Hannah, Joseph;Upadhyay, Aman;Khanduja, Neha;Chauhan, Gaurav
    • Neurospine
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    • v.15 no.4
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    • pp.383-387
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    • 2018
  • Objective: Lower back pain (LBP) is a worldwide health problem, and magnetic resonance imaging (MRI) is a common modality used to aid in its diagnosis. Although specific guidelines for assessing the necessity of MRI usage exist, the use of MRI as the initial imaging method for LBP seems to be more common than necessary in general practice. Methods: We conducted a retrospective chart review of 313 patients who had undergone MRI of the lumbosacral spine during 2014-2015. We recorded and compared various factors, including age, sex, body mass index, current smoking status, race, symptoms, MRI findings, and progression to surgery within the next year. All rates were compared according to whether the MRI results showed radiographically significant findings (MRI-positive) or not (MRI-negative) using the chi-square or Fisher exact tests (if the expected cell count was <5). All analyses were performed using SAS version 9.4. Results: There were no statistically significant differences in the rates of each symptom between the MRI-positive and MRI-negative groups, which accounted for 58.5% (183 of 313) and 41.5% (130 of 313) of the MRIs, respectively. The difference in the rate of surgery in the next year (18% among MRI-positive patients and 8.5% among MRI-negative patients) was found to be statistically significant (p<0.05). Conclusion: Based on our findings, 41.5% of patients underwent lumbar MRI unnecessarily and 81% of patients with positive MRIs did not have surgery within the next year. Further physician training is needed to avoid unnecessary investigations and expenditures.