• Title/Summary/Keyword: Magnetic resonance imaging (MR)

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T2 Relaxation Times of the Cingulate Cortex, Amygdaloid Body, Hippocampal Body, and Insular Cortex: Comparison of 1.5 T and 3.0 T (대상회 피질, 편도체, 해마체, 도피질의 T2 이완시간: 1.5테슬러와 3.0테슬러 자기공명영상장치의 비교)

  • Lee, Ho-Joon;Kim, Eung-Yeop
    • Investigative Magnetic Resonance Imaging
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    • v.15 no.1
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    • pp.67-71
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    • 2011
  • Purpose : To compare T2 relaxation times (T2) in the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex between 1.5T and 3.0T MR imagers. Materials and Methods : Twelve healthy volunteers underwent FLAIR and CPMG imaging perpendicular to the hippocampal body at both 3.0T and 1.5T. T2 was measured in the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex. The T2 relaxation time ratios of the cingulate cortex, insular cortex, and amygdaloid body to the hippocampal body were compared between 1.5T and 3.0T. Results : The mean T2 of the cingulate cortex, amygdaloid body, hippocampal body, and insular cortex at 1.5T were $109.5{\pm}3.1$, $117.0{\pm}7.1$, $114.7{\pm}2.4$, and $111.3{\pm}2.4$, respectively; $99.7{\pm}3.8$, $100.7{\pm}4.3$, $97.9{\pm}3.4$, and $96.2{\pm}2.0$, respectively, at 3.0T. Percentage changes of T2 in the cingulate cortex, insular cortex, amygdaloid body, and hippocampal body at 3.0T with respect to those at 1.5T were -8.9%, -13.5%, -14.6%, and -13.5%, respectively. The mean T2 ratios of the cingulate gyrus, insular cortex, and amygdaloid body to the hippocampal body at 1.5T and 3.0T were 0.96 and 1.02 (p = 0.003); 1.02 and 1.03 (p>0.05); 0.97 and 0.98 (p>0.05), respectively. Conclusion : T2 decrease in the cingulate cortex was less than the amygdaloid body, insular cortex, and hippocampal body at 3.0T. The mean T2 ratio of the cingulate gyrus to the hippocampal body was significantly different between 1.5T and 3.0T.

Analysis of Image Distortion on Magnetic Resonance Diffusion Weighted Imaging

  • Cho, Ah Rang;Lee, Hae Kag;Yoo, Heung Joon;Park, Cheol-Soo
    • Journal of Magnetics
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    • v.20 no.4
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    • pp.381-386
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    • 2015
  • The purpose of this study is to improve diagnostic efficiency of clinical study by setting up guidelines for more precise examination with a comparative analysis of signal intensity and image distortion depending on the location of X axial of object when performing magnetic resonance diffusion weighted imaging (MR DWI) examination. We arranged the self-produced phantom with a 45 mm of interval from the core of 44 regent bottles that have a 16 mm of external diameter and 55 mm of height, and were placed in 4 rows and 11 columns in an acrylic box. We also filled up water and margarine to portrait the fat. We used 3T Skyra and 18 Channel Body array coil. We also obtained the coronal image with the direction of RL (right to left) by using scan slice thinkness 3 mm, slice gap: 0mm, field of view (FOV): $450{\times}450mm^2$, repetition time (TR): 5000 ms, echo time (TE): 73/118 ms, Matrix: $126{\times}126$, slice number: 15, scan time: 9 min 45sec, number of excitations (NEX): 3, phase encoding as a diffusion-weighted imaging parameter. In order to scan, we set b-value to $0s/mm^2$, $400s/mm^2$, and $1,400s/mm^2$, and obtained T2 fat saturation image. Then we did a comparative analysis on the differences between image distortion and signal intensity depending on the location of X axial based on iso-center of patient's table. We used "Image J" as a comparative analysis programme, and used SPSS v18.0 as a statistic programme. There was not much difference between image distortion and signal intensity on fat and water from T2 fat saturation image. But, the average value depends on the location of X axial was statistically significant (p < 0.05). From DWI image, when b-value was 0 and 400, there was no significant difference up to $2^{nd}$ columns right to left from the core of patient's table, however, there was a decline in signal intensity and image distortion from the $3^{rd}$ columns and they started to decrease rapidly at the $4^{th}$ columns. When b-value was 1,400, there was not much difference between the $1^{st}$ row right to left from the core of patient's table, however, image distortion started to appear from the $2^{nd}$ columns with no change in signal intensity, the signal was getting decreased from the $3^{rd}$ columns, and both signal intensity and image distortion started to get decreased rapidly. At this moment, the reagent bottles from outside out of 11 reagent bottles were not verified from the image, and only 9 reagent bottles were verified. However, it was not possible to verify anything from the $5^{th}$ columns. But, the average value depends on the location of X axial was statistically significant. On T2 FS image, there was a significant decline in image distortion and signal intensity over 180mm from the core of patient's table. On diffusion-weighted image, there was a significant decline in image distortion and signal intensity over 90 mm, and they became unverifiable over 180 mm. Therefore, we should make an image that has a diagnostic value from examinations that are hard to locate patient's position.

Neuro-Anatomical Evaluation of Human Suitability for Rural and Urban Environment by Using fMRI (자연과 도시환경의 인체친화성에 대한 신경해부학적 평가: 기능적 자기공명영상법)

  • Kim, Gwang-Won;Song, Jin-Kyu;Jeong, Gwang-Woo
    • Progress in Medical Physics
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    • v.22 no.1
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    • pp.18-27
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    • 2011
  • The purpose of this study was to identify different cerebral areas of the human brain associated with rural and urban picture stimulation using a 3.0 Tesla functional magnetic resonance imaging (fMRI) and further to investigate the human suitability for rural and urban environments. A total of 27 right-handed participants (mean age: $27.3{\pm}3.7$) underwent fMRI study on a 3.0T MR scanner. The brain activation patterns were induced by visual stimulation with each rural and urban sceneries. The participants were divided into two groups as 26 subjects favorable to rural scenery and 14 subjects unfavorable to urban scenery based on their filled-in questionnaire. The differences of the brain activation in response to two extreme types of pictures by the two sample t-test were characterized as follows: the activation areas observed in rural scenery over urban were the insula, middle frontal gyrus, precuneus, caudate nucleus, superior parietal gyrus, superior occipital gyrus, fusiform gyrus, and globus pallidus. In urban scenery over rural, the inferior frontal gyrus, parahippocampal gyrus, postcentral gyrus, superior temporal gyrus, amygdala, and posterior cingulate gyrus were activated. The fMRI patterns also clearly show that rural scenery elevated positive emotion such as happiness and comfort. On the contrary, urban scenery elevated negative emotion, resulting in activation of the amygdala which is the key region for the feelings of fear, anxiety and unpleasantness. This study evaluated differential cerebral areas of the human brain associated with rural and urban picture stimulation using a 3.0 Tesla fMRI. These findings will be useful as an objective evaluation guide to human suitability for ecological environments that are related to brain activation with joy, anger, sorrow and pleasure.

Mucoid Degeneration of Anterior Cruciate Ligament: Correlation between MR Imaging and Pathologic Findings in Patients with Osteoarthritis of the Knee (앞십자 인대의 점액 변성: 슬관절 퇴행성 관절염 환자에서 MRI 소견과 병리소견의 연관)

  • Ryu, Jeong-Ah;Liew, Hyun-Jeong;Kim, Sung-Moon;Shin, Myung-Jin;Shin, Hee-Jung;Cho, Kyung-Ja;Cho, Woo-Shin;Kang, Chang-Ho;Lee, Min-Hee;Kim, Mi-Sung;Park, Noh-Hyuck;Lee, Sang-Hoon
    • Investigative Magnetic Resonance Imaging
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    • v.11 no.1
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    • pp.27-32
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    • 2007
  • Purpose : To evaluate the mucoid degeneration (MD) of the anterior cruciate ligament (ACL) of the knee by correlation of MRI findings with pathology, in the patients with osteoarthritis (OA). Materials and Methods : This study included 17 patients (mean 68.8 years old) who underwent preoperative MRI. In proton density-weighted sagittal and coronal images ACLs were evaluated for the thickness and signal intensity (SI). Total knee replacement arthroplasty was performed and the pathologic findings of ACL were evaluated. MD was classified as 3 grades according to the degenerated amount in microscopy. Thickness and SI was evaluated as normal or increased on MRI. Results : All of the 4 patients who showed thickened ACL showed increased SI on MRI. All of the 8 patients with increased SI of the ACL on MRI had MD in the ACL. However, remained 9 patients also had MD, in spite of their normal thickness and SI on MRI. Calcification was seen in 5 patients. Conclusion : Eight cases who showed ACL thickening or increased SI on MRI were well correlated with MD, however, because the other nine cases who showed normal thickness and normal SI of ACL on MRI also showed MD in pathology, normal MRI finding should not exclude the possibility of MD of ACL.

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Tc-99m ECD Brain SPECT in MELAS Syndrome and Mitochondrial Myopathy: Comparison with MR findings (MELAS 증후군과 미토콘드리아 근육병에서의 Tc-99m ECD 뇌단일 광전자방출 전산화단층촬영 소견: 자기공명영상과의 비교)

  • Park, Sang-Joon;Ryu, Young-Hoon;Jeon, Tae-Joo;Kim, Jai-Keun;Nam, Ji-Eun;Yoon, Pyeong-Ho;Yoon, Choon-Sik;Lee, Jong-Doo
    • The Korean Journal of Nuclear Medicine
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    • v.32 no.6
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    • pp.490-496
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    • 1998
  • Purpose: We evaluated brain perfusion SPECT findings of MELAS syndrome and mitochondrial myopathy in correlation with MR imaging in search of specific imaging features. Materials and Methods: Subjects were five patients (four females and one male; age range, 1 to 25 year) who presented with repeated stroke-like episodes, seizures or developmental delay or asymptomatic but had elevated lactic acid in CSF and serum. Conventional non-contrast MR imaging and Tc-99m-ethyl cysteinate dimer (ECD) brain perfusion SPECT were Performed and imaging features were analyzed. Results: MRI demonstrated increased T2 signal intensities in the affected areas of gray and white matters mainly in the parietal (4/5) and occipital lobes (4/5) and in the basal ganglia (1/5), which were not restricted to a specific vascular territory. SPECT demonstrated decreased perfusion in the corresponding regions of MRI lesions. In addition, there were perfusion defects in parietal (1 patient), temporal (2), and frontal (1) lobes and basal ganglia (1) and thalami (2). In a patient with mitochondrial myopathy who had normal MRI, decreased perfusion was noted in left parietal area and bilateral thalami. Conclusion: Tc-99m ECD SPECT imaging in patients with MELAS syndrome and mitochondrial myopathy showed hypoperfusion of parieto-occipital cortex, basal ganglia, thalamus and temporal cortex, which were not restricted to a specific vascular territory. There were no specific imaging features on SPECT. The significance of abnormal perfusion on SPECT without corresponding MR abnormalities needs to be evaluated further in larger number of patients.

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Biceps Femoris Tendon and Lateral Collateral Ligament: Analysis of Insertion Pattern Using MRI (대퇴이두건과 외측 측부인대: 자기공명영상을 이용한 부착형태 유형의 분석)

  • Shin, Yun Kyung;Ryu, Kyung Nam;Park, Ji Seon;Lee, Jung Eun;Jin, Wook;Park, So Young;Yoon, So Hee;Lee, Kyung Ryeol
    • Investigative Magnetic Resonance Imaging
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    • v.18 no.3
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    • pp.225-231
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    • 2014
  • Purpose : The biceps femoris tendon (BFT) and lateral collateral ligament (LCL) in the knee were formerly known to form a conjoined tendon at the fibular attachment site. However, the BFT and LCL are attached into the fibular head in various patterns. We classified insertion patterns of the BFT and LCL using MR imaging, and analyzed whether the LCL attaches to the fibular head or not. Materials and Methods: A total of 494 consecutive knee MRIs of 470 patients taken between July 2012 and December 2012 were retrospectively reviewed. There were 224 males and 246 females, and patient age varied from 10 to 88 (mean, 48.6). The exclusion criteria were previous surgery and poor image quality. Using 3T fat-suppressed proton density-weighted axial images, the fibular insertion patterns of the BFT and LCL were classified into following types: type I (the LCL passes between the anterior arm and direct arm of the BFT's long head), type II (the LCL joins with anterior arm of the long head of the BFT), type III (the BFT and LCL join to form a conjoined tendon), type IV (the LCL passes laterally around the anterior margin of the BFT), and type V (the LCL passes posteriorly to the direct arm of the BFT's long head). Results: Among the 494 cases of the knee MRI, there were 433 (87.65%) type I cases, 21 (4.25%) type II cases, 2 (0.4%) type III cases, 16 (3.23%) type IV cases, and 22 (4.45%) type V cases. There were 26 cases (5.26%) in which the LCL and BFT were not attached into the fibular head. Conclusion: The fibular attachment pattern of the BFT and LCL shows diverse types in MR imaging. The LCL does not adhere to the head in some patients.

Evaluation of Cardiac Ejection Fraction using Cardiac MRI (Cardiac MRI를 이용한 심박출계수의 평가)

  • Eun, Sung-Jong;Kook, Jin-Sun
    • Journal of the Korean Society of Radiology
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    • v.5 no.5
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    • pp.289-294
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    • 2011
  • The aim of this study is to evaluate the differences of ejection fraction of left ventricle through the quantitative analysis of diastolic and systolic volumes according to slices selected using cardiac MR imaging. A total of 12 volunteers (7 normal, 1 myocardium bridge, and 4 arrhythmia) underwent cardiac MRI on a MR scanner(Magnetom Trio, Siemens, Germany). Ejection fractions for quantitative analysis were calculated at single slice of center of left ventricle, 3, 5, and 6-7 slices extending from the center of left ventricle. Average values were analyzed for evaluating differences of ejection fraction according to the number of slices selected. Mean value of normal person of ejection fraction were 67.14% at single slice of center of left ventricle, 66.24% at 3 slices, 65.63% at 5 slices, and 65.29% at 6-7 slices. While ejection fraction obtained from a patient with 61.74% at single slice of center of left ventricle, 60.92% at 3 slices, 60.89% at 5 slices, and 61.89% at 6-7 slices. There was no significant differences by the number of slices selected. This study demonstrates that ejection fraction obtained from single slice of center of left ventricle may represent a optimum parameter for cardiac function, instead of the value calculated on the variable slices selected.

Clinical Analysis of Spinal Cord Hemangioblastoma (척수 혈관모세포종의 임상 분석)

  • Lee, Dae Kyu;Choe, Woo Jin;Kim, Dong Yoon;Lee, Chul Hee;Chung, Chun Kee;Kim, Hyun Jib
    • Journal of Korean Neurosurgical Society
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    • v.30 no.11
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    • pp.1291-1299
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    • 2001
  • Objectives : The authors present a retrospective analysis of 14 patients treated for spinal cord hemangioblastoma (SCH) between Dec. 1986 and Mar. 2000. This study was conducted to evaluate and compare the difference of the functional outcomes associated with the extent of surgical removal of SCH. Methods : Eleven patients were male and three patients were female. Their mean age was 37.2 years that ranged from 19 to 62 years. Preoperative magnetic resonance(MR) imaging of the spine was performed in all cases, and preoperative angiography in eleven cases. They were followed from 15 months to 161 months(median follow-up period, 47 months), and we investigated the change of neurological symptoms and functional outcomes with radiological features, especially on MR imaging. Results : Six patients were accompanied by von Hippel-Lindau disease, and three of them had multiple CNS tumors. Thirteen patients had intramedullary tumor, and the remaining one had extradural. Syringomyelia around the tumor was observed in ten cases. All patients underwent surgical removal, and gross total removal(GTR) was achieved in ten cases. Preoperative embolization was performed in four cases. In four patients who were treated with preoperative embolization, intraoperative loss of blood was minimal and GTR was possible. One patient developed a transient swallowing difficulty postoperatively without permanent postoperative neurological deficits. In three of four patients in whom GTR was not possible, their functional outcomes were worsened postoperatively. The functional status at discharge was improved in seven patients, stationary in four patients, and worse in three. At the last follow-up(15-161 months), one of four patients who had been stationary at discharge showed improvement but, the rest did not show any change. All patients who showed neurological improvement were patients with GTR, and the patients with GTR had significant better outcome than those without GTR(p=0.015). Conclusion : Surgical treatment, and especially, GTR is considered as treatment of choice for spinal cord hemangioblastoma. Preoperative embolization may prevent intraoperative bleeding and improve surgical outcome.

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Medical Image Compression Using JPEG International Standard (JPEG 표준안을 이용한 의료 영상 압축)

  • Ahn, Chang-Beom;Han, Sang-Woo;Kim, Il-Yoen
    • Proceedings of the KIEE Conference
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    • 1993.07a
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    • pp.504-506
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    • 1993
  • The Joint Photographic Experts Group (JPEG) standard was proposed by the International Standardization Organization (ISO/SC 29/WG 10) and the CCITT SG VIII as an international standard for digital continuous-tone still image compression. The JPEG standard has been widely accepted in electronic imaging, computer graphics, and multi-media applications, however, due to the lossy character of the JPEG compression its application in the field of medical imaging has been limited. In this paper, the JPEG standard was applied to a series of head sections of magnetic resonance (MR) images (256 gray levels, $256{\times}256$ size) and its performance was investigated. For this purpose, DCT-based sequential mode of the JPEG standard was implemented using the CL550 compression chip and progressive and lossless coding was implemented by software without additional hardware. From the experiment, it appears that the compression ratio of about 10 to 20 was obtained for the MR images without noticeable distortion. It is also noted that the error signal between the reconstructed image by the JPEG and the original image was nearly random noise without causing any special-pattern-related artifact. Although the coding efficiency of the progressive and hierarchical coding is identical to that of the sequential coding in compression ratio and SNR, it has useful features In fast search of patient Image from huge image data base and in remote diagnosis through slow public communication channel.

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Expert Opinions and Recommendations for the Clinical Use of Quantitative Analysis Software for MRI-Based Brain Volumetry (뇌 자기공명영상 뇌용적 분석 소프트웨어의 임상적 적용에 대한 전문가 의견과 권고안)

  • Ji Young Lee;Ji Eun Park;Mi Sun Chung;Se Won Oh;Won-Jin Moon;Aging and Neurodegeneration Imaging (ANDI) Study Group, Korean Society of Neuroradiology (KSNR)
    • Journal of the Korean Society of Radiology
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    • v.82 no.5
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    • pp.1124-1139
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    • 2021
  • The objective assessment of atrophy and the measurement of brain volume is important in the early diagnosis of dementia and neurodegenerative diseases. Recently, several MR-based volumetry software have been developed. For their clinical application, several issues arise, including the standardization of image acquisition and their validation of software. Additionally, it is important to highlight the diagnostic performance of the volumetry software based on expert opinions. We instituted a task force within the Korean Society of Neuroradiology to develop guidelines for the clinical use of MR-based brain volumetry software. In this review, we introduce the commercially available software and compare their diagnostic performances. We suggest the need for a standard protocol for image acquisition, the validation of the software, and evaluations of the limitations of the software related to clinical practice. We present recommendations for the clinical applications of commercially available software for volumetry based on the expert opinions of the Korean Society of Neuroradiology.