• Title, Summary, Keyword: T1 Weighted Image

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Quantitative Analysis of T1 Weighted Images due to Change in TI by Using the Inversion Recovery in 3.0T Brain MRI Examination

  • Han, Jung-Seok;Dong, Kyung-Rae;Chung, Woon-Kwan;Cho, Jae-Hwan;Shin, Jae-Woo;Kim, Young-Jae
    • Journal of Magnetics
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    • v.17 no.2
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    • pp.158-162
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    • 2012
  • Although 3.0T magnetic resonance imaging (MRI) has the advantages of a higher signal to noise ratio (SNR) and contrast than 1.5T MRI, there are limitations on the contrast between white and grey matter because of the long T1 recovery time when T1 images are obtained using the Spin Echo Technique. To overcome this, T1 weighted images are obtained occasionally using the inversion recovery (IR) technique, which employs a relatively long TR. The aim of this study was to determine the optimal TI in a brain examination when a T1 weighted image is obtained using the IR technique. Eight participants (male: 7, female: 1, average age: $34{\pm}14.11$) with a normal diagnosis were targeted from February 18, 2012 to February 27, 2012, and the contrast between white and grey matter as well as the contrast to noise ratio (CNRs) in each participant were measured. The CNRs of white matter and grey matter were highest at TI = 600, 650, 750, 900, 1050 and 1100 ms when the TR was 1100, 1400, 1700, 2000, 2300 and 2600 ms, respectively. Therefore, as the TIs were $44.425{\pm}0.877%$ of the TRs in the TR range of 1400-2300 ms, the optimal T1 weighted images that describe the contrast between white and grey matter can be obtained if the TIs are compensated for with $44.425{\pm}0.877%$ of the TRs in the time of setting TIs.

Alveolar Soft Part Sarcoma Metastasized to Both the Skull and the Brain

  • Shin, Tae-Hee;Jung, Young-Jin;Kim, Oh-Lyong;Kim, Min-Su
    • Journal of Korean Neurosurgical Society
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    • v.52 no.1
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    • pp.55-57
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    • 2012
  • Alveolar soft part sarcoma (ASPS) with skull and brain metastases is extremely rare. A 53-year-old patient diagnosed as skull metastasis of ASPS visited our clinic complaining of an outgrowing scalp mass in spite of radiation therapy. Past medical history revealed that the patient had been diagnosed and treated for ASPS of the thigh 4 years ago. Magnetic resonance imaging revealed a hyperintense ovoid mass on the T2-weighted image, an isointense on the T1-weighted image, and a homogeneous enhanced mass with gadolinium. Another small-sized enhanced mass with mild peritumoral swelling was found at the deep white matter of the left frontal lobe. A gross total resection of the skull lesion with cranioplasty was performed for the surgical defect. A histologic examination of the specimens revealed metastatic ASPS involving the skull. Surgery with a total removal of the lesions may be effective for improving a patient's symptoms especially from neurological dysfunction.

Segmentation of MR Brain Image Using Scale Space Filtering and Fuzzy Clustering (스케일 스페이스 필터링과 퍼지 클러스터링을 이용한 뇌 자기공명영상의 분할)

  • 윤옥경;김동휘;박길흠
    • Journal of Korea Multimedia Society
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    • v.3 no.4
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    • pp.339-346
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    • 2000
  • Medical image is analyzed to get an anatomical information for diagnostics. Segmentation must be preceded to recognize and determine the lesion more accurately. In this paper, we propose automatic segmentation algorithm for MR brain images using T1-weighted, T2-weighted and PD images complementarily. The proposed segmentation algorithm is first, extracts cerebrum images from 3 input images using cerebrum mask which is made from PD image. And next, find 3D clusters corresponded to cerebrum tissues using scale filtering and 3D clustering in 3D space which is consisted of T1, T2, and PD axis. Cerebrum images are segmented using FCM algorithm with its initial centroid as the 3D cluster's centroid. The proposed algorithm improved segmentation results using accurate cluster centroid as initial value of FCM algorithm and also can get better segmentation results using multi spectral analysis than single spectral analysis.

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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.

Cerebral Infarction Model in Rat on Magnetic Resonance Imaging (흰 쥐의 뇌경색 병변에 대한 자기공명영상)

  • Jung, Ji-Sung
    • Korean Journal of Digital Imaging in Medicine
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    • v.13 no.2
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    • pp.55-58
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    • 2011
  • It is important to study using experimental animals for research about stroke. Magnetic Resonance Imaging(MRI) is avaluable diagnosticmethods for stroke diagnosis. The purpose of this research is to know the Magnetic Resonance Imaging(MRI) and histopathological characteristics findings after induction of photothrombotic cerebral infarction in rat brain. Male Sprague-Dawley rats were anesthetized, Rose Bengal dye(20 mg/kg) was intravenously injected. The right sensonrimotor cortex of rat brain was exposed to cold light of 7 mm diameter at a position of 1 mm anterior and 3.5 mm lateral to bregma for 20 min. The post-infarction effects were monitored by T1 weighted and T2 weighted images of brain MRI. Histopathological changes were observed after Hematoxylin & Eosin staining. The lesion appeared clearly high signal intensity area on T2 weighted images(the major axis $7.04{\pm}0.11$ mm, the minor axis $3.08{\pm}0.04$ mm) and also H&E staining was same result. In conclusion, MRI was avaluable diagnostic methods for diagnosis and serial changes of stroke.

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Delayed Diagnosis of Probable Radiation Induced Spinal Cord Vascular Disorders

  • Won, Young Il;Kim, Chi Heon;Chung, Chun Kee;Yun, Tae Jin
    • Journal of Korean Neurosurgical Society
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    • v.57 no.3
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    • pp.215-218
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    • 2015
  • Occasionally, unexpected neurological deficits occur after lumbar spinal surgery. We report a case of monoparesis after lumbar decompressive surgery. A 63-year-old man, who had undergone decompression of L4-5 for spinal stenosis 4 days previously in the other hospital, visted the emergency department with progressive weakness in the left leg and hypoesthesia below sensory level T7 on the right side. He had been cured of lung cancer with chemotherapy and radiation therapy 10 years previously, but detailed information of radiotherapy was not available. Whole spine magnetic resonance (MR) imaging showed fatty marrow change from T1 to T8, most likely due to previous irradiation. The T2-weighted MR image showed a high-signal T4-5 spinal cord lesion surrounded by a low signal rim, and the T1-weighted MR image showed focal high signal intensity with focal enhancement. The radiological diagnosis was vascular disorders with suspicious bleeding. Surgical removal was refused by the patient. With rehabilitation, the patient could walk independently without assistance 2 months later. Considering radiation induced change at thoracic vertebrae, vascular disorders may be induced by irradiation. If the spinal cord was previously irradiated, radiation induced vascular disorders needs to be considered.

Distortion of Magnetic Resonance Imaging for Different Types of Orthodontic Material (치과 교정 물질에 따른 자기공명영상의 왜곡)

  • Song, Hyun-Og;Lim, Cheong-Hwan;Lee, Sang-Ho;Yang, Oh-Nam;Baek, Chang-Moo;Jung, Hong-Ryang
    • Journal of Digital Convergence
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    • v.12 no.2
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    • pp.439-446
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    • 2014
  • To evaluate the effects of an artifact by metal material for orthodontics in Magnetic Resonance Image (MRI) examination, wires and brackets used in orthodontics were selected and compared. Using a head coil, a $T_2$-weighted image, $T_1$-weighted image and FLAIR image were obtained. With obtained images, the sizes of the artifacts were measured and compared using Image J Program. In the research, the material with the biggest artifact in the wires and brackets for orthodontics was stainless steel wire. In the future, selecting and developing metal for correction should be considered also in other fields along with the purpose of orthodontics.

Focal Lesion Detection of SPIO-specific agent Compared with Optimized Pulse Sequences in the Hepatic Metastases: Case Review (간 전이환자에서 최적의 펄스시퀀스에 따른 SPIO 특이성 조영제의 국소병변검출: Case review)

  • Goo, Eun-Hoe
    • Korean Journal of Digital Imaging in Medicine
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    • v.14 no.2
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    • pp.57-61
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    • 2012
  • To compare the accuracy of breath-hold magnetic resonance imaging sequences to establish the most effective superparamagnetic iron oxide-enhanced sequence for detection of hepatic metastases. A total of 100 patients(50men and 50women, mean age: 60years) with liver disease(including malignant and benign liver lesions) were investigated at 3.0T machine (GE, General Electric Medical System, Excite HD) with 8Ch body coil. Pulse sequence for MR imaging decided to the FS-T2-FSE-RT(TR/TE/Thick./Freq./Phase=12857ms/100ms/7mm/512/384), MGRE(TR/TE/Thick./Freq./Phase=100ms/9.7ms/7mm/384/288), in-out of phase echo(TR/$TE_1$, $TE_2$/Thick./Freq./Phase=140ms/2.4, 5.8ms/7mm/352/300), Images obtained before the injection of SPIO. Six sequences were optimized for lesion detection: FS-T2-FSE-RT, multigradient recalled echo data image(MGRE), T2-weighted MGRE with an 9.7msec echo time. Images were reviewed independently by five blinded observers. The accuracy of each sequence was measured by using picture archiving communication system analysis. All results were correlated with findings at multidectator computed tomography examination. Differences between the mean results of the six observers were measured by using paired student t-test analysis. Postcontrast T2-weighted MGRE sequences were the most accurate and were significantly superior to postcontrast FS-T2-FSE-RT, T2-weighted MGRE, in-out of phase MR sequences(p < .05). For all lesions that were malignant or smaller than 1 cm, respectively, contrast to noise ratio of pre and postcontrast sequences were -1and -0.3 for T2-weighted FSE, 0.53 and 4.5 in-out of phase, 7, 7.08, 5.08, 3.32, 1.7, 1.16, 0.79, 0.68 for GRE with 2.9, 7.5, 12.1, 16.6, 21.2, 25.8, 30.4, 35.0 TE values. Breath-hold various TE precontrast sequences offer improvement in sensitivity compared with fixed multigradient recalled echo sequences alone.

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Arachnoid Granulations Mimicking Multiple Osteolytic Bone Lesions in the Occipital Bone

  • Park, Seong-Hyun;Park, Ki-Su;Hwang, Jeong-Hyun
    • Brain Tumor Research and Treatment
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    • v.6 no.2
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    • pp.68-72
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    • 2018
  • We report a rare case of arachnoid granulations mimicking multiple osteolytic bone lesions. A 66-year-old woman was admitted to a local clinic for a regular checkup. Upon admission, brain CT showed multiple osteolytic lesions in the occipital bone. These needed to be differentiated from multiple osteolytic bone tumor. Subsequent brain MRI revealed that the osteolytic lesions were isointense to cerebrospinal fluid, hyperintense on T2-weighted image, hypointense on T1-weighted image, and with subtle capsules around the osteolytic lesions that were visible after gadolinium injection. A bone scan revealed no radiotracer uptake. The lesions were in both the transverse sinuses and the torcular herophili. With typical radiological appearances of the lesions, the osteolytic lesions were diagnosed as multiple arachnoid granulations. No further treatment was planned. A 1-year follow-up brain CT scan revealed no change. We should consider the possibility of arachnoid granulations when multiple osteolytic lesions are observed in the occipital bone.

MAGNETIC RESONANCE IMAGING APPEARANCE OF EPIDURAL HEMATOMA IN DOG (개의 경막외 혈종의 자기공명영상학적 진단)

  • Choi, Chi-Bong;Kim, Hwi-Yool;Kim, Su-Gwan;Bae, Chun-Sik
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.27 no.5
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    • pp.488-491
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    • 2005
  • A 3-year-old female, 5kg, Shih-tzu developed an acute onset of depression, disorientation, hypersalivation, nystagmus after falling down 2 meter height place. In plain skull radiography, there was fracture line in the frontal and parietal bones and next day magnetic resonance imaging examination was performed. Magnetic resonance imaging of the brain was performed with 3.0 Tesla unit. Under general anesthesia, the dog was placed in prone with its head positioned in a birdcage coil. Transverse, sagittal and coronal fast spin echo images of the brain were obtained with the following pulse sequences: T1 weighted images (TR = 560 ms and TE = 18.6 ms) and T2 weighted images (TR = 3500 ms and TE = 80 ms). Magnetic resonance imaging showed epidural hematoma in the left frontal area resulting in compression of the adjacent brain parenchyma. Left lateral ventricle was compressed secondarily and the longitudinal fissure shifted to the right, representing mass effect. The lesion was iso-to slightly hyperintense on T1 weighted image and iso-slightly hypointense signal on T2 weighted image. At necropsy, there was a skull fracture and epidural hematoma in the left frontal area. Magnetic resonance imaging of epidural hematoma is reviewed.