• Title, Summary, Keyword: T1 Weighted Image

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The quantitative analysis of Diffusion Weighted Imaging in Breast MRI (유방 MRI 검사에서 확산강조영상의 정량적 분석)

  • Cho, Jae-Hwan;Kim, Hyeon-Ju;Hong, Yin-Sik;Lee, Hae-Kag
    • Journal of the Korean Society of Radiology
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    • v.5 no.3
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    • pp.149-154
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    • 2011
  • The purpose of this study was to examine the usefulness of diffusion weighted images in breast MRI by performing a quantitative comparative analysis in patients diagnosed with DCIS. On a 3.0T MR scanner, diffusion weighted images and ADC map images were obtained from 20 patients histologically diagnosed with ductal carcinoma in situ (DCIS). The findings from the quantitative image analysis are the following: The diffusion weighted images showed higher SNR and CNR at the lesion area. In addition, the ADC values were lower at the lesion area.

Cavernous Hemangioma in the Middle Cranial Fossa & Cavernous Sinus

  • Park, Chang-Kyu;Lee, Mou-Seop;Kim, Young-Gyu;Kim, Dong-Ho
    • Journal of Korean Neurosurgical Society
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    • v.40 no.4
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    • pp.277-280
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    • 2006
  • Extracerebral cavernous hemangiomas are rare vascular tumors that are very difficult to remove because of severe intraoperative bleeding. We report a case of 57-year-old male with extracerebral cavernous hemangioma with review of 126 cases in the literature. Patient presented with blurred vision, diplopia, numbness on the left side of his face. Magnetic resonance imaging revealed a well defined mass of $3{\times}4{\times}3cm$ size with heterogenous iso-or hypointensity on T1-weighted image showing strong homogenous contrast enhancement and marked hyperintensity on T2-weighted image. Digital subtraction angiography[DSA] revealed a faint tumor blush by feeders from the left internal carotid artery[ICA] and left external carotid artery[ECA] in the delayed phase. Even with profuse intratumoral bleeding, near total removal was achieved. In addition to preoperative neurologic deficits such as ophthalmoplegia, facial numbness in the V1-2 dermatomes, ptosis appeared postoperatively.

Measurement of Cerebral Blood Volume and Relative Perfusion Rate Mapping Using MR Imaging in Cats

  • Park Byung-Rae;Shin Yong-Wong
    • Biomedical Science Letters
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    • v.10 no.4
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    • pp.515-521
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    • 2004
  • To measure regional cerebral blood volume (rCBV) with perfusion MR imaging of cerebral fat embolism by neutral fat and free fatty acids in cats. Triolein (group 1, n=15), oleic acid (group 2, n=9) and linoleic acid (group 3, n=11) were infused into unilateral internal carotid artery using microcatheter through the transfemoral approach. PVA particle was used as a non-fat embolic material in a control group (group 4, n=9). Perfusion-weighted MR image was obtained at 30 minutes and 2 hours postembolization, based on T2-and diffusion-weighted images. The data of lesion and contralateral normal area were transferred to personal computer, time-to-signal intensity curve was drawn and trans for used to △R2/sup */ curve in regular order. The process in the personal computer was done by using the author's developmental image processing program and interactive data language (IDL) softwares. Statistical significance was approved by paired t-test and ANOVA. rCBV of the lesion was decreased comparing to the normal area in all groups. The ratios of rCBV were as follows (group No, at 30 minutes, at 2 hours); group 1,32%, 51%; group 2, 30%, 44%; group 3, 39%, 61%; group 4, 21%, 36%. rCBVs of 2 hours was significantly increased compared to those of 30 minutes in all groups (P<0.005). rCBV was decreased at 30 minutes in cerebral fat embolism and recovered a little, but significantly at 2 hours. Perfusion-weighted images was useful method in offering hemodynamic information in cerebral fat embolism.

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High Signal Intensities on T1-Weighted MRI as a Biomarker of Manganese

  • Kim, Yang-Ho
    • Proceedings of the Korean Environmental Health Society Conference
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    • pp.105-139
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    • 2005
  • Increased signal in T1-weighted images was observed in the experimental manganese (Mn) poisoning of the non-human primate and a patient with Mn neurointoxication. However, our study showed that the increased signals in magnetic resonance images (MRI) were highly prevalent (41.6%) in Mn-exposed workers. Blood Mn concentration correlated with pallidal index. These changes in MRI tend to disappear following the withdrawal from the source of Mn accumulation, despite permanent neurological damage. Thus increased signal intensities on a T1-weighted image reflect exposure to Mn, but not necessarily manganism. Our study also showed that the concentration of Mn required to produce increased signal intensities on MRI is much lower than the threshold necessary to result in overt clinical signs of manganism. Increased signal intensities in the globus pallidus were determined by manganese accumulation in the animal experiment. Reanalysis of the previous data with the structural equation model revealed that pallidal index (Pl) on MRI reflects target organ dose of occupational Mn exposure

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Evaluation of Usefulness of IDEAL(Iterative decomposition of water and fat with echo asymmetry and least squares estimation) Technique in 3.0T Breast MRI (3.0T 자기공명영상을 이용한 유방 검사시 IDEAL기법의 유용성 평가)

  • Cho, Jae-Hwan
    • Journal of Digital Contents Society
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    • v.11 no.2
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    • pp.217-224
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    • 2010
  • The purpose of this study was to examine the usefulness of IDEAL technique in breast MRI by performing a quantitative comparative analysis in patients diagnosed with DCIS. On a 3.0T MR scanner, fat-suppressed T2-weighted images and T1-weighted images before and after contrast enhancement were obtained from 20 patients histologically diagnosed with ductal carcinoma in situ (DCIS). The findings from the quantitative image analysis are the following: 1) On T2-weighted images, SNR were not significantly different in the lesion area itself between the CHESS and IDEAL groups, while the IDEAL group showed higher SNR at the ductal area and fat area than the CHESS group. In addition, the CNR were higher for the IDEAL group in those regions. 2) On T1-weighted images before enhancement, SNR were not significantly different in the lesion area itself between the CHESS and IDEAL groups, while the IDEAL group showed higher SNR at the ductal area and fat area than the CHESS group. In addition, the CNR were higher for the IDEAL group in those regions. 3) On T1-weighted images after enhancement, SNR were not significantly different in the lesion area itself between the CHESS and IDEAL groups, while the IDEAL group showed higher SNR at the ductal area and fat area than the CHESS group.

Measurement of Apparent Diffusion Coefficient Values from Diffusion-Weighted MRI: A Comparison of Manual and Semiautomatic Segmentation Methods

  • Kim, Seong Ho;Choi, Seung Hong;Yoon, Tae Jin;Kim, Tae Min;Lee, Se-Hoon;Park, Chul-Kee;Kim, Ji-Hoon;Sohn, Chul-Ho;Park, Sung-Hye;Kim, Il Han
    • Investigative Magnetic Resonance Imaging
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    • v.19 no.2
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    • pp.88-98
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    • 2015
  • Purpose: To compare the interobserver and intraobserver reliability of mean apparent diffusion coefficient (ADC) values using contrast-enhanced (CE) T1 weighted image (WI) and T2WI as structural images between manual and semiautomatic segmentation methods. Materials and Methods: Between January 2011 and May 2013, 28 patients who underwent brain MR with diffusion weighted image (DWI) and were pathologically confirmed as having glioblastoma participated in our study. The ADC values were measured twice in manual and semiautomatic segmentation methods using CE-T1WI and T2WI as structural images to obtain interobserver and intraobserver reliability. Moreover, intraobserver reliabilities of the different segmentation methods were assessed after subgrouping of the patients based on the MR findings. Results: Interobserver and intraobserver reliabilities were high in both manual and semiautomatic segmentation methods on CE-T1WI-based evaluation, while interobserver reliability on T2WI-based evaluation was not high enough to be used in a clinical context. The intraobserver reliability was particularly lower with the T2WI-based semiautomatic segmentation method in the subgroups with involved $lobes{\leq}2$, with partially demarcated tumor borders, poorly demarcated inner margins of the necrotic portion, and with perilesional edema. Conclusion: Both the manual and semiautomatic segmentation methods on CE-T1WI-based evaluation were clinically acceptable in the measurement of mean ADC values with high interobserver and intraobserver reliabilities.

A Effectiveness of Multi-Transmit Parallel Technique on Magnetic Resonance Imaging of FOV Less Than 26cm (자기공명영상검사 시 26cm 이하 영상영역의 Multi-Transmit 기법의 유용성)

  • Son, Soon-Yong;Choi, Kwan-Woo;Park, Kyeong-Jin;Lee, Jong-Seok;Yoo, Beong-Gyu
    • Journal of radiological science and technology
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    • v.38 no.4
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    • pp.429-435
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    • 2015
  • The purpose of this study was to prospectively estimate the effectiveness of multi-transmit parallel technique in reduced FOV(Field of View) less than 26 cm. Homogeneity, SNR(signal to noise ratio) and acquisition time were measured and compared by setting FOV less than 26cm on the T1 and T2 weighted images using ACR phantom. The multi-transmit parallel technique resulted in significantly faster image acquisition by 46.8 % in T1 weighted images and 18.9% in T2 weighted images. The homogeneity and SNR values had no significant difference between pre and post application of the multi-transmit parallel technique. In conclusion, this study demonstrates the feasibility of multi-transmit parallel technique in FOV less than 26cm with a rapid acquisition and maintained image quality.

A Case of Recurrent Dermatofibrosarcoma of the Scalp

  • Jo, Tae-Yeon;Kim, Sang-Dae;Kim, Se-Hoon;Park, Jung-Yul
    • Journal of Korean Neurosurgical Society
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    • v.37 no.3
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    • pp.241-243
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    • 2005
  • We report a case of recurrent dermatofibrosarcoma in a 30-years-old woman who had undergone operations three times during 60 months and had received post-operative radiotherapy. On neurological examination, no neurological deficits were noticed. In brain magnetic resonance image(MRI), there was right parieto-occipital scalp mass with high signal in T2-weighted image, low signal in T1-weighted image with homogeneous enhancement. The removal was done including about 2cm uninvolved margins and pathologic examination of the lesion revealed dermatofibrosarcoma protuberans(DFSP). The prognostic factors of local recurrence may be related to surgical margins for resection; the length from the grossly intact margins, and the microscopically controlled excision in margins.

Evaluation of Modified Turbo Spin Echo Technique Compared with Double Inversion Recovery Technique in Acquisition of Black Blood Brain Vessel Image

  • Choi, Kwan-Woo;Lee, Ho-Beom;Na, Sa-Ra;Son, Soon-Yong
    • Journal of Magnetics
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    • v.21 no.1
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    • pp.148-152
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    • 2016
  • The main goal was to evaluate effectiveness of a modified TSE sequence compared with DIR (double inversion recovery) sequence in acquisition of fast flow brain vessel images using signal void effect. 32 healthy volunteers (10 men and 22 women; mean age of 31 years; ranging between 28-43 years) who underwent black blood DIR sequence (group A) and the modified TSE sequence (group B) were enrolled in our study. Signal to Noise Ratio (SNR) and Contrast to Noise Ratio (CNR) of the internal carotid arteries' lumen were compared in T1 and T2 weighted images for both group A and B. The images obtained from group B showed lower SNR values in internal carotid artery than the group A in both of the T1 and T2 weighted images (11.49% and 13.66% respectively). While the CNR values were higher in the group B than the group A in both of the T1 and T2 weighted images (8.69% and 7.55 % respectively). The qualitative score of all categories were not significantly different between the two groups. Furthermore approximately 49% of the total scan time was reduced from group B. Our study is to shorten the scanning time and minimize the inconveniences of the patients in acquisition of the black blood images of brain by using the signal void effect in the modified TSE technique while keeping the diagnostic value of the test.