• Title, Summary, Keyword: T1 Weighted Image

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The Comparative Analysis Study and Usability Assessment of Fat Suppressed 3D T2* weighted Technique and Fat Suppressed 3D SPGR Technique when Examining MRI for Knee Joint Cartilage Assesment (슬관절 연골 평가를 위한 자기공명영상 검사 시 지방 신호 억제 3D T2* Weighted 기법과 지방 신호 억제 3D SPGR 기법의 비교 및 유용성 평가)

  • Kang, Sung-Jin
    • Journal of the Korean Magnetics Society
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    • v.26 no.6
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    • pp.219-225
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    • 2016
  • In this study, for assessment of degenerative knee joint cartilage disease we acquired images by fat suppressed 3D spoiled gradient recalled (SPGR) and fat suppressed 3D $T2^*$ weighted imaging techniques. To do a quantitative evaluation, the knee joint cartilage was divided into medial femoral cartilage (MFC), medial tibial cartilage (MTC), lateral femoral cartilage (LFC), lateral femoral cartilage (LFC) and patella cartilage (Pat) to measure their respective signal intensity values, signal-to-noise ratio, and contrast-to-noise ratio. As for the measured values, statistical significance between two techniques was verified by using Mann-Whitney U-Test. To do a qualitative evaluation, two radiologists have examined images by techniques after which image artifact, cartilage surface, tissue contrast, and depiction of lesion distinguishing were evaluated based on 4-point scaling (1: bad, 2: appropriate, 3: good, 4: excellent), and based on the result, statistical significance was verified by using Kappa-value Test. 3.0T MR system and HD T/R 8ch knee array coil were used to acquire images. As a result of a quantitative analysis, based on SNR values measured by using two imaging techniques, MFC, LFC, LTC, and Pat showed statistical significance (p < 0.05), but MTC did not (p > 0.05). As a result of verifying statistical significance for measured CNR value, MFC, LFC, and Pat showed statistical significance (p < 0.05), while MTC and LTC did not show statistical significance (p > 0.05). As a result of a qualitative analysis, by comparing mean values for evaluated image items, 3D $T2^*$ weighted Image has indicated a slightly higher value. As for conformance verification between the two observers by using Kappa-value test, all evaluated items have indicated statistically significant results (p < 0.05). 3D $T2^*$ weighted technique holds a clinical value equal to or superior to 3D SPGR technique with respect to evaluating images, such as distinguishing knee joint cartilages, comparing nearby tissues contrast, and distinguishing lesions.

Intracranial Plasma Cell Granuloma

  • Kim, Dae-Jin;Choi, Yu-Seok;Song, Young-Jin;Kim, Ki-Uk
    • Journal of Korean Neurosurgical Society
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    • v.46 no.2
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    • pp.161-164
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    • 2009
  • Plasma cell granuloma is a tumor-like disease characterized by non-neoplastic polyclonal proliferation of plasma cells and other mononuclear cells. This disease occurs most frequently in the lung and upper respiratory tract, while the involvement of the central nervous system is very rare. A 44-year-old female patient presented with nausea and progressive visual disturbance. Brain magnetic resonance imaging (MRI) revealed the mass along the right tentorium with low signal intensity in the T2 weighted image (T2WI) and fluid-attenuated inversion recovery (FLAIR) sequence, and an isosignal intensity in T1 weighted image (T1WI), the latter of which was enhanced after administration of gadolinium-diethylenetriamine penta-acetic acid (Gd-DTPA). The thickest portion of the tentorium was partially excised via the combined suboccipital and infratentorial approach. The histopathological examination indicated a diagnosis of plasma cell granuloma. Postoperative steroid therapy was administered for remnant tumor control. Although a follow up MRI scan taken 20 months after the operation showed a slight decrease in tumor size, the lesion had extended to the falx and left frontal convexity along with parenchymal edema at 32 months after the operation and the clinical status was aggravated. The mass was removed from the left frontal convexity. Radiation therapy was given, together with steroid administration.

Cystic Hemangiopericytoma in the Third Ventricle

  • Sim, Jong-Eun;Jeong, Jin-Sook;Choi, Sun-Seob;Choi, Young-Min;Kim, Ki-Uk
    • Journal of Korean Neurosurgical Society
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    • v.40 no.6
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    • pp.467-470
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    • 2006
  • Primary intracranial hemangiopericytoma is rare and resemble meningioma on imaging study. It shows meningeal attachment, and is usually isointense with gray matter on T1-weighted MR image with heterogeneous enhancement and prominent vascular flow voids on T2-weighted image. Cystic type of hemangiopericytoma is very rare and only 3 cases have been reported in the literature which arised in the middle fossa, cerebellum, and occipital area. Ventricular hemangiopericytomas were reported in 9 cases, and all of them were solid type. Authors experienced a peculiar case of cystic hemangiopericytoma in the 3rd ventricle and report it with review of the literature.

Coexistence of Subcutaneous Dermoid Cyst and Lipomyelomeningocele

  • Kim, Young-Hoon;Jahng, Tae-Ahn;Chung, Chun-Kee
    • Journal of Korean Neurosurgical Society
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    • v.39 no.4
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    • pp.310-313
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    • 2006
  • Although lipomyelomeningocele and dermoid cyst are formed during a similar embryologic developmental stage of 'neural tube formation', they are caused by entirely different embryologic mechanisms. We encountered a case, which has not been previously reported, that had a lumbar subcutaneous dermoid cyst associated with lipomyelomeningocele. A 52-year-old man presented with a slowly growing lumbar mass of 3 years duration, which had been present since birth. Lumbosacral magnetic resonance imaging[MRI] showed lipomyelomeningocele at the L3, 4 and 5 levels and a subcutaneous cystic mass of high signal intensity on the T2 weighted image and iso or low signal intensity on the T1 weighted image. He underwent total resection of the lumbar subcutaneous mass. Intraoperative findings and histological examination were consistent with the preoperative diagnosis of a 'dermoid cyst'. We demonstrate that the formation of a dermoid cyst might coexist with lipomyelomeningocele during the embryologic developmental stage.

Correction of Receiver Gain using Noise′s Standard Deviation for Reconstruction of T$_1$/T$_2$ Maps (T$_1$/T$_2$ maps 의 재구성을 위해 잡음의 표준편차를 이용한 수신 증폭률 보정)

  • 김미나;김성은;신승애;정은기
    • Progress in Medical Physics
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    • v.10 no.3
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    • pp.125-131
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    • 1999
  • T$_1$/T$_2$ weighted images are being used to give the characteristic contrast among the various tissues and the norma;/abnormal tissues. Abnormalities in tissues, in general, accompany the biochemical changes and eventually structural ones in which results in the change in T$_1$ and T$_2$ relaxation times of water protons. It has been suggested that the mapping of T$_1$/T$_2$ values may serve as a possible tool for the quantitative evaluation of the degree of abnormality. On reconstructing T$_1$/T$_2$ maps(or any other MR parametric map), only corresponding variables are to be varied, such as TE for T$_2$, TI or TR for T$_1$ and b-factor for diffusion images. But often the receiver gain is taken for the optimal usage of A/D converter, so that the set of the image data has different receiver gain. It must be corrected before any attempt to reconstruct the maps. Here we developed method of correcting receiver gain variation effect, using the standard deviation of noise on individual image. The resultant T$_1$ and T$_2$ values were very comparable to the other reported values.

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Spontaneous Lumbar Epidural Hematoma Mimicking Lumbar Disc Herniation (요추 추간판 탈출증과 유사한 자발성 경막외 혈종)

  • Kyung, Dong Hyun;Moon, Byung Gwan;Kim, Joo Seung;Kang, Hee In;Lee, Seung Jin
    • Journal of Korean Neurosurgical Society
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    • v.29 no.5
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    • pp.623-627
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    • 2000
  • Objective : Spontaneous lumbar epidural hematoma is a rare entity, although the precipitating factors such as anticoagulation therapy frequently precede it. The authors report four cases of surgically confirmed spontaneous epidural hematoma mimicking lumbar disc herniation. Methods : Between 1995 and 1998, four patients with spontaneous lumbar epidural hematoma were diagnosed. The clinical findings which are identical to that of acute disc herniation are included in this study. The operative findings and radiological characteristics are also included. Results : The magnetic resonance(MR) image findings demonstrated epidural lesions of intermediate to low signal intensity equivalent to those of normal discs on $T_1$-weighted images, and epidural lesions of high signal intensity higher than these normal discs on a $T_2$-weighted image. The image findings also showed rim enhanced pattern of the gadolinium-enhanced $T_1$-weighted MR images. All of the hematomas was associated with a small concomitant disc herniation or underlying annular tear. Conclusion : The authors speculate that spontaneous lumbar epidural hematoma results from tearing of the fragile penetrating vein caused by underlying disc or annulus disruption between Batson' plexus and vertebral body.

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Usefulness of subtraction pelvic magnetic resonance imaging for detection of ovarian endometriosis

  • Lee, Hyun Jung
    • Yeungnam University Journal of Medicine
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    • v.37 no.2
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    • pp.90-97
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    • 2020
  • Background: To minimize damage to the ovarian reserve, it is necessary to evaluate the follicular density in the ovarian tissue surrounding endometriosis on preoperative imaging. The purpose of the present study was to evaluate the usefulness of subtraction pelvic magnetic resonance imaging (MRI) to detect ovarian reserve. Methods: A subtracted T1-weighted image (subT1WI) was obtained by subtracting unenhanced T1WI from contrast-enhanced T1WI (ceT1WI) with similar parameters in 22 patients with ovarian endometriosis. The signal-to-noise ratio (SNR) in ovarian endometriosis, which was classified into the high signal intensity and iso-to-low signal intensity groups on the T2-weighted image, was compared to that in normal ovarian tissue. To evaluate the effect of contrast enhancement, a standardization map was obtained by dividing subT1WI by ceT1WI. Results: On visual assessment of 22 patients with ovarian endometriosis, 16 patients showed a high signal intensity, and 6 patients showed an iso-to-low signal intensity on T1WI. Although SNR in endometriosis with a high signal intensity was higher than that with an iso-to-low signal intensity, there was no difference in SNR after the subtraction (13.72±77.55 vs. 63.03±43.90, p=0.126). The area of the affected ovary was smaller than that of the normal ovary (121.10±22.48 vs. 380.51±75.87 ㎟, p=0.002), but the mean number of pixels in the viable remaining tissue of the affected ovary was similar to that of the normal ovary (0.53±0.09 vs. 0.47±0.09, p=0.682). Conclusion: The subtraction technique used with pelvic MRI could reveal the extent of endometrial invasion of the normal ovarian tissue and viable remnant ovarian tissue.

Solitary Plasmacytoma of the Bone: Radiologic Findings (골단일 형질세포종 : 방사선학적 소견)

  • Yoon, Choon-Sik;Kim, Myung-Joon;Ahn, Chang-Soo;Suh, Jin-Suck;Shin, Kyoo-Ho
    • The Journal of the Korean bone and joint tumor society
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    • v.6 no.2
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    • pp.61-68
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    • 2000
  • Purpose : We examined the patients to evaluate the radiologic findings of solitary plasmacytoma of the bone. Materials and Methods : We retrospectively reviewed radiologic findings of 9 cases with solitary plasmacytoma of the bone (SPB) for recent 5 years, but 2 cases were not included this study due to an abnormal finding of bone marrow and another 2 cases were not included due to an abnormal manifestations of computed tomography (n=1) and MRI (n=1). Results : Among 5 cases, 4 cases had an osteolytic bone destruction and 1 case had an osteosclerotic bone destruction on the plain radiograph. Computed tomography and MRI showed more informations about trabeculated bone destruction and the soft-tissue extension of the lesion comparing to plain radiographs. The MRI finding of SPB in 4 cases showed a relatively high signal intensity on T1-weighted image and intermediate signal intensity on T2-weighted image, on which the signal intensity of the lesion is slightly higher than that of the muscle. One case had an extensive soft-tissue involvement and multiple necrosis, which presented iso to low signal intensity on T1-weighted image and high heterogeneous signal intensity on T2-weighted image. The Gadolinium-enhanced T1-weighted images of 5 cases showed diffusely strong enhancement of the lesion except on the necrosis areas. Conclusion : Computed tomography and MRI may present some characteristics of SPB and demonstrate another foci of plasma cell infiltrates, so these can be helpful for the diagnosis and treatment of SPB.

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Automatic Brain Segmentation for 3D Visualization and Analysis of MR Image Sets (MR영상의 3차원 가시화 및 분석을 위한 뇌영역의 자동 분할)

  • Kim, Tae-Woo
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.2
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    • pp.542-551
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    • 2000
  • In this paper, a novel technique is presented for automatic brain region segmentation in single channel MR image data sets for 3D visualization and analysis. The method detects brain contours in 2D and 3D processing of four steps. The first and the second make a head mask and an initial brain mask by automatic thresholding using a curve fitting technique. The stage 3 reconstructs 3D volume of the initial brain mask by cubic interpolation and generates an intermediate brain mask using morphological operation and labeling of connected components. In the final step, the brain mask is refined by automatic thresholding using curve fitting. This algorithm is useful for fully automatic brain region segmentation of T1-weighted, T2-weighted, PD-weighted, SPGR MRI data sets without considering slice direction and covering a whole volume of a brain. In the experiments, the algorithm was applied to 20 sets of MR images and showed over 0.97 in comparison with manual drawing in similarity index.

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3T MR Spin Echo T1 Weighted Image at Optimization of Flip Angle (3T MR 스핀에코 T1강조영상에서 적정의 숙임각)

  • Bae, Sung-Jin;Lim, Chung-Hwang
    • Journal of radiological science and technology
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    • v.32 no.2
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    • pp.177-182
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    • 2009
  • Purpose : This study presents the optimization of flip angle (FA) to obtain higher contrast to noise ratio (CNR) and lower specific absorption rate (SAR). Materials and Method : T1-weighted images of the cerebrum of brain were obtained from 50$^\circ$ to 130$^\circ$ FA with 10$^\circ$ interval. Signal to noise ratios (SNRs) were calculated for white matter (WM), gray matter (GM), and background noise. The proper FA was analyzed by T-test statistics and Kruskal-wallis analysis using R1 = 1- exp ($\frac{-TR}{T1}$) and Ernst angle cos $\theta$ = exp ($\frac{-TR}{T1}$). Results : The SNR of WM at 130$^\circ$ FA is approximately 1.6 times higher than the SNR of WM at 50$^\circ$. The SNR of GM at 130$^\circ$ FA is approximately 1.9 times higher than the SNR of GM at 50$^\circ$. Although the SNRs of WM and GM showed similar trends with the change of FA values, the slowdown point of decrease after linear fitting were different. While the SNR of WM started decreasing at 120$^\circ$ FA, the SNR of GM started decreasing at less than 110$^\circ$. The highest SNRs of WM and GM were obtained at 130$^\circ$ FA. The highest CNRs, however, were obtained at 80$^\circ$ FA. Conclusion : Although SNR increased with the change of FA values from 50$^\circ$ to 130$^\circ$ at 3T SE T1WI, CNR was higher at 80$^\circ$ FA than at the usually used 90$^\circ$ FA. In addition, the SAR was decreased by using smaller FA. The CNR can be increased by using this optimized FA at 3T MR SE T1WI.

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