• Investigative Magnetic Resonance Imaging
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• 제13권2호
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• pp.190-194
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• 2009

전신성 림프관종증은 림프관의 드문 선천성 기형이다. CT와 MR 영상은 림프관종 진단에 이용되고 있고 액체로 가득찬 다낭성의 큰 종괴로 보이고 이러한 영상 소견으로 림프관종과 다양한 혈관 질환을 감별하는 데 도움이 된다. 저자는 전신성 림프관종증 환자의 CT, MR영상과 방사선 동위원소 영상소견을 보고한다. STIR 영상 연쇄 기법을 이용한 전신 3.0-T MR 영상은 고해상도 다른 영상 장비에서 진단하지 못한 부가적인 병변을 발견할 수 있었다. 저자는 전신 3.0T MR 영상이 전신성 림프관종증 환자의 침범정도 평가나 추적관찰에 유용한 진단 장비라고 생각한다.

• Tuberculosis and Respiratory Diseases
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• 제40권4호
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• pp.345-352
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• 1993

The role of magnetic resonance(MR) imaging in the evaluation of thoracic disease has been limited Nontheless, MR has inherent properties of better contrast resolution than CT allowing tissue-specific diagnosis. MR has capability of direct imaging in sagittal, coronal, and oblique planes which provide better anatomic information than axial images of CT such as lesions in the pulmonary apex, aorticopulmonary window, peridiaphragmatic region, and subcarinal region. MR is sensitive to blood flow making it an ideal imaging modality for the evaluation of cardiovascular system of the thorax without the need for intravenous contrast media. Technical developments and better control of motion artifacts have resulted in improved image quality, and clinical applications of MR imaging in thoracic diseases have been expanded. Although MR imaging is considered as a problem-solving tool in patients with equivocal CT findings, MR should be used as the primary imaging modality in the following situations: 1) Evaluation of the cardiovascular abnormalities of the thorax 2) Evaluation of the superior sulcus tumors 3) Evaluation of the chest wall invasion or mediastinal invasion by tumor 4) Evaluation of the posterior mediastinal mass, especially neurogenic tumor 5) Differentiation of fibrosis and residual or recurrent tumor, especially in lymphoma 6) Evaluation of brachial plexopathy With technical developments and fast scan capabilities, clinical indications for MR imaging in thorax will increase in the area of pulmonary parenchymal and pulmonary vascular imaging.

• Journal of Korean Neurosurgical Society
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• 제43권6호
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• pp.275-280
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• 2008

Objective : In order to assess the incidence of thromboembolic events and their clinical presentations, the present study prospectively examined routine brain magnetic resonance images (MRI) taken within 48 hours after a coil embolization of cerebral aneurysms. Methods : From January 2006 to January 2008, 163 cases of coil embolization of cerebral aneurysm were performed along with routine brain MRI, including diffusion-weighted magnetic resonance (DW-MR) imaging, within 48 hours after the embolization of the aneurysm to detect the silent thromboembolic events regardless of any neurological changes. If any neurological changes were observed, an immediate brain MRI follow-up was performed. High-signal-intensity lesions in the DW-MR images were considered as acute thromboembolic events and the number and locations of the lesions were also recorded. Results : Among the 163 coil embolization cases, 98(60.1%) showed high-signal intensities in the DW-MR imaging follow-up, 66 cases (67.0%) involved the eloquent area and only 6cases (6.0%) showed focal neurological symptoms correlated to the DW-MR findings. The incidence of DW-MR lesions was higher in older patients (${\geq}60$ yrs) when compared to younger patients (<60 yrs) (p=0.002, odd's ratio=1.043). The older patients also showed a higher incidence of abnormal DW-MR signals in aneurysm-unrelated lesions (p=0.0003, odd's ratio=5.078). Conclusion : The incidence of symptomatic thromboembolic attacks after coil embolization of the cerebral aneurysm was found to be lower than that reported in previous studies. While DW-MR imaging revealed a higher number of thromboembolic events, most of these were clinically silent and transient and showed favorable clinical outcomes. However, the incidence of DW-MR abnormalities was higher in older patients, along with unpredictable thromboembolic events on DW-MR images. Thus, in order to provide adequate and timely treatment and to minimize neurological sequelae, a routine DW-MR follow-up after coil embolization of cerebral aneurysms might be helpful, especially in older patients.

• Investigative Magnetic Resonance Imaging
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• 제2권1호
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• pp.1-13
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• 1998

MR 영상을 획득하기 위해서 사용하고 있는 가장 기본적인 펄스파형(pulse sequense)은 스핀반향(spin echo)과 경사자계반향(gradient echo)이며, 최근 다방면으로 응용되고 있는 고속영상기법들은 이 두가지 펄스파형을 기보능로 하고 있다. 펄스파형의 종류와 펄스파형의 변수(TR, TE TI등의 펄스 상이의 시간 간격 및 flip angle 등)에 따라서 MR영상의 특징(대조도, SNR, artifact 등)이 달라지므로 임상응용시에는 목적에 따라 적절한 펄스파혀의 선택과 함께 변수값을 결정해야 한다. 이를 위하여 펄스파형에 관한 기본적인 지식과 함게 간단한 임상응용에 관하여 기술하고자 한다.

• Nuclear Engineering and Technology
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• 제55권1호
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• pp.222-228
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• 2023

This study aimed to analyze the applicability of the improved median filter in positron emission tomography (PET)/magnetic resonance (MR) fusion images based on parallel imaging using generalized autocalibrating partially parallel acquisition (GRAPPA). In this study, a PET/MR fusion imaging system based on a 3.0T magnetic field and ¹⁸F radioisotope were used. An improved median filter that can set a mask of the median value more efficiently than before was modeled and applied to the acquired image. As quantitative evaluation parameters of the noise level, the contrast to noise ratio (CNR) and coefficient of variation (COV) were calculated. Additionally, no-reference-based evaluation parameters were used to analyze the overall image quality. We confirmed that the CNR and COV values of the PET/MR fusion images to which the improved median filter was applied improved by approximately 3.32 and 2.19 times on average, respectively, compared to the noisy image. In addition, the no-reference-based evaluation results showed a similar trend for the noise-level results. In conclusion, we demonstrated that it can be supplemented by using an improved median filter, which suggests the problem of image quality degradation of PET/MR fusion images that shortens scan time using GRAPPA.

• Investigative Magnetic Resonance Imaging
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• 제3권2호
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• pp.113-124
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• 1999

종래의 영상진단 방법은 골수의 이상을 검사하는데 상당한 제한점이 있는 상황에서 MR 영상은 골수를 칩습한 병변을 직접 묘출할 있는 우선적인 영상진단법으로 그 이용이 점차 증대되고 이다. 비록 골수 천자나 생검에 비해 조직학적 진단의 특이성은 떨어지나 환자의 임상증세와 혈액상을 연관지어 MR 영상 소견을 판독하면 골수의 병변을 진단하고 그 치료에 관한 반응을 해석하는데 유용한 정보를 줄 수 있으리라 기대된다.

• 한국통신학회논문지
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• 제22권11호
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• pp.2425-2431
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• 1997

자기 공명 영상의 사용이 빈번해 짐에 따라 환자의 해부학적인 정확한 정보와 이를 빠르고 효과적으로 진단하는데 유용한 자동 영상 세그멘테이션 방법이 요구되고 있다. 본 논문에서는 오류 역전파 알고리즘으로 학습한 신경망을 이용하여 뇌의 자기 공명 영상을 자동적으로 세그멘테이션하는 방법을 제안한다. 특정 환자의 자기 공명 영상을 분할하여 학습시킨 신경망은 다른 환자의 자기 공명 영상도 자동적으로 세그멘테이션하여 뇌의 윤곽을 뚜렷하게 나타내었다.

• Investigative Magnetic Resonance Imaging
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• 제11권1호
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• pp.54-57
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• 2007

국소성 소결절성 활막염은 무릎관절에 발생하는 드문 양성종양으로, 색소 융모결절성 활막염과 감별이 필요하다. 저자들은 자기공명영상에서 경 (pedicle)을 가지며 특징적인 MR 영상소견을 보이고 병리조직학적으로 확진된, 무릎에서 발생한 국소성 소결절성 활막염 1예를 보고한다.

• Investigative Magnetic Resonance Imaging
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• 제22권3호
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• pp.182-186
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• 2018

Dynamic enhanced magnetic resonance lymphangiography can be used to provide anatomic and dynamic information for various lymphatic diseases, including thoracic duct injury, and can also help to guide the thoracic duct embolization procedure. We present a case of postoperative chylothorax demonstrated by dynamic enhanced MR lymphangiography. In this case, the chyle leakage site and location of cisterna chyli were clearly visualized by dynamic enhanced MR lymphangiography, thus allowing for management with thoracic duct embolization.

• Investigative Magnetic Resonance Imaging
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• 제25권4호
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• pp.300-312
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• 2021

Compressed sensing (CS) has been investigated in magnetic resonance (MR) parametric mapping to reduce scan time. However, the relatively long reconstruction time restricts its widespread applications in the clinic. Recently, deep learning-based methods have shown great potential in accelerating reconstruction time and improving imaging quality in fast MR imaging, although their adaptation to parametric mapping is still in an early stage. In this paper, we proposed a novel deep learning-based framework DEMO for fast and robust MR parametric mapping. Different from current deep learning-based methods, DEMO trains the network in an unsupervised way, which is more practical given that it is difficult to acquire large fully sampled training data of parametric-weighted images. Specifically, a CS-based loss function is used in DEMO to avoid the necessity of using fully sampled k-space data as the label, thus making it an unsupervised learning approach. DEMO reconstructs parametric weighted images and generates a parametric map simultaneously by unrolling an interaction approach in conventional fast MR parametric mapping, which enables multi-tasking learning. Experimental results showed promising performance of the proposed DEMO framework in quantitative MR T1ρ mapping.