• Biomolecules & Therapeutics
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• 제17권1호
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• pp.98-103
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• 2009

Superparamagnetic iron oxide nanoparticles (SPIOs)-embedded chitosan microspheres were developed for magnetic resonance (MR)-traceable embolotherapy. SPIOs-loaded chitosan microspheres were prepared by emulsion and cross-linking technique and 100-200 ${\mu}m$ sized spherical microsparticles were obtained. Loading efficacy and loading amount of SPIOs in microspheres were about 40% and 0.26-0.32%, respectively, when measured by inductively coupled plasma atomic emission spectroscopy. Within 30 days, about 60% of the incorporated SPIOs were released from low cross-linked microspheres, whereas only about 40% of SPIOs was released from highly cross-linked microspheres. Highly cross-linked microspheres were more efficient for lower degree of swelling leading to secure entrapment of SPIOs in matrix. Prepared novel embolic microspheres are expected to be practically applicable for traceable embolotherapy with high resolution and sensitivity through magnetic resonance imaging (MRI).

• 반도체디스플레이기술학회지
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• 제16권3호
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• pp.111-115
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• 2017

Terahertz waves are superior to conventional X-ray or Magnetic Resonance Tomography(MRI), and the amount of information that can be transmitted is as large as thousands of times that conventional X-ray or MRI. In addition, Terahertz waves have great performance in analyzing an object which have some layered structure. By using this advantage, we can extract the letters of a page by analyzing information such as absorption amount and reflection amount by irradiating a closed book with pulses of various frequencies within gap of a terahertz wave. However, in the image of each page using the Terahertz wave might be obtained various kinds of noise and the different character occlusion region. So, to extract letters from the terahertz image, we must take the noise and occlusion region away. We have been working to enhancement the image quality in various ways, and keep on studying de-noising processing for enhancement about the image quality and high resolution. Finally, we also keep on studying about OCR(Optical Character Recognition) technology, which based on pattern matching technique, to read letters.

• Investigative Magnetic Resonance Imaging
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• 제10권2호
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• pp.89-97
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• 2006

목적 : 자기공명영상 화질을 평가하는 팬텀으로서 코일 장착도구가 내장된 새로운 형태의 팬텀을 개발하였다. 대상 및 방법 : 자기공명영상 화질평가항목인 절편 두께 정확도, 공간 분해능, 대조도 분해능, 기하학적 정확도, 절편 위치 정확도, 영상강도 균일성, 고스트 신호 백분율, 신호대잡음비 등 총 8개의 사양을 가진 팬텀을 고안하였다. 팬텀의 코일 장착을 위한 장치가 팬텀 표면에 설치 되었다. 개발된 팬텀의 임상적용가능성을 알아보기 위하여 6개의 다른 종류의 자기공명영상기기를 사용하여 영상을 습득하였고 이들 화질이 평가되었다. 결과 : 사용된 모든 자기공명영상기기에서 영상평가에 문제가 없는 영상을 보여주었고 그들의 평가결과는 일부 평가항목에서 실측치와 비교하여 적절한 값 범위에 있음을 확인하였다. 코일장착도구를 사용하여 팬텀을 두부용 코일 안에 설치하는 데 문제가 없음을 확인하였다. 결론 : 본 논문에서 개발된 팬텀은 자기공명영상 화질을 평가하는 데 있어 그 임상적용 가능성이 있음을 보여주었다.

• Journal of Korean Neurosurgical Society
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• 제29권7호
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• pp.891-898
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• 2000

Objective : It is difficult to differentiate intramedullary spinal cord tumors preoperatively from non-neoplastic pathologies in patients presenting as non-compressive myelopathies in magnetic resonance imaging(MRI). In this report, the authors reviewed nonneoplastic intramedullary spinal cord lesions preoperatively diagnosed as tumors and discussed their clinical and radiological characteristics and usefulness of surgical intervention. Methods : From January, 1985 to January, 1999, authors experienced eight non-neoplastic pathologies mimicking intramedullary spinal cord tumors and analysed their medical records, radiological findings and histopathological specimens retrospectively. Results : There were five males and three females and the duration of symptoms were from two to 20 months(mean, 9.8 months). The location of lesions were four cervical, one cervicothoracic and three thoracic. All patients manifested sensory abnormality, seven motor weakness, and six bladder symptom. All cases had swollen spinal cords and increased signal intensities in spin-echo sequences. Six cases showed contrast enhancement : four cases were focal and two diffuse. Under the impression of intramedullary tumors, the patients were operated upon. Final diagnoses on the base of clinical and pathologic finding were : three subacute necrotizing myelopathies, two multiple scleroses, two myelopathy of unknown etiology. One case showed no gross abnormality in surgical field in spite of adequate exposure of the lesion, so biopsy was not performed. In that case, postoperative MRI revealed spontaneous resolution of the lesion. Conclusion : MRI is invaluable diagnostic tool in screening myelopathies. However, its high sensitivity and lack of specificity make difficulty in preoperative differential diagnosis of non-compressive myelopathies. Although no surgical morbidity occurred in our series, we sometimes failed to confirm definite diagnosis even with biopsy. In such a circumstance, long-term follow up is needed.

• 대한영상의학회지
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• 제82권5호
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• pp.1103-1123
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• 2021

자궁은 크게 자궁체부와 자궁경부로 나뉜다. 이 중 자궁내막과 자궁근층으로 이루어진 자궁체부에는 양성에서 악성 종양까지 다양한 질환이 발생한다. 비침습적인 일차적 평가로 초음파와 컴퓨터단층촬영이 있으나 비특이적인 영상 소견으로 감별이 어려운 경우가 있다. 반면 높은 해상도와 병리학적 특성 파악이 가능한 자기공명영상은 병변의 위치 확인뿐만 아니라 조직학적 특징, 그리고 악성 종양의 병기 설정에도 도움을 준다. 이 종설에서는 영상의학과 의사들이 알아야 할 자궁체부에서 볼 수 있는 다양한 양성과 악성 종양들의 특징적인 자기공명영상 소견들과 이들의 감별점에 대해 정리했다.

• Investigative Magnetic Resonance Imaging
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• 제5권2호
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• pp.138-148
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• 2001

목적 : 임상적용 가능시간 내에 세계 최초의 3T 능동차폐형 자석을 장착한 전신용 자기공명영상장비를 이용하여 고해상도의 자기공영영상을 획득하였다. 대상 및 방법: 128 MHz의 공명주파수를 갖는 RF코일을 사용하여 정상인으로부터 스핀에코와 고속 스핀에코 펄스 시퀀스를 적용한 두뇌, 무릎, 발 및 손목영상 등을 획득하였다. 전형적인 펄스시퀀스의 매개변수는 $512{\times}512$ matrix, 20 cm FOV, 3 mm 절편두께, 1 NEX를 사용하였다. 특히 T1 강조영상을 위하여 TR=500 ms, TE=10 혹은 17.4 ms을 사용하였으며, T2 강도영상을 위하여 TR=4000 ms, TE=108 ms을 사용하였다. 결과: 3T의 신호대잡음비는 기존 병원에 설치된 1.57에 비하여 2.7배 정도 향상되었다. 3T자기공명영상은 매우 미세한 혈관 구조물을 표출하는데 도움을 주며, 또한 백질과 회질의 상당한 대조도를 제공하여 주었다. 결론: 본 연구결과에서 37로부터 얻은 자기공명영상은 기존 1.57 영상에서 얻은 영상에 비하여 더 높은 해상도와 민감도를 제공하여 주었다 3T 고자장 자기공명영상에 나타난 증가된 신호대잡음비는 생체 조직단위의 영상을 획득하는데 유용하였다. 이러한 고해상도의 자기공명영상은 비침습적인 방법으로서 미세조직의 이상유무를 진단하는데 있어서 향후 더욱 임상에 도움을 주리라 예상한다.

• Korean Journal of Radiology
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• 제21권12호
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• pp.1334-1344
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• 2020

Objective: Compressed sensing (CS) has gained wide interest since it accelerates MRI acquisition. We aimed to compare the 3D post-contrast T1-weighted volumetric isotropic turbo spin echo acquisition (VISTA) with CS (VISTA-CS) and without CS (VISTA-nonCS) in intracranial vessel wall MRIs (VW-MRI). Materials and Methods: From April 2017 to July 2018, 72 patients who underwent VW-MRI, including both VISTA-CS and VISTA-nonCS, were retrospectively enrolled. Wall and lumen volumes, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) were measured from normal and lesion sites. Two neuroradiologists independently evaluated overall image quality and degree of normal and lesion wall delineation with a four-point scale (scores ≥ 3 defined as acceptable). Results: Scan coverage was increased in VISTA-CS to cover both anterior and posterior circulations with a slightly shorter scan time compared to VISTA-nonCS (approximately 7 minutes vs. 8 minutes). Wall and lumen volumes were not significantly different with VISTA-CS or VISTA-nonCS (interclass correlation coefficient = 0.964-0.997). SNR was or trended towards significantly higher values in VISTA-CS than in VISTA-nonCS. At normal sites, CNR was not significantly different between two sequences (p = 0.907), whereas VISTA-CS provided lower CNR in lesion sites compared with VISTA-nonCS (p = 0.003). Subjective wall delineation was superior with VISTA-nonCS than with VISTA-CS (p = 0.019), although overall image quality did not differ (p = 0.297). The proportions of images with acceptable quality were not significantly different between VISTA-CS (83.3-97.8%) and VISTA-nonCS (75-100%). Conclusion: CS may be useful for intracranial VW-MRI as it allows for larger scan coverage with slightly shorter scan time without compromising image quality.

• 한국초전도ㆍ저온공학회논문지
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• 제2권1호
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• pp.31-34
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• 2000

this paper deals with the initial magnetic field decay for a large scale superconducting magnet e.g. NMR/MRI magnet. The high resolution image can not be obained during the periods of the initial field decay. It is known that all superconducting materials have the property of diamagnetism. This diamagnetism is usually explained with the concept of screening current. We assumed that the existence of the screening currebt. we assumed that the existence of the screening current makes the current distribution in the superconducting wire non-uniform. And the initial magnetic field decay is caused steady current state in the view of its pattern. The initial magnetic field decay is caused by the change of the current distribution between the energizing state and persistent current mode. in this paper the theoretical analysis for the current distributions has been introduced for each state. The experiments have been carried out to verify transport currents in order to veperiments, it small at the higher transport current.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 1999년도 Japanese Journal of Medical Physics
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• pp.423-424
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• 1999

• Journal of the Optical Society of Korea
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• 제10권1호
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• pp.42-47
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• 2006

M-mode imaging of the in vivo murine myocardium using optical coherence tomography (OCT) is described. Application of conventional techniques (e.g. MRI, Ultrasound imaging) for imaging the murine myocardium is problematic because the wall thickness is less than 1.5 mm (20 g mouse), and the heart rate can be as high as six hundred beats per minute. To acquire a real-time image of the murine myocardium, OCT can provide sufficient spatial resolution ($10{\mu}m$) and imaging speed (1000 A-scans/s). Strong light scattering by blood in the heart causes significant light attenuation, which makes delineation of the endocardium-chamber boundary problematic. To measure the thickness change of the myocardium during one heart beat cycle, a myocardium edge detection algorithm is developed and demonstrated.