• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.457-460
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• 2002

The image quality of three-dimensional (3D) images has been widely investigated by the qualitative analysis method. A need remains for an objective and quantitative method to assess the image quality of 3D volume-rendered images. The purpose of this study was to evaluate the quantitative accuracy of distance measurements on 3D volume-rendered images of a dry human skull by using multi-detector computed tomography (MDCT). A radiologist measured five times the twenty-one direct measurement line items composed among twelve reference points on the skull surface with a digital vernier caliper. The water filled skull specimen was scanned with a MDCT according to the section thicknesses of 1.25, 2.50, 3.75, and 5.00 mm for helical (high quality; pitch 3:1) scan mode. MDCT data were reconstructed with its acquisition section thickness and with 1.25 mm section thickness for all scans. An observer also measured seven times the corresponding items on 3D volume-rendered images with measuring tools provided by volumetric analysis software. The quantitative accuracy of distance measurements on the 3D volume-rendered images was statistically evaluated (p-value < 0.05) by comparatively analyzing these measurements with the direct distance measurements. The accuracy of distance measurements on the 3D volume-rendered MDCT images acquired with 1.25, 2.50, 3,75 and 5.00 mm section thickness and reconstructed with its section thickness were 48%, 33%, 23%, and 14%, respectively. Meanwhile, there were insignificant statistical differences in accuracy of distance measurements among 3D volume-rendered images reconstructed with 1.25 mm section thickness for the each acquisition section thickness. MDCT images acquired with thick section thickness and reconstructed with thin section thickness in helical scan mode should be effectively used in medical planning of 3D volume-rendered images. The quantitative analysis of distance measurement may be a useful tool for evaluating the quantitative accuracy and the defining optimal parameters of 3D volume-rendered CT images.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.322-323
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• 2002

Partial volume averaging effect of PET data influences on the accuracy of quantitative measurements of regional brain metabolism because spatial resolution of PET is limited. The purpose of this study was to evaluate the accuracy of partial volume correction carried out on $^{18}$ F-PET images using Hoffman brain phantom. $^{18}$ F-PET Hoffman phantom images were co-registered to MR slices of the same phantom. All the MR slices of the phantom were then segmented to be binary images. Each of these binary images was convolved in 2 dimensions with the spatial resolution of the PET. The original PET images were then divided by the smoothed binary images in slice-by-slice, voxel-by-voxel basis resulting in larger PET image volume in size. This enlarged partial volume corrected PET image volume was multiplied by original binary image volume to exclude extracortical region. The evaluation of partial volume corrected PET image volume was performed by region of interests (ROI) analysis applying ROIs, which were drawn on cortical regions of the original MR image slices, to corrected and original PET image volume. From the ROI analysis, range of regional mean values increases of partial volume corrected PET images was 4 to 14%, and average increase for all the ROIs was about 10% in this phantom study. Hoffman brain phantom study was useful for the objective evaluation of the partial volume correction method. This MR-based correction method would be applicable to patients in the. quantitative analysis of FDG-PET studies.

• Imaging Science in Dentistry
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• 제53권1호
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• pp.69-75
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• 2023

Purpose: Maxillofacial trauma predominantly affects young adults between 20 and 40 years of age. Although radioprotection is a legal requirement, the significant potential of dose reduction in computed tomography (CT) is still underused in the clinical routine. The objective of this study was to evaluate whether maxillofacial fractures can be reliably detected and classified using ultra-low-dose CT. Materials and Methods: CT images of 123 clinical cases with maxillofacial fractures were classified by two readers using the AOCOIAC software and compared with the corresponding results from post-treatment images. In group 1, consisting of 97 patients with isolated facial trauma, pre-treatment CT images at different dose levels (volumetric computed tomography dose index: ultra-low dose, 2.6 mGy; low dose, <10 mGy; and regular dose, <20 mGy) were compared with post-treatment cone-beam computed tomography (CBCT). In group 2, consisting of 31 patients with complex midface fractures, pre-treatment shock room CT images were compared with post-treatment CT at different dose levels or CBCT. All images were presented in random order and classified by 2 readers blinded to the clinical results. All cases with an unequal classification were re-evaluated. Results: In both groups, ultra-low-dose CT had no clinically relevant effect on fracture classification. Fourteen cases in group 2 showed minor differences in the classification code, which were no longer obvious after comparing the images directly to each other. Conclusion: Ultra-low-dose CT images allowed the correct diagnosis and classification of maxillofacial fractures. These results might lead to a substantial reconsideration of current reference dose levels.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제5권2호
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• pp.69-78
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• 2016

허혈성 뇌졸중은 뇌혈관의 혈전이나 색전에 의해 뇌 혈류가 감소하게 되어 뇌 조직이 기능을 못하는 질환으로, 질환의 특성상 뇌혈관의 폐색 여부를 확인하는 것이 중요하기 때문에 질환의 진단에 있어서 의료 영상이 필수적으로 활용된다. 그 중에서도 뇌 자기공명영상은 뇌의 구조적인 정보들을 얻을 수 있어 질환을 진단하는데 그 지표로 널리 활용되고 있다. 하지만 허혈성 뇌졸중과 같은 응급 질환의 경우 빠른 진단과 처치에 도움이 될 수 있는 지능적인 시스템이 요구됨에 비해, 기존의 의료 영상 저장 시스템으로는 신속하고 직관적인 영상 정보 제공이 어렵다. 즉, 기존의 시스템은 피상적인 메타 데이터를 이용하여 의료 영상을 관리하고 있어 의료 영상에 내재된 주요 의미적 정보를 고려하지 못하고 있다. 따라서 본 논문에서는 뇌 자기공명영상이 내포하고 있는 주요 의미적인 정보인 뇌의 해부학적 구조와 같은 영상 정보를 제공할 수 있도록 하는 템플릿 중심의 영상 매핑 기법을 제안하고자 한다. 제안하는 기법은 방대한 양의 영상을 대표할 수 있는 대표 영상(템플릿)을 선정하여 의미적 특징과 대표 영상(템플릿) 사이의 대응성을 정립하고, 전문가(의사)에 의해서만 분석될 수 있는 영상 사이의 의미적 연관성을 표면화 시켜 의미 기반의 영상 관리를 가능케 한다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 Ⅳ
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• pp.2395-2398
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• 2003

This paper focuses on lossless medical image compression methods for medical images that operate on two-dimensional(2D) reversible integer wavelet transform. We offer an application of the Set Partitioning in Hierarchical Trees(SPIHT) algorithm [1][3][9] to medical images, using a 2D wavelet decomposition and a 2D spatial dependence tree. The wavelet decomposition is accomplished with integer wavelet filters implemented with the lifting method, where careful scaling and truncations keep the integer precision small and the transform unitary. We have tested our encoder on medical images using different integer filters. Results show that our algorithm with certain filters performs as well and sometimes better in lossless coding than previous coding systems using 2D integer wavelet transforms on medical images.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제9권3호
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• pp.172-177
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• 2009

In this paper, a new morphology-based homomorphic filtering technique is presented to enhance features in medical images. The homomorphic filtering is performed based on the morphological sub-bands, in which an image is morphologically decomposed. An evolutionary design is carried to find an optimal gain and structuring element of each sub-band. As a search algorithm, Differential Evolution scheme is utilized. Simulations show that the proposed filter improves the contrast of the interest feature in medical images.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.104-107
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• 1997

A medical teleconferencing and medical image transmision system has been developed for diagnosis of the medical images between the medical doctors who are far away. The medical teleconferencing system transmits the voice and image of the doctors using the video and audio capture boards. The medical image transmission system software uses the medical image standard DICOM 3.0 for the future expansibility and the open system interconectivity. The medical images usually use CR images.

• 한국컴퓨터정보학회논문지
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• 제14권12호
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• pp.191-199
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• 2009

의료영상에 대한 영상정보와 진단정보를 공유하는 환경으로 사용되는 의료영상 시스템은 효과적인 진단 보조 도구로 활용된다. 대규모 의료기관과 협력기관들은 통합 의료정보 시스템이 구축되어 영상정보와 진단정보를 공유할 수 있다. 그러나 통합 의료정보 시스템은 단순히 정보의 저장과 전송만을 제공한다. 이러한 문제점을 해결하고 진단 활동의 효율성을 높이기 위해서는 의료영상 분석 시스템이 필요하다. 본 논문에서 제안한 관계기법은 속성 생성을 위해 의료영상을 분석하고, 본 기법 하에 의료영상은 여러 개의 객체로 분할되며, 의료영상 속성들은 분할된 영상에서 추출된다. 추출된 속성들은 의료영상 분석을 위해 관계기법에 적용된다. 몇 가지 실험 결과를 통해 제안 기법의 효과를 확인하였다.

• Journal of the Optical Society of Korea
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• 제15권3호
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• pp.300-304
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• 2011

Optical microscopes are widely used for medical imaging these days, but biopsy is a lengthy process that causes many problems during the ex-vivo imaging procedure. The endo-microscope has been studied to increase accessibility to the human body and to get in-vivo images to use for medical diagnosis. This research proposes a multi-modal confocal endo-microscope for bio-medical imaging. We introduce the design process for a small endoscopic probe and a coupling mechanism for the probe to make the multi-modal confocal endo-microscope. The endoscopic probe was designed to decrease chromatic and spherical aberrations, which deteriorate the images obtained with the conventional GRIN lens. Fluorescence and reflectance images of various samples were obtained with the proposed endo-microscope. We evaluated the performance of the proposed endo-microscope by analyzing the acquired images, and demonstrate the possibilities of in-vivo medical imaging for early diagnosis.

• 한국반도체및디스플레이장비학회:학술대회논문집
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• 한국반도체및디스플레이장비학회 2004년도 춘계학술대회 발표 논문집
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• pp.217-222
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• 2004

This paper focuses on lossy medical image compression methods for medical images that operate on two-dimensional(2D) integer wavelet transform. We offer an application of the Set Partitioning in Hierarchical Trees(SPIHT) algorithm to medical images, using a 2D wavelet decomposition and a 2D spatial dependence tree. The wavelet decomposition is accomplished with integer wavelet filters implemented with the lifting method, where careful scaling and truncations keep the integer precision small and the transform unitary. We have tested our encoder on medical images using different integer filters. Results show that our algorithm with certain filters performs as well and is sometimes better lossy coding using 2D integer wavelet transforms on medical images.