Contructice Interference in Steady State(CISS)법을 이용한 내이 및 주변 구조물의 3DFT MRI

정은철 대한영상의학회 1997 대한영상의학회지 Vol.36 No.3

복합수지운동에서 소뇌의 양측성 기여에 관한 기능적 자기공명영상 연구

정은철 대한영상의학회 1999 대한영상의학회지 Vol.40 No.1

Purpose : To demonstrate activation signals within the cerebellar cortex and to determine the side of the cerebellar cortex eliciting activation signals in response to complex motor tasks, as seen on EPI fMRI Materials and Methods : Seven right-handed subjects (M : F = 3 : 4 ; mean age, 30.3 years) underwent repetitive finger apposition with the dominant right hand. Using a 1.5 T MRI scanner, EPI fMR images were obtained. MR parameters used for EPI fMRI were TR/TE/Flip angle : 0.96 msec/64 msec/90$^{\circ}$, FOV 22cm, 128 $\times$ 128 matrix, 10 slices, 10 mm thickness while those for SE T1 weighted localized images were TR/TE : 450/16, FOV 23cm, 256 $\times$ 256 matrix. The paradigm was three sets of alternate resting and moving fingers for six cycles, resulting in times of 360 seconds (10 slices $\times$ 15 EPI $\times$ 6 cycles = 900 images). Image processing involoved the use of a 200mHz Dual Pentium PC with homemade software. T-testing (p < 0.005 ~ p < 0.0005) and time series analysis were performed, and to verify the locations of activated regions, resulting images were analyzed in a color-coded overlay to reference T1-weighted spin echo coronal images. percentage change in signal intensity (PCSI) was calculated from the processed data. Results : All normal subjects showed significant activation signals in both the contralateral (left) primary motor cortex (PCSI = 3.12% $\pm$ 0.96) and ipsilateral (right) cerebellar cortex (PCSI = 3.09%$\pm$ 1.14). Signal activation was detected in the contralateral supplemental motor area (2.91% $\pm$ 0.82), and motor activation in the anterior upper half of the contralateral cerebellum (PCSI = 2.50% $\pm$ 0.69). The difference in activation signals between both sides of the cerebellar cortex was not statistically significant. All data were matched with time-series analysis. Conclusion : Bilateral cerebellar activation is associated with unilateral complex finger movements, as seen on fMRI. This result maysupport the recent neurological observation that the cerebellum may exert bilateral effects on motor performance.

자기공명 신경영상술

鄭恩哲 대한의학협회 1995 대한의학협회지 Vol.38 No.10

펄스 전원 및 도금 두께가 경질 크롬 도금의 마이크로 크랙 발생에 미치는 영향

정은철,손경식,김용환,정원섭 한국표면공학회 2016 한국표면공학회 학술발표회 초록집 Vol.2016 No.11

肺腫塊의 經皮的 細針吸引生檢

鄭恩哲 梨花女子大學校 醫科大學 醫科學硏究所 1988 EMJ (Ewha medical journal) Vol.11 No.3

Percutaneous fine needle aspiration biopsy of lung masses is a simple and the most frequently used interventional procedure in radiologic department. Its use is progressively increased, relating to the improvemt of fluoroscopy and types of aspiration needle, and the advances in cyto-pathology. Over a period of recent 2 years, 21 cases of lung mass underwent percutaneous aspiration biopsy were analysed. 14 cases were proven as malignancy. 3 cases were benign lesions. Open lung biopsy and operation permit the exact pathology of the remaining 4 cases as malignancy. The overall diagnostic accuracy was 81%(17/21). Author recommended that the percutaneous fine needle aspiration biopsy must be inital procedure in diagnostic work-up of pulmonary masses.

MDS-Spiral Coil을 이용한 뇌 동맥류의 경혈관적 치료

정은철,최혜영,서대철,한문희 梨花女子大學校 醫科大學 醫科學硏究所 1995 EMJ (Ewha medical journal) Vol.18 No.4

수술적 치료가 적용되지 않았거나 수술적 접근이 어려웠던 2례의 동맥류환자에서 MDS coil을 이용하여 경헐관적 색전을 시행하였다. 후하소동맥의 동맥류의 경우는 4×80mm coil 한개를 색전한 후 후하소뇌동맥의 혈류가 일시적으로 감소하였으나 추적검사상 이상소견없이 완전한 색전을 보였다. 후교통동맥류의 예에서는 5×80mm coil세개를 성공적으로 삽입하고 3×8mm coil을 추가로 삽입하였을 때 coil의 일부가 동맥류의 경부에서 내경동맥으로 빠져 나왔다. Curved microsnare catheter를 이용하여 일부를 제거하고 일부는 동맥류와 내경동맥에 걸쳐있었다. 색전직후의 동맥조영검사상 동맥류는 성공적으로 색전되었으며 동맥조영검사상 내경동백을 폐색하지 않으므로 시술을 중지하였다. 뇌의 동맥류환자에서 수술이 불가능하거나 수술적 접근이 어려운 경우, 수술후 동맥류가 재발한 경우 또는 파열되지 않은 동맥류 등에서 MDS coil을 이용한 경혈관적색전술은 시술을 대치할 수 있는 유용한 치료법이다. 0bjectives : To report e experience of performing embolization procedure of aneurysms with mechanical detachable coils(MDC). Methods : Two patients underwent embolization of eneurysms with mechanical detachable coils. One patient who had an aneurysm in the left posterior inferior cereberllar artery(PICA) underwent the embolization procedure with one spiral coil(4mm×80mm) and another patient who had an aneurysm in the left posterior(P-comm.) communicating artery aneurysm underwent the embolization procedure with four spiral coils(three 5mm×8mm and one 3mm×80mm). Results : Immediately after coil placement in the PICA the flow of contrast in the PICA reduced significantly. It may resulted from compression of the origin of PICA by the coil-packed aneurysm. The posttreatment course was not uneventful In case of P-comm. aneursym, the last coil(3mm×80mm) which embolized in the aneurysm, escaped from the aneurysm into the left internal carotid artery. Thej retrieval of the coil in the internal carotid artery with 3F microretrieval cathter was sucesfully performed. Conclusion : This preliminary experience suggests that the embolization procedure with mechanical detachable coils is a usful modality of treatment of cerebral aneurysm in case ofinoperable cases.

Tuberous Sclerosis의 전산화단층촬영 소견

정은철 대한영상의학회 1988 대한영상의학회지 Vol.24 No.6

Computed tomgraphy has been established as a useful imaging method in the diagnosis of tuberous sclerosis. By demonstrating the characteristic intracranial lesion it allows confirmation of the diagnosis and provides a noninvasive means of evaluating the patient with seizure and mental retardation. Authors analysed CT findings in 20 cases of tuberous sclerosis since March 1985 through August 1988. the results were as follows: 1) There are 14 men and 6 women with the age ragng from 6 months to 45 years. 2) Ventricular calcified tubers are noted at the frontal horn (16/20 80%) body (13/20, 65%) atrium (9/20, 45%) of the lateral ventricles 1 cases shows the hamartoma near the foramen of Monro. 3)In the cortical region 1 case of high density tuber and 2 cases of focal atrophy are noted. 4) In the white mater 3 cases of amorphous calcifications and 1 cases of demyelinating hypodensity are seen,

디지털 트윈에 기반한 Texture Mapping 최적화 연구

정은철,배재훈,이병도,배윤경,김준택 국제차세대융합기술학회 2024 차세대융합기술학회논문지 Vol.8 No.1

제조업을 포함한 다양한 산업 분야에서 디지털 트윈을 활용하여 사업적인 운용 성능을 극대화하고 있다. 그러나 건축 분야의 디지털 트윈은 표현하고자 하는 공간의 범위가 매우 넓기 때문에 필요한 데이터 양도 증가하게 되어 디지털 트윈 구현에 어려움이 있지만, 이를 최적화하는 방식을 통해 그 효과를 높이고 있다. 이에 본 연구는 디지털 트윈 기술을 사용하여 실제의 건물을 스캔하고 이로부터 생성된 데이터의 Texture mapping 오차를최적화하는 방법을 제안한다. 이를 통해 기존의 가상공간과는 다른 메타버스 플랫폼의 기반구축과 그 특징을 알아보고자 한다. Leica RTC360, 3D Scanner, Metrix Camera, Drone으로 스캔한 실제의 섬과 건물 내부, 외부의XR 데이터를 디지털 트윈과 접목해 생산한 후, LoD(Level of Detail)를 적용한 최적화 과정을 거쳐 시각화하였다. 결과적으로 최적화된 디지털 트윈 Mesh와 Texture Mapping을 활용해 더욱 생동감 있는 메타 아일랜드 플랫폼을 구축할 수 있으며, 이는 가상공간 속에서 콘텐츠의 다양성을 높이는 기회 요소로 작용할 것이다. 이는 새로운 사용자층의 형성과 그에 따른 사용자 간의 상호작용을 촉진하여 공동체적 유대감 형성에 효과를 낼 것이다. Digital twins are used to maximize business operational performance in various industries, including manufacturing. However, since the digital twin in the architecture field has a very wide range of spaces to be expressed, the amount of data required increases, making it difficult to implement the digital twin, but it is increasing its effectiveness through optimization. Therefore, This study proposes a method of scanning real buildings using digital twins and optimizing the texture mapping error of the generated data, and through this, a meta bus platform base different from the existing virtual space is established and its characteristics are investigated. Accordingly, the actual island, inside, and outside XR data scanned with Trimble TX8, 3D Scanner, Metrix Camera, and Drone were produced by combining them with digital twins, and then visualized by applying LoD (Level of Detail) to optimize them. As a result, a more lively meta-island platform can be built by optimizing the texture mapping process using digital twins, and as an opportunity factor to increase the diversity of content in virtual space, it will contribute to the formation of a new user layer and the resulting interaction between users.

Digital Radiography를 이용한 원발성 폐섬유화증의 검출능에 대한 ROC 연구

정은철 대한영상의학회 1991 대한영상의학회지 Vol.27 No.2

One potential advantage of the digital radiography system is its ability to enhance image quality by various types of processing. Digital unsharp masking is one of the simplest and most useful forms of enhancing processes. The efficacy of unsharp masking in radiological diagnosis has not been investigated thoroughly. To evaluate the effects of unsharp masking in film-digital chest images, 3 observers were shown 150 test radiographs. These test radiographs consisted of 50 unprocessed images(25 normals and 25 patients with idiopathic pulmonary fibrosis with honey combing) adn their 100 processed images by using 450 and 15-sized masks respectively. An ROC analysis of these data suggests that unsharp masking is more effective in detecting idiopathic pulmonary fibrosis than unprocessed image(P<0.05), and so it may improve diagnostic accurary for interstitial fibrosis. In addition, the smaller mask size(15) is more effective than the larger one(mask size 45)(p<0.05). By using this analytic approach, an optimal parameter in digital chest radiography may be investigated in many other forms of pulmonary disease such as pulmonary nodule or mediastinal mass.

의학자가 바라는 도서관 : 의사들의 정보요구와 이용에 대하여

정은철 한국의학도서관협회 1998 한국의학도서관 Vol.25 No.2