Magnetic resonance images of ameloblastoma

Kim, Jae-Duk,Kim, Jin-Soo 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.4

Purpose : To classify and describe the characteristic features of MRI of some ameloblastoma variants. Materials and Methods : The MR images, CT images, and panoramic radiographs in 5 cases were retrospectively examined as follows. First, the contents of ameloblastomas were devided into two portions of either solid or cystic components on the basis of MR signal intensities. The signal intensity within the solid or cystic portions was classified as homogeneous or heterogeneous. Next, the characteristic internal feature of the lesion on T1W1 or T2WI was described. The signal intensities were classified into low, intermediate, slightly high, high, and strong high signal intensity. Results : Unicystic lesion showed homogeneous high signal intensity (SI) on T2W2 and the rim enhancement of the surrounding area including the mural nodule and the thick wall except the central portion on Gd-T1W1 Solid type revealed heterogeneous and high SI area with strong high SI area on T2W2. On Gd-T1W1, the area corresponding to the low signal spot on T1W1 and the strong high signal spot on T2W1 showed low SI. Hybrid type showed slightly enhanced capsular structures and low SI for the round bony septa and the areas connecting the mixed and cystic lesions on T2W1 and Gd-T1W1. Conclusion : MRI could easily assess the relationship between the mixed and cystic findings in ameloblastoma.

급성 심근허혈에 의해 윤발된 승모판 폐쇄부전의 기전에 관한 실험적 연구

강덕현,송현,송재관,김현숙,이재환,임희영,이재원,박성욱,박승정,송명근 대한순환기학회 1999 Korean Circulation Journal Vol.29 No.8

판막 질환에서의 심근 섬유화 : 심근 조직을 이용한 형태학적 연구 및 혈청 생화학적 지표의 분석

강수진,박덕우,송재관,박경민,송종민,강덕현,한기훈,송현,이재원,주석중,송명근,김정선 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.2

알쯔하이머 환자의 실행증 오류 형태

권재철,나덕렬,김향희,김경문,강연욱 대한신경과학회 1997 대한신경과학회지 Vol.15 No.5

경막내로 투여한 신경전달물질이 통증성 배뇨반사에 미치는 영향

박재식,김덕윤,안동국 大韓泌尿器科學會 1998 Korean Journal of Urology Vol.39 No.8

하지에 발생한 악성 흑생종의 치료

유재덕,이병민,탁관철 大韓成形外科學會 1993 Archives of Plastic Surgery Vol.20 No.3

Malignant melanoma is uncommon but very poor prognostic malignant disease of melanocytic origin. Rate of occurence in lower extremity is varying from 27.9% to 36.7%. The authors have experienced 10 cases of malignant melanoma in lower extremity. Most common site in lower extremity was the heel pad. Sex ratio was 2 : 3 with preponderance to women and the average age was 56.8 yr. Most patients presented with progressed stage of disease : Clark level was Ⅳ in 3 cases, level Ⅴ in 5 cases, the lesions invaded into maximal depth of more than 5mm in 9 cases. Pathological examination showed 5 cases of nodular type and 5 cases of acral lentiginous type. Defects developed after wide excision were managed with simple primary closure in digit, skin graft to non weight bearing sole and calf area, medial plantar island flap or free flap transfer in heels. In 2 cases, postoperative adjuvant therapy with combined chemotherapy(KTIC, DDP, Tamoxifen) or immunotherapy with Lymphokine activated killer cell was pursued.

칼라영상 입 ·출력 시스템의 칼라보정 알고리듬에 관한 고찰

신현덕,김일태,임재권,윤동한 國立金烏工科大學校附設生産技術硏究所 1995 産業技術開發硏究 Vol.11 No.-

Colors reprodued by color image processing system are affected by various physical factors and environmental conditions. Therefore it is difficult to reproduce the original object color accurately. Thus color calibrations of the input and output data of color image processing system based on spectral distributions are required. We propose a color calibration algorithm by considering spectral characteristic of the chosen color reproduction system which can be applied to device independent color reproduction using characteristic vectors of surface reflectance. The method comprised of two steps. The first step is color analysis step which reproduces the original object color from the camera output using color characteristic vectors. The second step is color synthesis step which displays the original color accurately on the monitor by considering the monitor's phosphor spectra. The spectral responsivities of camera sensors and phosphor spectral characteristics of a given monitor are evaluated. Also, to evaluate color reproducing characteristic we applied the proposed color calibration algorithm by choosing Macbeth ColorChecker's twenty four color spectra as a test color set. As a result, we reconstruct the actual color very closely on monitor using the proposed color calibration algorithm.

디지탈영상에서 골판톰의 프랙탈분석

김재덕,김진수,이창율 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.1

Purpose : (1) To analyse the effect of exposure time, ROI size and one impact factor in the image processing procedure on estimates of fractal dimension; and (2) to analyse the correlated relationship between the fractal dimension and the Cu-Eq value (bone density). Materials and Methods : The cylindric bone phantoms of 6 large and 5 small diameter having different bone densities respectively and human dry mandible segment with copper step wedge were radiographed at 1.0 and 1.2 sec esposure (70 kVp, 7 mA) using one occlusal film and digitized. Eleven rectangular ROIs from 11 cylindric bone phantoms and 4 rectan-gular ROIs from cortical, middle, periodontal regions, and socket of bone were selected. Gaussian blurred Image was subtracted from original image of each ROI and multiplied respectively by 1, 0.8, and 0.5, and then the image was made binary, eroded and dilated once, and skeletonized. The fractal dimension was calculated by means of a box counting method in the software ImageJ. Results : The fractal dimension was decreased gradually with continued bone density decrease showing strong correlations (bone phantom; r>0.87, bone; r>0.68) under 70 kVp 1.0 sec M = 0.8. Fractal dimensions showed the significant differerence (p<0.05) between two different exposure times on the same small ROI of bone phantom. Fractal dimensions between two different sizes of ROI on bone phantom showed the significant differerence (p<0.05) under 1.2 sec exposure, but did not show it (p>0.05) under 1.0 sec exposure. Conclusions : Exposure time, ROI size, and modifying factor during subtracting could become impacting on the results of fractal dimension. Fractal analysis with thoroughly evaluated method considering the various impacting factors on the results could be useful in assessing the bone density in dental radiography.

Digora 에서 정량영상의 특성에 대한 평가

김재덕 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.2

Purpose : To clarify the usefulness and the limitation of Digora system by evaluating the physical characteristics as the quantitative image on Image Plate(IP). Materials and Methods : Radiograms were taken by Heliodent MD(Siemens Co., Germany) with the image plate for adult, Cu-step wedge as reference material, and three pieces of dry mandibular bone. Image analysis was performed by single color enhancement, density measurement with histogram. The relationship between the exposure conditions and the distribution of the pixel values of the image, the variation of pixel values of each step of Cu-step wedge at two different area and Cu-equivalent value of three pieces of dry mandibular bone measure by the conversion equation. Results : There was no linear relationship between the exposure condition and the average pixel value of the image, of which the distribution was not even. The pixel value differences between the center portion and the periphery were ranged from 60 to 70 in vertical plane and from 15 to 26 in horizontal plane. Two plot profile formed at two different areas of the Cu-step wedge were different. The measured Cu-equivalent values showed the discrepancy among the times of measurement. Conclusion : As above results, Image Plate(IP) of Digora system showed the limitation as the quantitative image. The physical property of IP was expected to need to be compensated for the quantitative evaluation of the bone or others(J Korean Oral Maxillofac Radiol 1999;29:397-406)

Digora 영상시스템을 이용한 인접면 인공 치아우식병소의 진단능에 관한 연구

김재덕,오경란,최의환 大韓口腔顎顔面 放射線學會 1998 Imaging Science in Dentistry Vol.28 No.2

Digora system is an intraoral indirect digital radiography system utilizing storage phosphor image plate. It has wide dynamic range which allows it to decrease the patient's exposure time and may increase diagnostic ability through image processing (such as edge enhancement, grey scale conversion, brightness change, and contrast enhancement). And also, ti can transmit and storage image information. The purpose of this study was to evaluate the diagnostic ability of artificial proximal caries between Conventional radiograph and Digora images(unenhanced image, brightness & contrast controlled image, and edge enhanced image). ROC(Receiver Operating Characteristic) analysis, paired t-test, and F-tests were done for the statistical evaluation of detectability. The following results were acquired: 1. In Grade I lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.953, 0.933, 0.965, 0.978 (p>0.05). 2. In Grade II lesions, the mean ROC areas of Conventional radiograph, Digora unenhanced image, Digora controlled image, and Digora edge enhanced image were 0.969, 0.964, 0.988, 0.994. Among theses areas, there was just statistical significance between Diagnostic abilities of Digora edge enhanced image and Conventional rediograph(p<0.05). 3. In the Interobserver variability, the ROC curve areas of Digora edge enhanced image was lowermost in these areas, regardless of the Carious lesion depths. In conclusion, intraoral indirect digital system, Digora system has the potential possibility as an alternative of Conventional radiograph in the diagnosis of proximal caries.