영상보간법을 이용한 디지털 치근단 방사선영상의 개선에 관한 연구

송남규,고광준,Song Nam-Kyu,Koh Kawng-Joon 대한영상치의학회 1998 Imaging Science in Dentistry Vol.28 No.2

Image resampling is of particular interest in digital radiology. When resampling an image to a new set of coordinate, there appears blocking artifacts and image changes. To enhance image quality, interpolation algorithms have been used. Resampling is used to increase the number of points in an image to improve its appearance for display. The process of interpolation is fitting a continuous function to the discrete points in the digital image. The purpose of this study was to determine the effects of the seven interpolation functions when image resampling in digital periapical images. The images were obtained by Digora, CDR and scanning of Ektaspeed plus periapical radiograms on the dry skull and human subject. The subjects were exposed to intraoral X-ray machine at 60kVp and 70 kVp with exposure time varying between 0.01 and 0.50 second. To determine which interpolation method would provide the better image, seven functions were compared; (1) nearest neighbor (2) linear (3) non-linear (4) facet model (5) cubic convolution (6) cubic spline (7) gray segment expansion. And resampled images were compared in terms of SNR(Signal to Noise Ratio) and MTF(Modulation Transfer Function) coefficient value. The obtained results were as follows ; 1. The highest SNR value(75.96dB) was obtained with cubic convolution method and the lowest SNR value(72.44dB) was obtained with facet model method among seven interpolation methods. 2. There were significant differences of SNR values among CDR, Digora and film scan(P<0.05). 3. There were significant differences of SNR values between 60kVp and 70kVp in seven interpolation methods. There were significant differences of SNR values between facet model method and those of the other methods at 60kVp(P<0.05), but there were not significant differences of SNR values among seven interpolation methods at 70kVp(P>0.05). 4. There were significant differences of MTF coefficient values between linear interpolation method and the other six interpolation methods (P< 0.05). 5. The speed of computation time was the fastest with nearest -neighbor method and the slowest with non-linear method. 6. The better image was obtained with cubic convolution, cubic spline and gray segment method in ROC analysis. 7. The better sharpness of edge was obtained with gray segment expansion method among seven interpolation methods.

디지털방사선촬영법을 이용한 치조골벽 소실에 관한 실험적 연구

송남규,고광준,Song Nam-Kyu,Koh Kwang-Joon 대한영상치의학회 1997 Imaging Science in Dentistry Vol.27 No.2

The purpose of this study was to compare E-speed film, CDR, and modified CDR images by means of observing some artificial defects of alveolar bone wall in the sound human dried mandibles. High diagnostic accuracy was shown in 1 wall and 4 wall defects by all 5 observers (2 Radiologists, 2 Periodontists, 1 General practitioner), but the diagnosis in 2 wall and 3 wall defects was inaccurate. Modified CDR images had the more diagnostic accuracy than E-speed film and CDR images, but there was no statistical difference among them. Finally, radiologist used modified CDR images more than others and used equalization effect more than the change in contrast and/or brightness.

상악동염에 관한 방사선학적 비교 연구

송남규,고광준,Song Nam-Gyu,Koh Kwang-Joon 대한영상치의학회 1997 Imaging Science in Dentistry Vol.27 No.1

The purpose of this study was to evaluate the Waters' views, panoramic and periapical radiograms as well as clinical symptoms in the diagnosis of maxillary sinusitis. The author analyzed the types of mucosal thickenings, the types of bony wall changes, the pathologic changes of antral floors and total amount of agreement on radiograms in 495 patients with 505 maxillary sinuses which demonstrated radiographic changes. The results were obtained as follows : 1. 125 cases (24.8%) showed the mucosal thickening of antral floor and lateral wall (Type II), 106 cases (20.9%) showed the mucosal thickening around the whole antral wall (Type N) and 75 cases (14.8%) showed increased radiopacity of whole antrum. 2. Among 505 cases of mucosal thickenings, 319 cases<63.2%) showed the bony wall changes: 114 cases (35.9%) showed the thinning of lateral walls, 105 cases (32.8%) showed the thickening of lateral walls and 47 cases(14.7%) showed indistinct antral walls. 3. Among 6 types of mucosal thickenings, the incidence of bony wall changes was high in type VI(73.3%) and in type IV(71.6%). 4. 139 cases(25.1%) showed no pathologic change of antral floor, 127 cases(22.9%) showed the indistinct antral floor and 122 cases (22.1%) showed the halo appearance of antral floor on panoramic and periapical radiograms. 5. 449 cases (88.9%) showed apparent increased radiopacity and 47 cases(9.3%) showed suspicious increased radiopacity on Waters' views. 280 cases (71.6%) showed apparent increased radiopacity and 88 cases (22.5%) showed suspicious increased radiopacity on panoramic radiograms. And 141 cases (31.6%) showed apparent increased radiopacity and 133 cases(33.4%) showed suspicious increased radiopacity on periapical radiograms.

전산화단층상을 이용한 안면골의 3차원재구성상의 비교 연구

송남규,김민숙,고광준 全北大學校 齒醫學硏究所 1992 전북치대논문집 Vol.10 No.1

The purpose of this study was to evaluate the spatial relationship of facial bone more accurately. For this study, the three-dimensional images of dry skull were reconstructed using computer image analysis system and three-dimensional reconstructive program involved CT. The obtained results were as follows : 1. Three-dimensional reconstructive CT results in images that have better resolution and more contrast. 2. It showed good marginal images of anatomical structure on both three-dimensional CT and computer image analysis system, but the roof of orbit, the lacrimal bone and the squamous portion of temporal bone were hardly detectable. 3. The partial loss of image data were observed during the regeneration of saved image data on three-dimensional CT. 4. It saved the more time for reconstruction of three-dimensional images using computer image analysis system. But, the capacity of hardware was limited for inputting of image data and three-dimensional reconstructive process. 5. We could observe the spatial relationship between the region of interest and the surrounding structures by three-dimensional reconstructive images without invasive method.

악교정 수술 후 하악과두의 위치 및 골변화에 관한 단층방사선학적 연구

송남규,김민숙,고광준 全北大學校 齒醫學硏究所 1992 전북치대논문집 Vol.10 No.1

The purpose of this study was to aid in the evaluation of prognosis of temporomandibular joint following orthognathic surgery. For this study, 20 patients(40 TMJ) who had undergone orthognathic surgery were examined. Preoperative and postoperative tomograms of TMJ were taken. And the subjects were divided into 3 groups according to postoperative periods. The results were as follows ; 1. There were no significant differences between preoperative and postoperative changes in joint spaces in each group and between groups(P<0.05). 2. There were no significant differences between preoperative and postoperative ratio of joint space(P<0.05). 3. There were no significant differences between preoperative and postoperative changes in the range of motion of condylar head(P<0.05). 4. The bony changes of condylar head were observed in 14(35% ) condyles(6 erosion, 2 flattening, 5 double contour, 1 osteophyte).

경계강조 보간법을 이용한 디지털방사선사진상의 개선에 관한 연구

송남규,고광준,Song Nam-Kyu,Koh Kwang-Joon 대한영상치의학회 1998 Imaging Science in Dentistry Vol.28 No.1

The purpose of this study was to aid in the use of the digital images by edge-detect interpolation for direct digital periapical images using edge-detect interpolation. This study was performed by image processing of 20 digital periapical images; pixel replication, linear non-interpolation, linear interpolation. and edge-sensitive interpolation. The obtained results were as follows : 1. Pixel replication showed blocking artifact and serious image distortion. 2. Linear interpolation showed smoothing effect on the edge. 3. Edge-sensitive interpolation overcame the smoothing effect on the edge and showed better image.

전산화단층사진상을 이용한 하악관의 위치 및 하악골의 피질골 두께에 관한 연구

하쌍용,고광준,송남규 大韓口腔顎顔面 放射線學會 1997 Imaging Science in Dentistry Vol.27 No.1

The location of the mandibular canal and the cortical thickness of the mandible is important in the practice of dentistry. This study was performed on twenty chosen dry mandibles, which were of adults and included fully erupted premolars and molars. The purpose of this study was to evaluate the location of the mandibular canal and the cortical thickness of the mandible on computed tomograms and to aid in the surgical treatment plans. The obtained results were as follows; 1. The horizontal distance between the mandibular canal and the buccal external border was 6.6±0.9mm on S?(mesial root of the first molar),and it was increased posteriorly. The horizontal distance between the mandibular canal and the lingual external border was 4.1±1.1mm on S?, and it was decreased posteriorly. 2. The vertical distance between the alveolar crest and the mandibular canal was 16.9±1.6mm on S?, and it was decreased posteriorly. The vertical distance between the inferior border of mandible and the mandibular canal was 8.8±1.3mm on S?, and it was increased anteriorly and posteriorly. 3. The thickness of the buccal cortical plate was 2.2±0.4mm on S?. and it was increased posteriorly. But, that of the lingual cortical plate was 2.0±0.6mm on S? and it was decreased posteriorly. 4. The area of the buccal cortical plate was 66.5±1.0mm²on S? and it was increased posteriorly. But, that of the lingual cortical plate was 65.8±0.9mm²on S? and it was decreased posteriorly.

악교정 수술 후 하악과두의 위치 및 골변화에 관한 단층방사선학적 연구

송남규,고광준,김민숙 大韓口腔顎顔面 放射線學會 1992 Imaging Science in Dentistry Vol.22 No.2

The purpose of this study was to aid in the evaluation of prognosis of temporomandibular joint following orthognathic surgery. For this study, 20 patients(40 TMJ) who undergone orthognathic surgery were examined. Preoperative and postoperative tomograms of TMJ were taken. And the subjects were divided into 3 groups according to postoperative periods. The obtained results were as follows ; 1. There were no significant differences between preoperative and postoperative changes in joint spaces in each group and between groups(p<0.05). 2. There were no significant differences between preoperative and postoperative ratio of joint space(p<0.05). 3. There were no significant differences between preoperative and postoperative changes in the range of motion of condylar head(p<0.05). 4. The bony changes of condylar head were observed in 14(35%) condyles(6 erosion, 2 flattening, 5 double contour, 1 osteophyte).

전산화단층상을 이용한 안면골의 3차원재구성상의 비교연구

송남규,고광준 大韓口腔顎顔面 放射線學會 1992 Imaging Science in Dentistry Vol.22 No.2

The purpose of this study was to evaluate the spatial relationship of facial bone more accurately. For this study, the three-dimensional images of dry skull were reconstructed using computer image analysis system and three-dimensional reconstructive program involved CT. The obtained results were as follows ; 1. Three-dimensional reconstructive CT results in images that have better resolution and more contrast. 2. It showed good marginal images of anatomical structure on both three-dimensional CT and computer image analysis system. but the roof of orbit, the lacrimal bone and the squamous portion of temporal bone were hardly detectable. 3. The partial loss of image date were observed during the regeneration of saved image data on three-dimensional CT. 4. It saved the more time for reconstruction of three-dimensional images using computer image analysis system. But, the capacity of hardware was limited for imputting of image data and three-dimensional reconstructive process. 5. We could observe the spatial relationship between the region of interest and the surrounding structures by three-dimensional reconstructive images without invasive method.

경계강조 보간법을 이용한 디지탈방사선사진상의 개선에 관한 연구

송남규,고광준 大韓口腔顎顔面 放射線學會 1998 Imaging Science in Dentistry Vol.28 No.1

The purpose of this study was to aid in the use of the digital images by edge-detect interpolation for direct digital periapical images using edge-detect interpolation . This study was performed by image processing of 20 digital periapical images; pixel replication, linear non-interpolation, linear interpolation, and edge-sensitive interpolation. The obtained results were as follows: 1. Pixel replication showed blocking artifact and serious image distortion. 2. Linear interpolation showed smoothing effect on the edge. 3. Edge-sensitive interpolation overcame the smoothing effect on the edge and showed better image.