단층촬영 각도의 변화가 하악과두의 골 증식성 병소의 인식에 미치는 영향

김기덕,한상선 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1

Purpose: To find out the effects that different tomographic angles have on the osteophytic lesion detectability of condyle head by comparison the individualized lateral tomographic image with the various tomographic angled images using SCANORA . Materials & Methods: This study is performed to simulate osteophytic lesions by a series of dentin chips placed at six locations on condyle head. The control angle is 15°and from this angle, tomographic angle were varied with -10°, +10°+20°. All the images with each sized dentin chip were scored by three dental radiologists with the use of confidence levels for presence or absence of the lesion, each examiner viewed one of the images twice. A rating scale from 0 to 2 (0, lesion definitely not present; 1, uncertain if lesion is present; 2, lesion definitely present). Responses were assessed by Tukey's multiple comparison method and kappa value. Results: 1. The lesion size of 0.3mm could not be detected in all the tomographic angles. As the size of the lesion increased the average value of lesion detectability also increased. 2. In the lesion sizes of 0.7mm there was statistically significant difference between the 15°control angle and the altered tomographic angles (p<0.05). In 1.0mm lesion there was no significant difference in the ±10°altered angles (p<0.05), but there was significant difference in the altered angle(p<0.05). In the lesion sizes of 0.3mm and 2.0mm there was no significant difference between the 15°control angle and all the altered angle(p>0.05). 3. In the anteromedial, anterosuperior, anterolateral area there was no significant difference between the 15°control angle and the ±10°altered angle(p>0.05), but in the comparison with the +20°alterd angle there was significant difference(p>0.05). Conclusion: When imaging the lateral tomography of the temporomandibular joint used by SCANORA, it can be considered that in the osteophytic lesion size of 2mm and above, the tomographic angle difference within +20°to the horizontal angle of the condyle, has little effect on the lesion detectability. And in the lesion size of 1mm, the altered angle within ±10°also has little effect on the lesion detectability.

약관절원판 천공의 방사선학적 연구

김기덕,박창서 大韓口腔顎顔面 放射線學會 1990 Imaging Science in Dentistry Vol.20 No.2

Thirty-nine patients (forty-four joints) who had been diagnosed as having meniscus perforation of the temporomandibular joint by inferior joint space arthrography and had been treated by surgical procedures were evaluated retrospectively. Information of clinical findings, arthrotomographic findings and surgical findings was collected on a standardized form and evaluated. The results were as follows : 1. On the 34 patients of 38 joints which were surgically confirmed perforation of meniscus or its attachments of the temporomandibular joint, there were 29 females and 5 males(5.8:1). The average age was 36 years(range 17 to 70). 2. The common clinical findings of group that had meniscus displacement without reduction and with perforation were pain on the affected joint and limitation of mouth opening. In the group showing meniscus displacement with reduction and with perforation the common clinical findings were pain and clicking on the affected joint. 3. 32 joints(84.2%) were arthrotomographically anterior meniscus displacement without reduction and with perforation, 6 joints(15.8%) showed anterior meniscus displacement with reduction and with perforation. 4. Joints categorized arthrotomographically as having meniscus displacement without reduction and with perforation were less likely to have full translation of the condyle in comparison with the normal or meniscus displacement with reduction and with perforation groups.(p<005) 5. The arthrographic findings of 44 joints having meniscus perforation were compared with surgical findings, there were 6 false positive findings of meniscus perforation, the reliability of arthrographic findings of meniscus perforation was a 86.4% correlation with surgical findings. 6. On the site of perforations of 38 joints which were surgically confirmed perforation of meniscus or its attachments, twenty-three of perforations(60.5%) were in location at the junction of the meniscus and posterior attachment, forteen(36.9%) were located at the posterior attachment and one (2.6%) was at the meniscus itself.

영상재구성 전산화 단층촬영에서 촬영조건의 변화가 하악골 술전 임플란트 부위 평가에 미치는 영향

김기덕,박창서 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.1

Purpose: To evaluate the effect of variable scanning protocols of computed tomography for evaluation of pre-implant site of the mandible through the comparison of the reformatted cross-sectional images of helical CT scans obtained with various imaging parameters versus those of conventional CT scans. Materials and Methods: A dry mandible was imaged using conventional nonoverlapped CT scans with 1 mm slice thickness and helical CT scans with 1 mm slice thickness and pitches of 1.0, 1.5, 2.0, 2.5 and 3.0. All helical images were reconstructed at reconstruction interval of 1 mm. DentaScan reformatted images were obtained to allow standardized visualization of cross-sectional images of the mandible. The reformatted images were reviewed and measured separately by 4 dental radiologists. The image qualities of continuity of cortical outline, trabecular bone structure and visibility of the mandibular canal were evaluated and the distance between anatomic structures were measured by 4 dental radiologists. Results: On image qualities of continuity of cortical outline, trabecular bone structure and visibility of the mandibular canal and in horizontal measurement, there was no statistically significant difference among conventional and helical scans with pitches of 1.0, 1.5 and 2.0. In vertical measurement, there was no statistically significant difference among the conventional and all imaging parameters of helical CT scans with pitches of 1.0, 1.5, 2.0, 2.5 and 3.0. Conclusion: The images of helical CT scans with 1 mm slice thickness and pitches of 1.0, 1.5 and 2.0 are as good as those of conventional CT scans with 1 mm slice thickness for evaluation of predental implant site of the mandible. Considering the radiation dose and patient comfort, helical CT scans with 1 mm slice thickness and pitch of 2.0 is recommended for evaluation of pre-implant site of the mandible.(J Korean Oral Maxillofac Radiol 1999:29:21-32)

나이에 따른 한국인 정상 이하선의 전산화단층촬영값의 차이

박창서,김기덕,이은숙,정호걸 大韓口腔顎顔面 放射線學會 1999 Imaging Science in Dentistry Vol.29 No.2

Purpose : To determine normal CT number range of parotid gland by analyzing the change by age increase and the difference among individuals and between both sexes in CT number of normal parotid gland. Materials & Methods : 134 subjects who took the CT scan between the period of Jan. 1996 and Dec. 1997 at Yonsei University, Dental Hospital were selected. Criteria for selection were that the patients must be within the normal range clinically and radiologically, and the entire parotid gland on the axial view must be shown. Among the axial views, the one showing the greatest parotid gland size was selected and its CT number was recorded. Also, CT numbers from both masseter muscle were recorded as its control. Results : There was statistically significant correlation between CT number of right and left of parotid glands and masseter muscles. With the increase of age, there is a significant decrease in the CT number of parotid gland(p<0.05). There was no statistically significant difference in CT number between sexes except the 7th decade and beyond age group of parotid gland(p>0.05). Conclusion : As age increases, CT number of parotid gland has a tendency to decrease, and there is no significant difference in the CT numbers between left and right parotid gland. Therefore in the CT scan of patients suspected of having a salivary gland disease of the parotid gland, to consider normal range of the age-dependent CT numbers of parotid gland and compare the CT numbers of the right and left parotid gland might be useful in diagnosing the disease.(J Korean Oral Maxillofac Radiol 1999;29:451-458)

3차원 전산화단층촬영 영상을 이용한 얼굴 연조직 두께 계측

정호걸,김기덕,한승호,신동원,허경석,이제범,박혁,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.37 No.1

Purpose : To evaluate accuracy and reliability of program to measure facial soft tissue thickness using 3D computed tomographic images by comparing with direct measurement. Materials and Methods : One cadaver was scanned with a Helical CT with 3 mm slice thickness and 3 mm/sec table speed. The acquired data was reconstructed with 1.5 mm reconstruction interval and the images were transferred to a personal computer. The facial soft tissue thickness were measured using a program developed newly in 3D image. For direct measurement, the cadaver was cut with a bone cutter and then a ruler was placed above the cut side, The procedure was followed by taking pictures of the facial soft tissues with a high-resolution digital camera. Then the measurements were done in the photographic images and repeated for ten times. A repeated measure analysis of variance was adopted to compare and analyze the measurements resulting from the two different methods. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant differences between the direct measurements and those using the 3D images (p>0.05). There were statistical differences in the measurements on 17 points but all the points except 2 points showed a mean difference of 0.5 mm or less. Conclusion : The developed software program to measure the facial soft tissue thickness using 3D images was so accurate that it allows to measure facial soft tissues thickness more easily in forensic science and anthropology. (Korean J Oral Maxillofac Radiol 2006; 36 : 49-54)

전산화단층촬영 단말장치와 개인용 컴퓨터에서 재구성한 두부 3차원 전산화단층영상의 비교

강복희,김기덕,박창서 대한구강악안면방사선학회 2001 Imaging Science in Dentistry Vol.31 No.1

Purpose : To evaluate the usefulness of the reconstructed 3-dimensional image on the personal computer in comparison with that of the CT workstation by quantitative comparison and analysis. Materials and Methods : The spiral CT data obtained from 27 persons were transferred from the CT workstation to a personal computer, and they were reconstructed as 3-dimensional image on the personal computer using V-works 2.OTM. One observer obtained the 14 measurements on the reconstructed 3-dimensional image on both the CT workstation and the personal computer. Paired t-test was used to evaluate the intraobserver difference and the mean value of the each measurement on the CT workstation and the personal computer. Pearson correlation analysis and % incongruence were also performed. Results : I-Gn, N-Gn, N-A, N-Ns, B-A, and G-Op did not show any statistically significant difference (p)0.05), B-O, B-N, Eu-Eu, Zy-Zy, Biw, D-D, Orbrd R, and L had statistically significant difference(p〈0.05), but the mean values of the differences of all measurements were below 2 mm, except for D-D. The value of correlation coefficient γ was greater than 0.95 at I-Gn, N-Gn, N-A, N-Ns, B-A, B-N, G-Op, Eu-Eu, Zy-Zy, and Biw, and it was 0.75 at B-O, 0.78 at D-D, and 0.82 at both Orbrd R and L. The % incongruence was below 4% at I-Gn, N-Gn, N-A, N-Ns, B-A, B-N, G-Op, Eu-Eu, Zy-Zy, and Biw, and 7.18%, 10.78%, 4.97%, 5.89% at B-O, D-D, Orbrd R and L respectively. Conclusion : It can be considered that the utilization of the personal computer has great usefulness in reconstruction of the 3-dimensional image when it comes to the economics, accessibility and convenience, except for thin bones and the landmarks which are difficult to be located.(Korean J Oral Maxillofac Radiol 2001;31:1-7)

악골에 발생한 석회화 치성낭의 임상 및 방사선학적 고찰

박창서,김기덕,윤혜림 大韓口腔顎顔面放射線學會 1996 Imaging Science in Dentistry Vol.26 No.2

Nine cases presented with a calcifying odontogenic cyst to the Dental Hospital of the College of Dentistry, Yonsei University, from January 1987 to September June, 1996, Clinical or histopathological findings were observed according to each radiologic criteria. The results obtained are as follows: 1. The male to female ratio was 2:1 with a mean age of 25 years. 2. The radiographic appearences of nine cases were well-defined radiolucent lesions in which eight cases were shown unilocular lesions and only one lesion was seen multilocular lesion. 3. Radiologically, three of nine cases were pure radiolucent lesions and others, six cases were radiolucent contained a variable amount of radiopaque material. 4. Histologically, two cases were classified simple cyst, five were cyst associated odonoma, two were neoplastic type. 5. Histlolgical findings according to the radiological classification, two of three radiolucenct lesions were simple cysts; another was a cyst associated with odontoma. While, four of six radiologic mixed lesions turned out to be a cyst associated with odontoma, two was the neoplastic type.

두개골의 3차원 영상 분석을 위한 전산화단층촬영 방법의 비교 : 상층 두께가 3차원 영상의 계측에 미치는 영향

정호걸,김기덕,박혁,김동욱,정해조,김희중,유선국,김용욱,박창서 대한구강악안면방사선학회 2004 Imaging Science in Dentistry Vol.34 No.3

Purpose : To evaluate the quantitative accuracy of three-dimensional (3D) images by means of comparing distance measurements on the 3D images with direct measurements of dry human skull according to slice thickness and scanning modes. Materials and Mathods : An observer directly measured the distance of 21 line items between 12 orthodontic landmarks on the skull surface using a digital vernier caliper and each was repeated five times. The dry human skull was scanned with a Helical CT with various slice thickness (3, 5, 7 mm) and acquisition modes (Conventional and Helical). The same observer measured corresponding distance of the same items on reconstructed 3D images with the internal program of V-works 4.0 (Cybermed Inc., Seoul, Korea). The quantitative accuracy of distance measurements were statistically evaluated with Wilcoxons’ two-sample test. Results : 11 line items in Conventional 3 mm, 8 in Helical 3mm, 11 in Conventional 5 mm, 10 in Helical 5 mm, 5 in Conventional 7 mm and 9 in Helical 7 mm showed no statistically significant difference. Average difference between direct measurements and measurements on 3D CT images was within 2 mm in 19 line items of Conventional 3 mm, 20 of Helical 3 mm, 15 of Conventional 5 mm, 18 of Helical 5 mm, 11 of Conventional 7mm and 16 of Helical 7 mm. Conclusion : Considering image quality and patient’s exposure time, scanning protocol of Helical 5 mm is recommended for 3D image analysis of the skull in CT.

3차원 전산화단층촬영 영상을 이용한 안면 연조직 두께 계측의 임상적 유용성

정호걸,김기덕,한승호,허경석,이제범,박혁,최성호,김종관,박창서 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.2

Purpose : To evaluate clinical usefulness of facial soft tissue thickness measurement using 3D computed tomographic images. Materials and Methods : One cadaver that had sound facial soft tissues was chosen for the study. The cadaver was scanned with a Helical CT under following scanning protocols about slice thickness and table speed; 3 mm and 3 mm/sec, 5 mm and 5 mm/sec, 7 mm and 7 mm/sec. The acquired data were reconstructed 1.5, 2.5, 3.5 mm reconstruction interval respectively and the images were transferred to a personal computer. Using a program developed to measure facial soft tissue thickness in 3D image, the facial soft tissue thickness was measured. After the ten-time repeation of the measurement for ten times, repeated measure analysis of variance (ANOVA) was adopted to compare and analyze the measurements using the three scanning protocols. Comparison according to the areas was analyzed by Mann-Whitney test. Results : There were no statistically significant intraobserver differences in the measurements of the facial soft tissue thickness using the three scanning protocols (p>0.05). There were no statistically significant differences between measurements in the 3 mm slice thickness and those in the 5 mm, 7 mm slice thickness (p>0.05). There were statistical differences in the 14 of the total 30 measured points in the 5 mm slice thickness and 22 in the 7mm slice thickness. Conclusion : The facial soft tissue thickness measurement using 3D images of 7 mm slice thickness is acceptable clinically, but those of 5 mm slice thickness is recommended for the more accurate measurement.

상층두께와 관심영역의 크기 변화가 CT번호에 미치는 영향

이지연,김기덕,박창서 대한구강악안면방사선학회 2001 Imaging Science in Dentistry Vol.31 No.2

Purpose : To evaluate the effect of the slice thickness and the size of region of interest (ROI) on CT number using quantitative CT phantom Materials and Methods : The phantom containing 150 mg/cc, 75 mg/cc and 0 mg/cc calcium hydroxyapatite was scanned with 1,3,5 and 10 mm slice thicknesses by single energy quantitative computed tomography (QCT). CT numbers were measured on center position of the phantom. Shape of ROI was circular and sizes were 1, 3, 5, 11, 16, 21, 26 and 33 mm2. ANOVA and Tukey's multiple comparison method were performed for statistical comparison of CT numbers according to different slice thicknesses. Coefficient of variation of CT number measured in each size of ROI was evaluated in same slice thickness. Results : CT numbers had statistically significant difference according to slice thicknesses (p〈0.05), As the slice thickness increased, CT number also increased. As the density of phantom became lower and the size of ROI became smaller, the coefficient of variation of CT number increased. When the size of ROI was more than 11 mm2 in 1 mm slice thickness, 5 mm2 in 3 mm slice thickness and 3 mm2 in 5 mm slice thickness, the coefficient of variation became consistent. In 10 mm slice thickness, the size of ROI had little effect on the coefficient of variation. Conclusion : CT number had variation according to the slice thickness and the size of ROI although the object was homogeneous. The slice thickness and the size of ROI are critical factors in precision of the CT number measurements.(Korean J Oral Maxillofac Radiol 2001;31:85-91)