구내 표준 방사선사진을 이용한 구내방사선촬영기의 선질 평가

이상섭,권혁락,심우현,오승현,이지연,전국진,김기덕,박창서 대한구강악안면방사선학회 2000 Imaging Science in Dentistry Vol.30 No.3

Purpose : This study was to evaluate the beam quality of intraoral X-ray equipments used at Yonsei University Dental Hospital (YUDH) using the half value layer (HVL) and the characteristic curve of intraoral standard X-ray film. Materials and Methods : The study was done using the intraoral X-ray equipments used at each clinical department at YUDH. Aluminum filter was used to determine the HVL. Intraoral standard film was used to get the characteristic curve of each intraoral X-ray equipment. Results : Most of the HVLs of intraoral X-ray equipments were higher than the least recommended thickness, but the REX 601 model used at the operative dentistry department and the X-707 model used at the pediatric dentistry department had HVLs lower than the recommended thickness. The slopes of the characteristic curves of films taken using the PANPAS 601 model and REX 601 model at operative dentistry department, the X-705 model of prosthodontic dentistry department, and the REX601 model at the student clinic were relatively low. Conclusion : HVL and the characteristic curve of X-ray film can be used to evaluate the beam quality of intraoral X-ray equipment. In order to get the best X-ray films with the least radiation exposure to patients and best diagnostic information in clinical dentistry, X-ray equipment should be managed in the planned and organized fashion. (Korean J Oral Maxillofac Radiol 2000; 30: 183-188)

구내방사선사진의 인접면 치아우식 진단에 대한 유용성 평가

김영희,강병철 대한구강악안면방사선학회 2000 Imaging Science in Dentistry Vol.30 No.1

Purpose : To compare the diagnostic performance of clinical and radiologic examination for the interproximal caries on intraoral periapical radiographs and to evaluate the value of periapical radiographs. Methods : One hundred seven dental patients were examined clinically, with a mouth mirror and an explorer, by a dentist at the department of oral medicine, and the presence or absence of interproximal caries lesion was recorded. The patients were prescribed one or more dental peuapical radiographs. Radiographs were assessed for the presence of interproximal caries by three oral and maxillofacial radiologists independently. Two thousand sixty interproximal surfaces were included in this study. The diagnostic accuracies of clinical and radiologic examinations for interproximal caries were calculated. To assess the degree of agreement between clinical and radiologic examinations, Cohen's coefficient of agreement was computed. Results : The specificity of clinical and radiologic examination was 0.991,0.997 and the sensitivity was 0.279, 0.985 respectively. The diagnostic accuracy of radiologic examination was statistically significantly higher than that of clinical examination (P< 0.05). Cohen's kappa value of clinical and radiologic examination was 0.335,0.942 respectively. These results suggested that clinical examination show only fair agreement, whereas radiologic examination show perfect agreement. Conclusion : The diagnositic performance of the dental periapical radiographs on interproximal caries were higher than that of clinical examination, thus this study showed the validity of periapical radiographs for detecting interproximal caries lesion without bitewing radiograph. (Korean J Oral Maxillofac Radiol 2000; 30: 49-54)

성공적인 임플란트시술을 위한 방사선검사

이삼선,최순철 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.2

Recently implant has become an important field in dental clinic. Radiographic examination of pre- and postoperation is essential for successful treatment. Clinicians should have knowledge about the purpose of the radiographic examination, suitable imaging modality for the cases, anatomic landmarks of tooth and jaw bone, advantage and limitation of panoramic radiographic examination for implant, principle and interpretation of crosssectional imaging, bone mineral density, post-operative radiographic examination. This paper will be helpful to get above informations for dentists who want to do dental implant successfully.

치과병원에서 사용되는 진단영상에 대한 JPEG 2000 압축률에 대한 평가

정기훈,한원정,유동수,최순철,김은경 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.3

Purpose : To find out the proper compression ratios without degrading image quality and affecting lesion detectability on diagnostic images used in dentistry compressed with JPEG 2000 algorithm. Materials and Methods : Sixty Digora periapical images, sixty panoramic computed radiographic (CR) images, sixty computed tomographic (CT) images, and sixty magnetic resonance (MR) images were compressed into JPEG 2000 with ratios of 10 levels from 5 : 1 to 50 : 1. To evaluate the lesion detectability, the images were graded with 5 levels (1: definitely absent; 2: probably absent; 3: equivocal; 4: probably present; 5: definitely present), and then receiver operating characteristic analysis was performed using the original image as a gold standard. Also to evaluate subjectively the image quality, the images were graded with 5 levels (1: definitely unacceptable; 2: probably unacceptable; 3: equivocal; 4: probably acceptable; 5: definitely acceptable), and then paired t-test was performed. Results : In Digora, CR panoramic and CT images, compressed images up to ratios of 15 : 1 showed nearly the same lesion detectability as original images, and in MR images, compressed images did up to ratios of 25 : 1. In Digora and CR panoramic images, compressed images up to ratios of 5 : 1 showed little difference between the original and reconstructed images in subjective assessment of image quality. In CT images, compressed images did up to ratios of 10 : 1 and in MR images up to ratios of 15 : 1. Conclusion : We considered compression ratios up to 5 : 1 in Digora and CR panoramic images, up to 10 : 1 in CT images, up to 15 : 1 in MR images as clinically applicable compression ratios.

치조 골소주 모폴로지 특성과 골다공증의 연관관계에 대한 연구

이창진,장훈상,이병도 대한구강악안면방사선학회 2005 Imaging Science in Dentistry Vol.35 No.3

Purpose : The purpose of this study was to investigate the preliminary use of morphologic operation (MO) in analyzing trabecular pattern of alveolar bone for the predicting systemic osteoporosis. Materials and Methods : Study subjects consisted of 35 females (average age 48.5 years) and 25 males (average age 25.8 years). Bone mineral density BMD (grams/cm²) of lumbar spine and proximal femur of these subjects were measured by a dual energy X-ray absorptiometry (DEXA). Regions of interest (ROIs) were selected from the digitized periapical radiographs of subjects’ posterior jaw. A custom computer program processed morphology operations of ROIs. We compared mean values of 11 MO variables according to the osteoporotic group divided by the T-scores of DEXA. We also studied correlation between radiographic density and these MO variables. Results : The mean radiographic densities insignificantly correlated with MO variables. There were statistically significant differences among the values of 9 MO variables according to the osteoporotic group. Conclusion : Morphologic operation can be effective in analyzing trabecular pattern of alveolar bone for the predicting osteoporosis.

Diagnostic ability of differential diagnosis in ameloblastoma and odontogenic keratocyst by imaging modalities and observers

Gang, Tae-In,Huh, Kyung-Hoe,Yi, Won-Jin,Heo, Min-Suk,Lee, Sam-Sun,Kim, Jeong-Hwa,Moon, Je-Woon,Choi, Soon-Chul 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.4

Purpose : To evaluate the diagnostic ability in differentiating between ameloblastoma and odontogenic keratocyst according to the imaging modalities and observers. Materials and Methods : We evaluated thirty-six cases of ameloblastomas and forty-seven cases of odontogenic keratocysts all histologically confirmed. Six oral and maxillofacial radiologists diagnosed the lesions by 3 methods: using panoramic radiograph, using computed tomograph (CT), and using panoramic radiograph and CT. The observers were classified by 3 groups: group 1 had experienced over 10 years in oral and maxillofacial radiologic field, group 2 had experienced for 3-4 years, and group 3 was in the process of residentship. After over 2 weeks, the observers diagnosed them by the same methods. Results : The ROC curve areas except for group 3 were the highest with interpretation using panoramic radiograph and CT, followed by interpretation using CT only, and the lowest with interpretation using panoramic radiograph only. The overall difference was not found in diagnostic ability among groups in using panoramic radiograph only, but there was difference in diagnostic ability of group 1 and 2 vs 3 in using CT only, and combination panoramic radiograph and CT. Conclusions : To differentiate between ameloblastoma and odontogenic keratocyst more accurately, the experienced oral and maxillofacial radiologist should diagnose with combination of panoramic radiograph and CT.

전산화단층영상에서 절치관 및 순측 치조골 폭경에 관한 연구

노양균,장현선,김병옥,김진수 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.3

Purpose : To assess the width of the labial alveolar bone of the incisive canal and the width of the incisive canal on spiral computed tomographic images of the anterior portion of the maxilla. Materials and Methods : Study materials included 38 CT scans taken for preoperative planning of implant placement. Axial cross-sectioned image entirely showing the incisive canal was selected and scanned with 600 DPI resolution. The width of the labial alveolar bone of the incisive canal at an orifice to the oral cavity, middle portion, and an orifice to the nasal cavity and the diameter of the incisive canal at the middle portion were determined by two specialist using Digora for Windows 2.1. The statistical analyses were carried out using SPSS 12.0.1. Results : When the maxillary central incisors remained, the mean labial alveolar bone width were 6.81±1.41 mm, 6.46±1.33 mm, and 7.91±1.33 mm. When the maxillary central incisors were missed the mean width were 5.42±2.20 mm, 6.23±29 mm, and 7.89±2.13 mm. Conclusions : The labial alveolar bone width at middle portion and an orifice to the nasal cavity were of no statistical significant difference according to presence of the maxillary central incisors (P>0.05). The width between oral cavity and nasal cavity, middle portion and to nasal cavity revealed statistically significant difference (P<0.05).

파노라마 및 경두개 방사선사진에서 하악과두의 조사각도

나경수 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.3

Purpose : To evaluate the true projection angles of film-side mandibular condyles in panoramic and transcranial radiographs. Materials and Methods : 52 panoramic and transcranial radiographs of 4 condyles from two human dry mandibles with gradual horizontal and vertical angle changes were taken. The results were compared with the standard panoramic and transcranial radiographs and the identical pairs were selected. Results and Conclusion : Panoramic radiography projected 10 degrees to the film-sided condyles both horizontally and vertically. Transcranial radiography projected 15 degrees to the film-sided condyles vertically. The medial and lateral poles were not forming the outline of condylar images in both projections when the horizontal angles of condyles were not sufficiently big enough.

Cone beam형 전산화 단층영상을 이용한 하악전치부 영양관의 연구

강정호,김규태,최용석,황의환 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.3

Purpose : To evaluate location, distribution, diameter, and length of the nutrient canals on mandibular anterior region using a cone beam computed tomography (CBCT). Materials and Methods : Mandibular CBCT was performed on 33 adults (18 males and 15 females) with no history of systemic disease, and any other dental surgery history. Location, distribution, diameter, and length of the nutrient canals on mandibular anterior region were radiographically evaluated. A statistical comparison was done by SPSS. Results : In the location and distribution of nutrient canals, they were found in 6.8% at labial portion above root apex, in 93.28% at lingual portion above root apex in 46.2% at labial portion below root apex, and in 53.6% at lingual portion below root apex. Nutrient canals at lingual portion above root apex were most frequently observed between central and lateral incisors, and those at labial and lingual portion below root apex were most frequently observed between central incisors. The mean diameters of nutrient canals were 0.54 mm at labial portion above root apex, 0.61 mm at lingual portion above root apex, 0.66 mm at labial portion below root apex, and 0.76 mm at lingual portion below root apex. The mean lengths of nutrient canals were 2.63 mm at labial portion above root apex, 3.74 mm at lingual portion above root apex, 4.51 mm at labial portion below root apex, and 6.77 mm at lingual portion below root apex. Conclusion : CBCT is useful device to evaluate the anatomical structure of nutrient canals on mandibular anterior region.

치과환자에서 경동맥 석회화 유발율에 대한 전산화단층사진 연구

윤숙자,이재서,윤웅 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.3

Purpose : Stroke is one of the leading causes of death in Korea. Atherosclerotic disease in the carotid artery bifurcation is the most common cause of stroke. The carotid artery calcification is easily appreciated by CT (Computed tomography). CT is often taken in a dental hospital for the diagnosis of inflammation, injury, cyst or tumor on maxillofacial region. However, there was no report of carotid artery calcification on CT in dental patients. This study was to determine the prevalence of carotid artery calcification on CT in dental patients. Materials and Methods : The presence of carotid artery calcification was evaluated by an experienced radiologist on CT scans of 287 patients (166 males, 121 females, average age 42, range 6 to 86 years) and the medical history of the patient and the interpretation of CT were reviewed. Results : Carotid artery calcification was detected on CT scans of 57 patients (19.8%; 35 males, 22 females). All the male patients with carotid artery calcification were older than 50, and all the female patients with carotid artery calcification were older than 60. Among the 57 patients, 10 had Diabetes mellitus, 20 had cardiovascular disease, 3 had history of stroke and 3 underwent radiation therapy for head and neck cancer. Carotid artery calcification was not included in the interpretation of CT of dental patients except one patient. Conclusion : The prevalence of carotid artery calcification on CT of dental patients was about 20% in this study. Carotid artery calcification should be included in the interpretation of CT of dental patients.