• 대한치과의사협회지
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• 제48권10호
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• pp.724-728
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• 2010

Accurate analysis of facial asymmetry prior to any orthognathic or orthodontic treatment plan is essential in ensuring good treatment result. Dental CBCT (Cone-beam Computed Tomography) provides as actual three-dimensional measurements of distance and angle without any radiographic magnification as medical CT provides, while its field of view is limited to the oral and maxillofacial area. CBCT is a useful tool for the diagnosis of facial asymmetry. The coordinates of facial landmarks are obtained from the 3D reconstruction software which enables the establishment of perpendicular planes and the identification of the landmarks. Then, the bilateral discrepancies of the landmarks are obtained as spherical polar coordinates which can show the amount of asymmetry and its direction. A method of 3D analysis of facial asymmetry using CBCT is introduced in this report.

• 한국동물위생학회지
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• 제35권3호
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• pp.251-254
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• 2012

Pectus excavatum (PE) is a ventral chest wall deformity, also known as funnel chest, sunken chest, chondrosternal depression or koilosternia. The 4 months old, 1.3 kg intact-female Pekingese dog was evaluated for acute semicoma and convulsion. The client reported that this patient have had chronic loss of appetite, intermittent dyspnea and palpable sunken breast. The other littermates did not show any abnormalities. On physical examination, cachexia (BCS 1/5), concave sternum, flatten thoracic cavity and cardiac murmur were observed. On radiographic study, the caudal sternum cave to vertebrae and narrowing thoracic cavity. The severities of thoracic deformity were evaluated by deformation indices such as-Frontosagittal index (FSI) and vertebral index (VI). Moderate to severe PE was founded by the radiological measurements.

• Imaging Science in Dentistry
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• 제33권3호
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• pp.137-141
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• 2003

Purpose: To evaluate the precision of measurements taken of dental implants in bucco-lingually sectioned views of the maxilla by linear tomograms of the panorama and to assess the visibility of the inferior wall of the maxillary sinus. Materials and Methods : Eighty sites prepared with implants of gutta percha cone in the sockets of the upper premolars and molars of 10 dry skulls were radiographically examined using linear tomograms of panorama, and scanned coronally and axially by computed tomography. The differences in mm between the measurements in bucco-lingually sectioned images of maxillary alveolar bone and the true length and width of the implanted gutta percha cones were compared as mean values (mean) and standard deviations (SD) for each radiographic technique. Linear tomography of panorama was compared with computed tomography for visualization of the relationship between the inferior wall of maxillary sinus and the end of each implant. Results: The deviations between the actual implant length and the measured values taken from the linear tomograms (0.44±0.39 mm) was significantly less than the measured values from the multiplanar reconstructed images of the axially scanned computed tomogram (1.21 ± 0.90 mm). There was statistically significant difference (p < 0.05) between two techniques in the differences between the measurements and true implant length. The relationship of the inferior border of maxillary sinus with end of implant was worse identified with the linear tomogram of panorama (68%) than the multiplanar reconstructed image of axially scanned computed tomogram (99%). Conclusion: We could not find any differences in the accuracy of length measurement between the linear tomogram of panorama and computed tomogram, but computed tomogram allowed for a better visualization of the inferior wall of the maxillary sinus than the linear tomogram.

• Imaging Science in Dentistry
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• 제54권2호
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• pp.147-157
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• 2024

Purpose: The aim of this study was to explore the correlations of cone-beam computed tomographic findings with the apnea-hypopnea index in patients with obstructive sleep apnea. Materials and Methods: Forty patients with obstructive sleep apnea were selected from the ear-nose-throat (ENT) outpatient clinic, Faculty of Medicine, Mansoura University. Cone-beam computed tomography was performed for each patient at the end of both inspiration and expiration. Polysomnography was carried out, and the apnea-hypopnea index was obtained. Linear measurements, including cross-sectional area and the SNA and SNB angles, were obtained. Four oral and maxillofacial radiologists categorized pharyngeal and retropalatal airway morphology and calculated the airway length and volume. Continuous data were tested for normality using the Kolmogorov-Smirnov test and reported as the mean and standard deviation or as the median and range. Categorical data were presented as numbers and percentages, and the significance level was set at P<0.05. Results: The minimal value of the cross-sectional area, SNB angle, and airway morphology at the end of inspiration demonstrated a statistically significant association (P<0.05) with the apnea-hypopnea index, with excellent agreement. No statistically significant difference was found in the airway volume, other linear measurements, or retropalatal airway morphology. Conclusion: Cone-beam computed tomographic measurements in obstructive sleep apnea patients may be used as a supplement to a novel radiographic classification corresponding to the established clinical apnea-hypopnea index classification.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.150-160
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• 1996

The present study was to evaluate the accuracy of the frequency dependent type apex locator, Root-ZX. The subjects included 505 root canals of 238 teeth treated by the Department of Conservative Dentistry, and 22 human premolars which were schduled to be extracted for the orthodontic reasons. The results were as follows ; 1. The working lengths determined by Root-ZX were compared with radiographic readings. Of the total 505 root canals, 66 % showed coincidence within ${\pm}0.5mm$ and the average readings of Root-ZX were $0.13mm{\pm}1.05$ longer than those of radiographic readings. 2. The length difference between the file tip determined by Root-ZX and the apical constriction in extracted teeth were measured. Of the total 24 root canals, 70.8 % showed coincidence within ${\pm}0.5mm$ and the average readings of Root-ZX were $0.12mm{\pm}0.50$beyond the apical constriction. 3. The vitality of the teeth did not show any statistical difference(p>0.05) in the accuracy of the Root-ZX readings. The presence of the periapical lesions, however, significantly lowered the percentage of ${\pm}0.5mm$ accuracy in Root-ZX measurements.(p<0.05). In the presence of periapical lesions, the percentage within ${\pm}0.5mm$ was significantly lower.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권5호
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• pp.295-304
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• 2012

Objectives: Lateral cephalometry, computed tomography (CT) and full-night polysomnography were used to examine the correlation of obstructive sleep apnea (OSA) severity. Materials and Methods: A total of 29 patients (5 females, 24 males) diagnosed with OSA were evaluated by lateral cephalometry, CT and full-night polysomnography. Lateral cephalometry was performed in the closed and open mouth states. The radiographic and polysomnography measurements of the patients with OSA were evaluated statistically to determine the association with OSA severity. Results: A significant relationship was observed between the increased respiratory disturbance index and closing lateral cephalometry. With mouth opening, the airway space narrowed and the OSA worsened. Lateral cephalometry revealed OSA patients to have an inferiorly positioned hyoid bone, longer-than-normal soft palate and narrowing airway space. As OSA was severe, the airway shape was ovoid in the CT horizontal view. Conclusion: Polysomnography and the radiographic parameter can be used for diagnosing OSA.

• Clinics in Shoulder and Elbow
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• 제24권2호
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• pp.72-79
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• 2021

Background: A midshaft clavicle fracture is a common fracture that typically responds well to open reduction and internal fixation (ORIF). However, refracture can occur after implant removal (IR). This study aimed to analyze the rate of refracture and related factors after removal of the locking compression plate (LCP) for displaced midshaft clavicle fractures. Methods: We retrospectively reviewed the medical records of 201 patients who had undergone ORIF with LCP for midshaft clavicle fractures after IR after bony union from January 2011 to May 2018 at our institute. We evaluated basic demographic characteristics and radiographic parameters. All patients were treated with an LCP for primary fracture. The patients were divided into two groups: a refracture group that experienced a second fracture within 1 year after IR and a no-fracture group. Results: There were four cases (1.99%) of refracture; three were treated conservatively, while one was treated surgically. All patients achieved bony union. The average interval between refracture and IR was 64 days (range, 6-210 days). There was a significant difference in classification of fractures (AO Foundation/Orthopaedic Trauma Association [AO/OTA] classification) between the two groups. However, other patient demographics and radiographic measurements between refracture and IR, such as bone diameter, showed no significant difference between the two groups. Conclusions: This study showed that one in 50 patients suffered from refracture after removal of the LCP. Thus, if patients desire IR, the surgeon should explain that there is a relatively higher possibility of refracture for cases with simple or segmental fractures than for other types of fracture.

• Journal of Radiation Protection and Research
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• 제48권1호
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• pp.9-14
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• 2023

Background: The detectors of both computed radiography (CR) and direct digital radiography (DR) have a wide dynamic range that could tolerate high values of exposure factors without an adverse effect on image quality. Therefore, this study aims to assess patient radiation dose and proposes institutional diagnostic reference levels (DRLs) for two teaching hospitals in Ghana. Materials and Methods: CR and DR systems were utilized in this study from two teaching hospitals. The CR system was manufactured by Philips Medical Systems DMC GmbH, while the DR system was manufactured by General Electric. The entrance skin doses (ESDs) were calculated using the standard equation and the tube output measurements. Free-in-air kerma (µGy) was measured using a calibrated radiation dosimeter. The proposed institutional DRLs were estimated using 75^th percentiles values of the estimated ESDs for nine radiographic projections. Results and Discussion: The calculated DRLs were 0.4, 1.6, 3.4, 0.5, 0.4, 1.1, 1.0, 1.2, and 1.7 mGy for chest posteroanterior (PA), lumbar spine anteroposterior (AP), lumbar spine lateral (LAT), cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively in CR system. In the DR system, the values were 0.3, 1.6, 3.1, 0.4, 0.3, 0.7, 0.6, 0.9, and 1.3 for chest PA, lumbar spine AP, lumbar spine LAT, cervical spine AP, cervical spine LAT, skull PA, pelvis AP, and abdomen AP, respectively. Conclusion: Institutional DRLs in nine radiographic projections have been proposed for two teaching hospitals in Ghana for the first time. The proposed DRLs will serve as baseline data for establishing local DRLs in the hospitals and will be a valuable tool in optimizing patient doses.

• 한국임상수의학회지
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• 제40권1호
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• pp.31-37
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• 2023

Vertebral left atrial size (VLAS) is an important indicator to predict myxomatous mitral valve degeneration (MMVD) in dogs. When the caudal margin of cardiac silhouette and the dorsal margin of caudal vena cava (CdVC) could not be seen exactly, another way to evaluate VLAS is needed. The objective of this study was to assess whether a new modified VLAS (m-VLAS) could be used as an indicator to predict MMVD in 57 small breed dogs with MMVD. The m-VLAS was also used to classify American College of Veterinary Internal Medicine staging groups and left heart enlargement confirmed with echocardiograph (EchoLHE) groups. The m-VLAS was measured as the distance from the ventral aspect of the carina to the dorsal aspect of the intersection of the cardiac silhouette and the farthest LA caudal margin, not the CdVC, followed by drawing the same line beginning at the cranial edge of T4. Based on VLAS values and m-VLAS values measured for dogs with MMVD, correlations between these values and left heart enlargement groups were then evaluated. There were significant differences in both the VLAS and the m-VLAS between EchoLHE groups. The AUC of the ROC curve of the m-VLAS to detect EchoLHE was higher than that of the VLAS. The optimal cutoff value for the m-VLAS was >2.7, which had a higher specificity (86.84%) than the VLAS specificity (71.05%). This study reveals that a new m-VLAS is a more specific indicator than the VLAS for predicting left side heart enlargement in small breed dogs. Therefore, the m-VLAS can be used as a clinically useful radiographic measurement alternative to or better than the VLAS.

• 대한치과교정학회지
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• 제28권1호
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• pp.75-83
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• 1998

본 연구는 교정 치료를 위한 진단과 치료 계획의 수립에 널리 이용되는 진단 수단의 하나인 두부 방사선 사진을 계측하는 연구에서 볼 수 있는 오류의 중요성을 인식하고, 반복 계측의 방법으로 체계적 오차(systematic error)를 찾아내고 임의적오차(random error)의 범위를 산출하는 과정을 통해 기준점의 식별에 보다 주의가 기울여져야 할 해부학적 기준점들을 찾아보고자 시행되었는데, 통법에 의해 촬영된 100장의 측모 두부 방사선 사진을 연구대상으로 하여 61개의 기준점과 130개의 계측항목을 선정하였고 반복계측을 위해 25개의 표본을 무작위로 선정, 계측오차를 분석하여 다음과 같은 결론을 얻었다. 1. 반복계측에 따른 계측치의 비교에서 130개 전체 계측항목의 18.4%인 24개 항목에서 유의성 있는 차이를 보였다. 2. 반복계측에서 기준점 식별에 차이를 보이는 빈도는 상악 전치의 치근단점(as), 상악골의 최후방벽(tu), 연조직 nasion과 전두정(ft) 그리고 기도의 ad3점에서 매우 높았다. 3. 5%이하의 유의도를 보이는 수준까지 기준점 마킹을 수정한 후, 임의적오차의 범위는 0.67-1.71mm또는 도를 보였다. 4. 가장 임의적오차를 보인 계측항목은 상, 하악 전치가 이루는 각(interincisal angle : ILs-ILi)이었다. 5. 계측 오차의 문제는 주로 해부학적 정의에 대한 정확성의 부족과 불분명한 방사선사진상에 기인되었다. 이상의 연구 결과로 두부 방사선 사진의 계측에는 많은 오류의 가능성이 있음을 확인할 수 있었고 이에 따라 두부방사선 계측에서 뿐 아니라 계측이 이루어지는 모든 연구에서는 항상 계측오류에 대한 분석이 함께 이루어져야 할 것이며, 조사자로서 뿐만 아니라 다른 연구자의 연구결과를 올바르게 인식하기 위한 목적으로도 오류에 대한 인식은 필수적인 것으로 생각된다.