• Imaging Science in Dentistry
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• 제48권1호
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• pp.51-57
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• 2018

Purpose: To perform a comparative analysis of the palatal bone thickness in Thai patients exhibiting class I malocclusion according to whether they exhibited a normal or open vertical skeletal configuration using cone-beam computed tomography (CBCT). Materials and Methods: Thirty CBCT images of Thai orthodontic patients (15-30 years of age) exhibiting class I malocclusion with a normal or open vertical skeletal configuration were selected. Palatal bone thickness was measured in a 3.0-mm grid pattern on both the right and left sides. The palatal bone thickness of the normal-bite and open-bite groups was compared using the independent t-test. The level of significance was established at P<.05. Results: The palatal bone thickness in the normal-bite group ranged from $2.2{\pm}1.0mm$ to $12.6{\pm}4.1mm$. The palatal bone thickness in the open-bite group ranged from $1.9{\pm}1.1mm$ to $13.2{\pm}2.3mm$. The palatal bone thickness was lower at almost all sites in patients with open bite than in those with normal bite. Significant differences were found at almost all anteroposterior sites along the 3 most medial sections (3.0, 6.0, and 9.0 mm lateral to the midsagittal plane)(P<.05). Conclusion: Class I malocclusion with open vertical skeletal configuration may affect palatal bone thickness, so the placement of temporary anchorage devices or miniscrew implants in the palatal area in such patients should be performed with caution.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.17-25
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• 2021

Purpose: This study was performed to investigate mandibular canal displacement in patients with ameloblastoma using a 3-dimensional mirrored-model analysis. Materials and Methods: The sample consisted of computed tomographic scans of patients with ameloblastoma (n=10) and healthy controls (n=20). The amount of mandibular canal asymmetry was recorded as a continuous variable, while the buccolingual (yaw) and supero-inferior (pitch) directions of displacement were classified as categorical variables. The t-test for independent samples and the Fisher exact test were used to compare groups in terms of differences between sides and the presence of asymmetric inclinations, respectively (P<0.05). Results: The length of the mandibular canal was similar on both sides in both groups. The ameloblastoma group presented more lateral (2.40±4.16 mm) and inferior (-1.97±1.92 mm) positions of the mental foramen, and a more buccal (1.09±2.75 mm) position of the middle canal point on the lesion side. Displacement of the mandibular canal tended to be found in the anterior region in patients with ameloblastoma, occurring toward the buccal and inferior directions in 60% and 70% of ameloblastoma patients, respectively. Conclusion: Mandibular canal displacement due to ameloblastoma could be detected by this superimposed mirrored method, and displacement was more prevalent toward the inferior and buccal directions. This displacement affected the mental foramen position, but did not lead to a change in the length of the mandibular canal. The control group presented no mandibular canal displacement.

• Imaging Science in Dentistry
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• 제51권1호
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• pp.35-40
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• 2021

Purpose: This study was conducted to evaluate the accuracy of cone-beam computed tomography (CBCT) in detecting the posterior superior alveolar(PSA) artery canal in a sample of the Egyptian population. Materials and Methods: CBCT images of 600 maxillary sinuses of patients were examined for the presence or absence of the PSA artery along the lateral wall of the maxillary sinus, and for the diameter and type of the canal in relation to age and sex. The distances from the canal to the alveolar crest and sinus floor were also measured. Each canal was assessed to determine whether it was bifid. Results: The PSA artery canal could be detected in 92.0% of the sinuses. The mean distance from the inferior border of the PSA artery canal to the sinus floor was 8.2±2.2 mm (range, 3.2-13.6 mm) in males and 7.3±2.1 mm (range, 3.0-13.1 mm) in females. The mean distance from the inferior border of the PSA artery canal to the alveolar crest was 18.2±2.7 mm (range, 11.0-23.9 mm) in males and 17.4±2.3 mm (range, 10.8-23.5 mm) in females. The mean diameter of the PSA artery canal was larger in male subjects. The PSA artery canal was bifid in 8.7% of cases. The most frequently observed location of the PSA artery canal was intraosseous(82.2%). Conclusion: CBCT was confirmed to be a valuable tool for evaluation and localization of the PSA artery before maxillary sinus lift surgery to avoid intraoperative bleeding.

• Imaging Science in Dentistry
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• 제53권2호
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• pp.153-159
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• 2023

Purpose: The objective of this study was to assess the fractal dimension, lacunarity, trabecular microarchitecture parameters, and cortical linear measurements in the mandibles of male and female individuals to identify differences between them. Materials and Methods: In total, 116 cone-beam computed tomography scans of healthy individuals of different ages (57 men and 59 women, aged between 20 and 60 years) were selected. The following bone parameters were measured: 1) buccal, lingual, and basal cortical bone thickness in 5 standard parasagittal sections (the midline, the left and right sides of the lower lateral incisors, and the left and right sides of the lower canines); 2) the bone volume fraction of 10 sequential axial sections from each patient by creating a volume of interest in the area between the lower canines; and 3) fractal dimension and lacunarity using grayscale images of the same region of the volume of interest in the anterior mandible. Spearman correlation coefficients and the Mann-Whitney test were used. Results: A significant and positive correlation was found between age and cortical thickness, especially in the region of the central incisors. Significant differences between sexes in terms of fractal dimension, lacunarity, and bone volume were found. Women revealed lower fractal dimension values and higher lacunarity and bone volume ratio values than men. Conclusion: Fractal dimension, lacunarity, trabecular bone volume, and cortical thickness were different between men and women of different ages.

• Journal of Korean Neurosurgical Society
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• 제63권2호
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• pp.237-247
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• 2020

Objective : Fixation of the C1-2 segment is challenging because of the complex anatomy in the region and the need for a high degree of accuracy to avoid complications. Preoperative 3D-computed tomography (CT) scans can help reduce the risk of complications in the vertebral artery, spinal cord, and nerve roots. However, the patient may be susceptible to injury if the patient's anatomy does not match the preoperative CT scans. The intraoperative 3D image-based navigation systems have reduced complications in instrument-assisted techniques due to greater accuracy. This study aimed to compare the radiologic outcomes of C1-2 fusion surgery between intraoperative CT image-guided operation and fluoroscopy-guided operation. Methods : We retrospectively reviewed the radiologic images of 34 patients who underwent C1-2 fusion spine surgery from January 2009 to November 2018 at our hospital. We assessed 17 cases each of degenerative cervical disease and trauma in a study population of 18 males and 16 females. The mean age was 54.8 years. A total of 139 screws were used and the surgical procedures included 68 screws in the C1 lateral mass, 58 screws in C2 pedicle, nine screws in C2 lamina and C2 pars screws, four lateral mass screws in sub-axial level. Of the 34 patients, 19 patients underwent screw insertion using intraoperative mobile CT. Other patients underwent atlantoaxial fusion with a standard fluoroscopy-guided device. Results : A total of 139 screws were correctly positioned. We analyzed the positions of 135 screws except for the four screws that performed the lateral mass screws in C3 vertebra. Minor screw penetration was observed in seven cases (5.2%), and major pedicle screw penetration was observed in three cases (2.2%). In one case, the malposition of a C2 pedicle screw was confirmed, which was subsequently corrected. There were no complications regarding vertebral artery injury or onset of new neurologic deficits. The screw malposition rate was lower (5.3%) in patients who underwent intraoperative CT-based navigation than that for fluoroscopy-guided cases (10.2%). And we confirmed that the operation time can be significantly reduced by surgery using intraoperative O-arm device. Conclusion : Spinal navigation using intraoperative cone-beam CT scans is reliable for posterior fixation in unstable C1-2 pathologies and can be reduced the operative time.

• 치과방사선
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• 제29권1호
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• pp.309-325
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• 1999

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/sup (R)/. 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 0.3 mm 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 0.7 mm there was statistically significant difference between the 15° control angle and the altered tomographic angles (p<0.05). In 1.0 mm 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 0.3 mm and 2.0 mm there was no significant difference between the 15° control angle and all the altered angles (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° altered angle there was significant difference (p<0.05). Conclusion: When imaging the lateral tomography of the temporomandibular joint used by SCANORA/sup (R)/, it can be considered that in the osteophytic lesion size of 2 mm 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 1 mm, the altered angle within ±10° also has little effect on the lesion detectability.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권3호
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• pp.267-275
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• 2005

Obstructive sleep apnea syndrome (OSAS) is characterized by sleep-induced obstruction of the upper airway that results in cessation of airflow. Obstruction can occur at a number of points in the airway, but frequently in the oropharynx. A diagnostic evaluation includes cephalometry, computed tomography, magnetic resonance imaging, acoustic reflection technique, polysomnography and fibroptic endoscopy. Cephalometric measurements of the patients with obstructive sleep apnea have revealed that posterior airway anatomy has strong relations with the symptoms of them. A lateral cephalogram is routinely obtained in the radiologic evaluation of sleep apnea patients. The purpose of this study is to provide a the lateral cephalometric korean norms for the diagnosis and treatment of the patients with obstructive sleep apnea by analyzing the abnormal occlusion of Korean adults.

• 한국의학물리학회지:의학물리
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• 제28권4호
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• pp.144-148
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• 2017

When a high density metallic implant is placed in the path of the proton beam, spatial heterogeneity can be caused due to artifacts in three dimensional (3D) computed tomography (CT) scans. These artifacts result in range uncertainty in dose calculation in treatment planning system (TPS). And this uncertainty may cause significant underdosing to the target volume or overdosing to normal tissue beyond the target. In clinical cases, metal implants must be placed in the beam path in order to preserve organ at risk (OARs) and increase target coverage for tumors. So we should introduce Ti-mesh. In this paper, we measured the lateral dose profile for proton beam using an EBT3 film to confirm dosimetric impact of Ti-mesh when the Ti-mesh plate was placed in the proton beam pathway. The effect of Ti-mesh on the proton beam was investigated by comparing the lateral dose profile calculated from TPS with the film-measured value under the same conditions.

• Journal of Oral Medicine and Pain
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• 제37권4호
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• pp.227-231
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• 2012

국한성 화골성 근염은 근육내에 섬유조직과 이소성 골이 형성되는 질환으로 외상성 화골성 근염으로도 알려져 있으며 외상, 외과적 술식, 지속적인 자극에 의하여 근육이 골화되는 질환이다. 주로 팔, 다리 근육에서 발생되며, 저작근에서 발생되는 예는 드물다. 저작근에 발생된 경우 주된 임상증상은 개구제한이며 환자는 이환부위의 동통이나 불편함을 호소하기도 한다. 본 연구는 30대 남성이 개구제한을 주소로 내원하여 임상검사와 방사선검사 후 저작근중에서 좌측 측두근과 외측 익돌근에서 발생된 국한성 화골성 근염으로 진단 내려진 증례를 보고하고자 한다.

• Journal of Trauma and Injury
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• 제26권3호
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• pp.252-254
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• 2013

A hepatic hemangioma is the most frequent benign liver tumor. Once rupture occurs, the bleeding can barely be controlled by using conservative management or endovascular treatment. We report a case of traumatic hepatic hemangioma rupture. A 60-year-old man was referred to our hospital under cardiopulmonary cerebral resuscitation (CPCR). CPCR was continued for 16 minutes after his admission to the emergency room (ER). Computed tomography (CT) showed fluid accumulation in the peritoneal cavity with active contrast extravasation in the left lateral segment of the liver. Percutaneous transarterial embolization and massive transfusion were carried out. Embolization did not stop the bleeding, we decided on an exploration and then resected the lateral segment of the liver to control the bleeding. The specimen showed a ruptured hemangioma in the liver segment.