• The Journal of Korea Assosiation for Disability and Oral Health
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• v.4 no.1
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• pp.21-25
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• 2008

A 33-years-old female pateint with cerebral palsy showing spastic quardriplegia and severe mental retardation was scheduled for dental implant restorations. Before implant surgery we had to take implant CT. But, because of her involuntary motion and communication difficulty, sedation was needed in order to take CT. After 8 hour NPO, propofol infusion sedation with TCI (target controlled infusion) system was administered. The propofol blood concentration of the patient was maintained 2-3 ${\mu}$/ml to keep deep sedation to prevent uncontolled movement. During sedation, we monitored ECG, pulse oximetry, blood pressure, capnometry for patient safety. Oxygen was administered via nasal prong for preventing hypoxemia and to keep airway during sedation some bands were applied to lift mandible. Total duration was 20 minutes for taking CT, and she was discharged from hospital after 30 minute rest without complication.

• Tuberculosis and Respiratory Diseases
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• v.65 no.4
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• pp.339-342
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• 2008

Early CT findings of transient radiographic progression (TRP) during treatment of active pulmonary tuberculosis including subpleural, interlobular or intralobular septal thickening and micronodules are shown in the present case. Late CT findings of TRP are subpleural, enhancing nodular infiltration with internal low attenuation. These CT features accompanied by a lack of clinical worsening in young patients taking antituberculous medication due to pulmonary tuberculosis can help to differentiate TRP from other disease entities.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.40
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• pp.17.1-17.7
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• 2018

Background: Bisphosphonate (BP) has the ability to thicken the cortical bone. In addition, it has been reported that the cortical bone thickened by BP has relation to the medication-related osteonecrosis of the jaw (MRONJ). Therefore, the objective of this article is to analyze the ratio as well as thickness of cortical bone in the mandible using computed tomography (CT) and to evaluate it as the predictive factor of MRONJ. Methods: The thickness of the cortical bone was measured on a paraxial view of the CT showing the mental foramen in 95 patients: 33 patients with MRONJ (3 males, 30 females), 30 patients taking BP without MRONJ (2 males, 28 females), and 32 controls (9 males, 28 females). Also, the ratios of the cortical bone to the total bone were obtained using the measured values. Based on these results, we compared the difference of mandibular cortical bone ratio between the three groups. Results: The average cortical bone thickness was measured as 3.81 mm in patients with MRONJ, 3.39 mm in patients taking BP without MRONJ, and 3.23 mm in controls. There was only a significant difference between patients with MRONJ and controls (P < 0.05). On the other hand, the average mandibular cortical bone ratio was measured as 37.9% in patients with MRONJ, 27.9% in patients taking BP without MRONJ, and 23.3% in controls. There was a significant difference between all groups (P < 0.05). Conclusion: The mandibular cortical bone ratio is large in order of patients with MRONJ, patients taking BP without MRONJ, and controls. This result suggests that the mandibular cortical bone ratio would be very useful to predict the development of MRONJ.

• Journal of radiological science and technology
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• v.41 no.2
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• pp.103-107
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• 2018

In MR, the iodine CT contrast medium reduces the T1 and T2 relaxation times of the substance, resulting in a change in signal intensity. This study aimed to measure the relaxation rate of MR contrast medium with or without diluting CT contrast medium and analyzed the effect of CT contrast medium. Undiluted Gadoteridol solution was diluted with saline to prepare MR contrast medium phantoms with various levels of Gadoteridol concentrations. Moreover, undiluted Iomeprol was mixed with the prepared MR contrast medium phantoms at 1:1 ratio to make MR contrast medium phantoms with containing CT contrast medium for the experiment. T1 and T2 mappings were conducted to quantitatively evaluate the relaxation time and relaxation rate of these phantoms. The results showed that the T1 and T2 relaxation time and relaxation rate of MR contrast medium diluted with CT contrast medium were significantly (p<0.05) shorter than those of MR contrast medium not diluted with CT contrast medium. The results of this study imply that, when MR contrast medium shall be used after injecting CT contrast medium, CT contrast medium should be discharged enough. Moreover, it would be desirable to conduct CT test after taking MRI test in order to reduce the effects of CT contrast medium on MR contrast medium.

• KIPS Transactions on Computer and Communication Systems
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• v.12 no.1
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• pp.41-46
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• 2023

Iterative reconstruction of CT takes a long time because projection and back-projection are alternatively repeated until taking a good image. To reduce the reconstruction time, we need a fast algorithm for calculating the projection which is a time-consuming step. In this paper, we proposed a new algorithm to calculate the line integral and the algorithm is approximately 10% faster than the well-known Siddon method (Jacobs version) and has a good image quality. Although the algorithm has been investigated for the case of parallel beams, it can be extended to the case of fan and cone beam geometries in the future.

• Archives of Plastic Surgery
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• v.34 no.5
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• pp.605-610
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• 2007

Purpose: Facial trauma is increasing along with increasing popularity in sports, and increasing exposure to crimes or traffic accidents. Compared to the 3D CT of 1990s, the latest CT has made significant improvement thus resulting in higher accuracy of diagnosis. The objective of this study is to compare 64 channel 3 dimensional volume CT(3D VCT) with conventional 3D CT in the diagnosis and treatment of facial bone fractures. Methods: 45 patients with facial trauma were examined by 3D VCT from Jan. 2006 to Feb. 2007. 64 channel 3D VCT which consists of 64 detectors produce axial images of 0.625 mm slice and it scans 175 mm per second. These images are transformed into 3 dimensional image using software Rapidia 2.8. The axial image is reconstructed into 3 dimensional image by volume rendering method. The image is also reconstructed into coronal or sagittal image by multiplanar reformatting method. Results: Contrasting to the previous 3D CT which formulates 3D images by taking axial images of 1-2 mm, 64 channel 3D VCT takes 0.625 mm thin axial images to obtain full images without definite step ladder appearance. 64 channel 3D VCT is effective in diagnosis of thin linear bone fracture, depth and degree of fracture deviation. Conclusion: In its expense and speed, 3D VCT is superior to conventional 3D CT. Owing to its ability to reconstruct full images regardless of the direction using 2 times higher resolution power and 4 times higher speed of the previous 3D CT, 3D VCT allows for accurate evaluation of the exact site and deviation of fine fractures.

• Korean Journal of Digital Imaging in Medicine
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• v.15 no.1
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• pp.55-59
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• 2013

Patients who had claustrophobia tend to feel fear when they were scanned by an MRI, CT, PET-CT, or using a gamma camera scan. In this paper, claustrophobic patients were tested to find effective ways by changing patient's positions. For this paper, PET-CT scan in patients who had claustrophobia were used in the prone position. Prone position helped to maintain stable position and to get a h0igh quality of inspection without failure. Thus, as claustrophobic patients were requested taking prone position, they could feel comfortable. In a confined space, prone position for the claustrophobic patients who had a fear of the PET-CT examination would be expected to reduce the failure rate of inspection.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.3
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• pp.227-236
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• 1992

In this paper, a simulation program of relaying system including the CT and CPD ( capacitive potential device ) is developed to study the effect of its operation under various system conditions. To deal with the dynamic characteristics of relaying system, state space technique is applied, and then the state equations of CT, CPD and mho distance relay are constructed. Also the dynamic response characteristics of overall relaying system is verified by digital simulation. Since the proposed model is capable of taking arbitrary input waveforms from EMTP in analyzing its dynamic responses, the effects of CT-saturation and CPD-subsidence transient characteristics on the operating points of who distance relay can be accurately prodicted. It gives more effective results, compared with the model without considering those characteristics by checking the exprimental data.

• Nuclear Medicine and Molecular Imaging
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• v.42 no.1
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• pp.70-73
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• 2008

A 65 year-old man with hepatocellulcar carcinoma (HCC) admitted to treat left lower leg swelling and pus discharge suspecting osteomyelitis. MRI of his lower leg revealed the bone metastasis. Whole body FDG PET/CT additionally detected left shoulder and right ilium metastasis. Hematemesis suddenly developed in this patient after 3 weeks. Metastasis of right tonsil was histologically proven. When we reviewed his FDG PET/CT, there was asymmetric mild hypermetabolism in the right tonsil. When focal hypermetabolism is shown in the organ physiologically taking glucose up such as tonsil, we should cautiously assess whole body PET/CT in the examination of distant metastasis. We present a patient with multiple distant metastasis including tonsil from HCC showing increased FDG uptake with the literature review.

• Journal of Dental Rehabilitation and Applied Science
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• v.27 no.2
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• pp.175-184
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• 2011

With a development of implant restoration technique, there are increasing use of computer-guided system for edentulous patients. It was carried out simulated operation based on CT information about patient's bone quantity, quality and anatomical landmark. However, there are some difference between the programmed implant and post-operative implant about it's position. If the deviation was severe, it could happen a failure of 'passive fit' and not suited for path of implant restoration. The aim of this presentation is to evaluate about a degree of deviations between programmed implant and post-operative implant. Five patients treated by 'NobelGuide' system (Nobel Biocare AB, G$\ddot{o}$teborg, Sweden) in Department of Prosthodontics, Inha University were included in this study. The patients were performed CT radiograph taking and intra-oral impression taking at pre-operation. Based on CT images and study model, surgical stent was produced by NobelBiocareTM. To fabricated a pre-operative study model, after connected lab analog to surgical template, accomplished a pre-operative model using type 4 dental stone. At final impression, a post-operative study model was fabricated in the conventional procedures. Each study model was performed CT radiograph taking. Based on CT images, each implant was simulated in three dimensional position using $Procera^{(R)}$ software (Procera Software Clinical Design Premium, version 1.5; Nobel Biocare AB). In 3D simulated model, length and angulation between each implant of both pre- and post-operative implants were measured and recorded about linear and angular deviation between pre-and post-operative implants. A total of 24 implants were included in this study and 58 inter-implant sites between each implant were measured about linear and angular deviations. In the linear deviation a mean deviation of 0.41 mm (range 0~1.7 mm) was reported. In the angular deviation, a mean deviation was $1.99^{\circ}$ (range $0^{\circ}{\sim}6.7^{\circ}$). It appears that the both linear and angular mean deviation value were well acceptable to application of computer-guided implant system.