• Tuberculosis and Respiratory Diseases
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• v.55 no.3
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• pp.239-249
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• 2003

Multi-detector row CT (MDCT) provides faster speed, longer coverage in conjunction with thin slices, improved spatial resolution, and ability to produce high quality muliplanar and three-dimensional (3D) images. MDCT has revolutionized the non-invasive evaluation of the central airways. Simultaneous display of axial, multiplanar, and 3D images raises precision and accuracy of the radiologic diagnosis of central airway disease. This article introduces central airway imaging with MDCT emphasizing on the emerging role of multiplanar and 3D reconstruction.

• Imaging Science in Dentistry
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• v.39 no.1
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• pp.27-33
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• 2009

Purpose: The purpose of this study was to evaluate the clinical usefulness of the recently developed multi-detector computed tomography and cone beam computed tomography in pre-operative implant evaluation, by comparing them with the single detector computed tomography, already confirmed for accuracy in this area. Materials and Methods: Five partially edentulous dry human mandibles, with $1{\times}1mm$ gutta percha cones, placed in 5mm intervals posterior to the mental foramen on each side of the buccal part of the mandible, were used in this study. They were scanned as follows: 1) Single detector computed tomography: slice thickness 1mm, 200mA, 120kV 2) Multi-detector computed tomography: slice thickness 0.75mm, 250mA, 120kV 3) Cone beam computed tomography: 15mAs, 120kV Axial images acquired from three computed tomographies were transferred to personal computer, and then reformatted cross-sectional images were generated using V-Implant $2.0^{(R)}$ (CyberMed Inc., Seoul, Korea) software. Among the cross-sectional images of the gutta perch a cone, placed in the buccal body of the mandible, the most precise cross section was selected as the measuring point and the distance from the most superior border of the mandibular canal to the alveolar crest was measured and analyzed 10 times by a dentist. Results: There were no significant intraobserver differences in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). There were no significant differences among single detector computed tomography, multi-detector computed tomography and cone beam computed tomography in the distance from the most superior border of the mandibular canal to the alveolar crest (p>0.05). Conclusion: Multi-detector computed tomography and cone beam computed tomography are clinically useful in the evaluation of pre-operative site for mandibular dental implants, with consideration for radiation exposure dose and scanning time.

• Clinical and Experimental Pediatrics
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• v.54 no.5
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• pp.212-218
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• 2011

Purpose: The diagnosis of acute pyelonephritis (APN) is often difficult, as its clinical and biological manifestations are non-specific in children. If not treated quickly and adequately, however, APN may cause irreversible renal damage, possibly leading to hypertension and chronic renal failure. We were suspecting the diagnostic value of $^{99m}Tc$-dimercaptosuccinic acid (DMSA) scan by experiences and so compared the results of DMSA scan to those of multi-detector row computed tomography (MDCT). Methods: We retrospectively selected and analyzed 81 patients who were diagnosed as APN by MDCT during evaluation of their acute abdomen in emergency room and then received DMSA scan also for the diagnostic work-up of APN after admission. We evaluated the results of imaging studies and compared the diagnostic value of each method by age groups, <2 years (n=45) and ${\geq}$2 years (n=36). Results: Among total 81 patients with MDCT-proven APN, DMSA scan was diagnostic only in 55 children (68%), while the remaining 26 children (32%) showed false negative normal findings. These 26 patients were predominantly male and most of them, 19 (73.1%) were <2 years of age. Conclusion: DMSA scan holds obvious limitation compared to MDCT in depicting acute inflammatory lesions of kidney in children with APN, especially in early childhood less than 2 years of age. MDCT showed hidden lesions of APN, those were undetectable through DMSA scan in children.

• The Korean Journal of Pain
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• v.27 no.3
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• pp.266-270
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• 2014

Background: Knowledge of the anatomical variation of the vertebral artery has clinical importance not only for the performance of interventional or surgical procedures itself but also to ensure their safety. We conducted a study of the anatomical variation by reviewing multi-detector computed tomography (MDCT) images of the cervical spine from 460 Korean patients. Methods: 16-row MDCT data from 460 patients were used in this study. We observed 920 vertebral arteries. Examination points included level of entrance of the artery into the transverse foramen of the cervical vertebra, origin site of the vertebral artery, course of a vertebral artery with aberrant entrance. Result: The vertebral artery in 2 (0.2%) cases in this study entered into the transverse foramen of the 7th cervical vertebra from the left. In 45 (4.9%) cases, the vertebral artery entered into the transverse foramen of the 5th cervical vertebra. Of these, the entrance was on the right in 15 (1.6%) and on the left in 30 (3.3%). We found 17 (1.8%) cases in which the artery entered into the transverse foramen of the 4th cervical vertebra, 10 (1.1%) on the right and 7 (0.7%) on the left side. As is commonly acknowledged, the 6th cervical vertebra was the most common site of entry; the vertebral artery entered the transverse foramen of the 6th cervical vertebra in the remaining 855 (93.0%) cases, on the right in 434 (47.2%) and on the left in 421 (45.8%). Conclusions: In conclusion, the possibility of an atypical course of the vertebral artery in segments V1 and V2 should be evaluated with magnetic resonance imaging (MRI) or CT images before carrying out procedures involving the anterior cervical vertebrae.

• Journal of the Korean Society of Safety
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• v.28 no.1
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• pp.1-5
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• 2013

In this paper, the finite element analysis using ADINA has performed to investigate an accident that a man's head was damaged by the falling object. The simulation condition has defined by the point of forensic medicine view and the CCTV image analysis. From the CCTV image analysis, we expected that the sphere diameter of object is 15cm and object color is white. Assuming the falling mass is the ice mass, the results of the ADINA simulation show that a man's head can be broken by the falling ice mass.

• Archives of Plastic Surgery
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• v.38 no.6
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• pp.719-724
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• 2011

Purpose: Previous studies of the facial artery have shown significant anatomical variability in this region. The vascular anatomy of the region is considered unreliable in predicting the ideal pedicle. Preoperative imaging has been suggested as a means of improving preoperative awareness, with Doppler ultrasound as useful tools. Multi-detector row angiographic computed tomography (angio CT) is a significant improvement, providing noninvasive operator-independent details of the vascular anatomy. This tool was used to perform an $in$ $vivo$ anatomical study of the facial artery, demonstrating the usefulness of facial angio CT in planning the facial reconstruction. Methods: Eleven consecutive patients underwent facial angio CT of the facial vasculature with the anatomical details of the facial artery assessed. Results: Facial angio CT could demonstrate the size and course of the facial vasculature, particularly the facial artery. Conclusion: The vascular anatomy of the facial artery is highly variable, and thus there is a role for preoperative imaging. Facial angio CT can demonstrate cases where there is an aberrant or non-preferred anatomy, or select the method of a facial reconstruction.

• Journal of Chest Surgery
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• v.38 no.10 s.255
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• pp.710-713
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• 2005

Acute abdominal Aortic occlusion is rare but it is a vascular emergency with high mortality and morbidity. There­fore, delay in diagnosis can have severe impact on the prognosis. A 60-year-old women complained of paresthesia, paralysis, and severe pain in bilateral lower extremities on 13th day after open heart surgery for mitral stenosis, atrial fibrillation, coronary arterial stenosis, tricuspid regurgitation, and atrial septal defect. Her skin was mottled and cool from the umbilicus to the feet, and there were no palpable pulses in the lower exteremities. We diagnosed an acute abdominal aortic occlusion using the Multi-Detector Row Spiral Computed Tomography and successfully treated the problem with emergent thrombo-embolectomy and Aortobifemoral bypass.

• Journal of Radiation Protection and Research
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• v.32 no.3
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• pp.123-133
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• 2007

Z-axis automatic tube current modulation technique automatically adjusts tube current based on size of body region scanned. The purpose of the current study was to compare noise, and radiation dose of multi-detector row CT (MDCT) of lower extremity performed with Z-axis modulation technique of automatic tube current modulation with manual selection fixed tube current. Fifty consecutive underwent MDCT venography of lower extremity with use of a MDCT scanner fixed tube current and Z-axis automatic tube current modulation technique (10, 11 and 12 HU noise index, $70{\sim}450\;mA$). Scanning parameters included 120 kVp, 0.5 second gantry rotation time, 1.35:1 beam pitch, and 1 mm reconstructed section thickness. For each subject, images obtained with Z-axis modulation were compared with previous images obtained with fixed tube current (200, 250, 300 mA) and with other parameters identical. Images were compared for noise at five levels: iliac, femoral, popliteal, tibial, and peroneal vein of lower extremity. Tube current and gantry rotation time used for acquisitions at these levels were recorded. All CT examinations of study and control groups were diagnostically acceptable, though objective noise was significantly more with Z-axis automatic tube current modulation. Compared with fixed tube current, 2-axis modulation resulted in reduction of CTDIvol (range, $-6.5%{\sim}-35.6%$) and DLP (range, $-0.2%{\sim}-20.2%$). Compared with manually selected fixed tube current, 2-axis automatic tube current modulation resulted in reduced radiation dose at MDCT of lower extremity venography.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.71-81
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• 2008

Our objective was to evaluate the image of spatial domain filtering as an alternative to additional image reconstruction using different kernels in MDCT. Derived from thin collimated source images were generated using water phantom and abdomen B10(very smooth), B20(smooth), B30(medium smooth), B40 (medium), B50(medium sharp), B60(sharp), B70(very sharp) and B80(ultra sharp) kernels. MTF and spatial resolution measured with various convolution kernels. Quantitative CT attenuation coefficient and noise measurements provided comparable HU(Hounsfield) units in this respect. CT attenuation coefficient(mean HU) values in the water were values in the water were $1.1{\sim}1.8\;HU$, air($-998{\sim}-1000\;HU$) and noise in the water($5.4{\sim}44.8\;HU$), air($3.6{\sim}31.4\;HU$). In the abdominal fat a CT attenuation coefficient($-2.2{\sim}0.8\;HU$) and noise($10.1{\sim}82.4\;HU$) was measured. In the abdominal was CT attenuation coefficient($53.3{\sim}54.3\;HU$) and noise($10.4{\sim}70.7\;HU$) in the muscle and in the liver parenchyma of CT attenuation coefficient($60.4{\sim}62.2\;HU$) and noise ($7.6{\sim}63.8\;HU$) in the liver parenchyma. Image reconstructed with a convolution kernel led to an increase in noise, whereas the results for CT attenuation coefficient were comparable. Image scanned with a high convolution kernel(B80) led to an increase in noise, whereas the results for CT attenuation coefficient were comparable. Image medications of image sharpness and noise eliminate the need for reconstruction using different kernels in the future. Adjusting CT various kernels, which should be adjusted to take into account the kernels of the CT undergoing the examination, may control CT images increase the diagnostic accuracy.

• Progress in Medical Physics
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• v.26 no.1
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• pp.28-35
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• 2015

In this study, we investigated the effects of an iterative reconstruction algorithm and an automatic exposure control (AEC) technique on image quality and radiation dose through phantom experiments with coronary computed tomography (CT) angiography protocols. We scanned the AAPM CT performance phantom using 320 multi-detector-row CT. At the tube voltages of 80, 100, and 120 kVp, the scanning was repeated with two settings of the AEC technique, i.e., with the target standard deviations (SD) values of 33 (the higher tube current) and 44 (the lower tube current). The scanned projection data were reconstructed also in two ways, with the filtered back projection (FBP) and with the iterative reconstruction technique (AIDR-3D). The image quality was evaluated quantitatively with the noise standard deviation, modulation transfer function, and the contrast to noise ratio (CNR). More specifically, we analyzed the influences of selection of a tube voltage and a reconstruction algorithm on tube current modulation and consequently on radiation dose. Reduction of image noise by the iterative reconstruction algorithm compared with the FBP was revealed eminently, especially with the lower tube current protocols, i.e., it was decreased by 46% and 38%, when the AEC was established with the lower dose (the target SD=44) and the higher dose (the target SD=33), respectively. As a side effect of iterative reconstruction, the spatial resolution was decreased by a degree that could not mar the remarkable gains in terms of noise reduction. Consequently, if coronary CT angiogprahy is scanned and reconstructed using both the automatic exposure control and iterative reconstruction techniques, it is anticipated that, in comparison with a conventional acquisition method, image noise can be reduced significantly with slight decrease in spatial resolution, implying clinical advantages of radiation dose reduction, still being faithful to the ALARA principle.