1.MTF Evaluation and Clinical Application according to the Characteristic Kernels in the Computed Tomography.
Beong Gyu YOO ; Dae Cheol KWEON ; Jong Seok LEE
Korean Journal of Medical Physics 2007;18(2):55-64
Our objective was to evaluate the clinical feasibility of spatial domain filtering as an alternative to additional image reconstruction using different kernels in CT. Kernels were grouped as H30 (head medium smooth), B30 (body medium smooth), S80 (special) and U95 (ultra sharp). Derived from thin collimated source images, four sets of images were generated using phantom kernels. MTF (50%, 10%, 2%) measured with H30 (3.25, 5.68, 7.45 lp/cm), B30 (3.84, 6.25, 7.72 lp/cm), S80 (4.69, 9.49, 12.34 lp/cm), and U95 (14.19, 20.31, 24.67 lp/cm). Spatial resolution for the U95 kernel (0.6 mm) was 33.3% greater than that of the H30 and B30 (0.8 mm) kernels. Initially scanned kernels images were rated for subjective image quality, using a five-point scale. Image scanned with a convolution kernel led to an increase in noise (U95), whereas the results for CT attenuation coefficient were comparable. CT images increase the diagnostic accuracy in head (H30), abdomen (B30), temporal bone and lung (U95) kernels may be controlled by adjusting CT various algorithms, which should be adjusted to take into account the kernels of the CT undergoing the examination.
Abdomen
;
Head
;
Image Processing, Computer-Assisted
;
Lung
;
Noise
;
Temporal Bone
2.Clinical Application of Acute Ischemic Stroke in Perfusion Computed Tomography.
Jong Seok LEE ; Dae Cheol KWEON ; Beong Gyu YOO
Korean Journal of Medical Physics 2007;18(3):149-160
Recent advent of 64-multidetctor (MD) CT enables more coverage of Z-axis in the perfusion imaging. The purpose of this study was to evaluate the clinical usefulness of perfusion CT by using 64-MD CT in detecting the lesion in patients with acute stroke. The perfusion CT was performed by using 64-MD CT in 62 consecutive patients who were initially suspected to have subacute ischemic stroke symptoms during the period of recent 9 months. These patients had subacute stroke (n=62). CT scanning was conducted with Jog Mode which provided 16 imaging slices with 5 mm of slice thickness, and 8 cm of coverage in Z-axis. Scan interval was 1 seconds for each imaging slice and total 15 scans were repeated. After CT scanning, perfusion maps (CBV, CBF, MTT and TTP) were created at Extended Brilliance Workstation. The CBV and CBF maps showed that lesions were smaller images. While on the MTT and TTP map lesions were seen to be larger fifty-one were large than they appeared on these images. Two slices of perfusion maps obtained at the level of the basal ganglia were chosen to simulate conventional older perfusion CT with 8 cm of coverage in Z-axis. TTP and MTT maps may be clinically useful for evaluation of the penumbral zone in cases of aubacute cerebral ischemic stroke. The perfusion CT is useful in the assessment of acute stroke as an initial imaging modality.
Basal Ganglia
;
Humans
;
Perfusion Imaging
;
Perfusion*
;
Stroke*
;
Tomography, X-Ray Computed
3.Measurement of Femoral Anteversion in the PACS Image Viewer.
Journal of Korean Society of Medical Informatics 2001;7(4):41-47
The measurement of the femoral anteversion is an important factor in the practice of orthopedic surgery. The anteversion is measured by means of the axis of head and neck of the femur. In this study, widely used computed tomography method of measuring anteversion was tested on femoral necks of patients. Measurement by the manual method and image viewer of computed tomography to determine the anteversion of femoral head were carried out on both femurs. In January and February 2001, 30 patients 3 to 6 years of age were randomly selected from Seoul National University Hospital. The purpose of this paper was to introduce a new method to measure femoral anteversion angle utilizing image viewer program. This new method was more accurate and convenient than the conventional manual method. In conclusion, PACS of image viewer program was statistically more reliable in determining the angle of the femoral anteversion.
Axis, Cervical Vertebra
;
Femur
;
Femur Neck
;
Head
;
Humans
;
Neck
;
Orthopedics
;
Seoul
4.Comparative Study in the Femoral Anteversion measured by CT and MR Imaging as a PACS Image Viewer.
Dae Cheol KWEON ; Sung Gwan YANG ; Peom PARK
Journal of Korean Society of Medical Informatics 2002;8(4):21-27
CT and MR have been used successfully to estimate the femoral anteversion angle. It is measured by means of the axis of head and neck of the femur and the knee axis. At the present time, widely used computed tomography method of measuring anteversion on femoral necks of patients. In this study, femoral anteversion angles in 36 years old human adult femur was determined by CT and MR imaging and the measurements compared. Measurement by the manual method and image viewer of computed tomography to determine the anteversion of femoral head were carried out on both femurs. On CT, the mean angle for adults was 20.1degrees. On MR imaging, the mean angle for adults was 20.4degrees. The correlation coefficient between angles determined by CT and MRI scan(r=.80). The femoral anteversion angles by MR imaging exceeded those obtained by CT. No significant difference was observed between the CT and MR imaging. MR imaging is recommended for prospective planning very usefulness in the measured the angle of the femoral anteversion.
Adult
;
Axis, Cervical Vertebra
;
Femur
;
Femur Neck
;
Head
;
Humans
;
Knee
;
Magnetic Resonance Imaging*
;
Neck
5.Comparison of F-18 FDG Radioacitivity to Determine Accurate Dose Calibrator Activity Measurements.
Gye Hwan JIN ; Dae Cheol KWEON ; Ki Baek OH ; Hoon Hee PARK ; Jung Yul KIM ; Min Soo PARK ; Dae Sung PARK
Korean Journal of Medical Physics 2009;20(3):159-166
Obviously, the administration of the prescribed amount of activity to the patient requires proper operation of the dose calibrator, which shall be verified by implementing the required quality control on the instrument. This investigation examined the accuracy and precision of dose calibrator activity measurement of the radiopharmaceutical F-18 FDG. To investigate the status of the nuclear medicine centers in Korea for the performance of dose calibrators, 10 centers providing PET/CT system services in Korea were inspected in 2008. We measured accuracy and precision in 10 equipments in consideration of PET/CT model, installation area, and installation time. According to the results of comparative analysis of 10 dose calibrators used to measure radioactivity of F-18 FDG, accuracy was -5.00~4.50% and precision was 0.05~0.45%, satisfying the international standards, which are accuracy +/-10% and precision +/-5%. This study demonstrated that, for accurate measurements, no adjustment is necessary for a dose calibrator setting when measuring different dose calibrators of F-18 FDG activity prescriptions.
Humans
;
Korea
;
Nuclear Medicine
;
Quality Control
;
Radioactivity
6.Comparison of F-18 FDG Radioacitivity to Determine Accurate Dose Calibrator Activity Measurements.
Gye Hwan JIN ; Dae Cheol KWEON ; Ki Baek OH ; Hoon Hee PARK ; Jung Yul KIM ; Min Soo PARK ; Dae Sung PARK
Korean Journal of Medical Physics 2009;20(3):159-166
Obviously, the administration of the prescribed amount of activity to the patient requires proper operation of the dose calibrator, which shall be verified by implementing the required quality control on the instrument. This investigation examined the accuracy and precision of dose calibrator activity measurement of the radiopharmaceutical F-18 FDG. To investigate the status of the nuclear medicine centers in Korea for the performance of dose calibrators, 10 centers providing PET/CT system services in Korea were inspected in 2008. We measured accuracy and precision in 10 equipments in consideration of PET/CT model, installation area, and installation time. According to the results of comparative analysis of 10 dose calibrators used to measure radioactivity of F-18 FDG, accuracy was -5.00~4.50% and precision was 0.05~0.45%, satisfying the international standards, which are accuracy +/-10% and precision +/-5%. This study demonstrated that, for accurate measurements, no adjustment is necessary for a dose calibrator setting when measuring different dose calibrators of F-18 FDG activity prescriptions.
Humans
;
Korea
;
Nuclear Medicine
;
Quality Control
;
Radioactivity
7.Evaluation of nutrient and food intake status, and dietary quality according to abdominal obesity based on waist circumference in Korean adults: Based on 2010-2012 Korean National Health and Nutrition Examination Survey.
Myeong Seong KIM ; Dae Cheol KWEON ; Yun Jung BAE
Journal of Nutrition and Health 2014;47(6):403-415
PURPOSE: This study was conducted in order to investigate the nutrient and food intake status, and dietary quality in Korean adults according to abdominal obesity based on waist circumference. METHODS: We analyzed data from the combined 2010~2012 KNHANES (Korean National Health and Nutrition Examination Survey). The analysis included 6,974 adults aged 40 to 64 years. In this study, according to abdominal obesity based on waist circumference (male > or = 90 cm, female > or = 85 cm), we classified the subjects into the obesity group (male, n = 775, female, n = 1,113) and control group (male, n = 2,038, female, n = 3,048). The nutrient and food group intake, ND (nutrient density), NAR (nutrient adequacy ratio), MAR (mean adequacy ratio), INQ (index of nutritional quality), DDS (dietary diversity score), and DVS (dietary variety score) were analyzed using data from the 24-recall method. RESULTS: For male, no significant difference in quality index of the diet was observed between the obesity group and the normal group. In female, in diet quality (ND, NAR, and INQ), vitamin B2 (ND, NAR, and INQ) calcium (NAR), phosphorous (ND, INQ) and potassium (ND) of the obesity group was significantly lower than those of the control group. DDS and DVS in the obesity group (3.57, 30.95) were significantly lower than those of the control group (3.68, 32.84) (p = 0.0043, 0.0002). DVS (DVS > or = 39.9) showed association with lower risk of waist obesity in a logistic regression model after adjustments for multiple confounding factors including age, education, income, alcohol intake frequency, smoking, physical activity, energy intake, and body mass index (OR: 0.616, 95% CI: 0.420-0.903). CONCLUSION: In conclusion, females with abdominal obesity had lower micronutrient intake quality, DVS than those of the control group. In Korean females, food intake variety can adversely affect waist circumference.
Adult*
;
Body Mass Index
;
Calcium
;
Diet
;
Eating*
;
Education
;
Energy Intake
;
Female
;
Humans
;
Logistic Models
;
Male
;
Micronutrients
;
Motor Activity
;
Nutrition Surveys*
;
Obesity
;
Obesity, Abdominal*
;
Potassium
;
Riboflavin
;
Smoke
;
Smoking
;
Waist Circumference*
8.Subcutaneous Injection Contrast Media Extravasation : 3D CT Appearance.
Dae Cheol KWEON ; Tae Hyung KIM ; Sung Hwan YANG ; Beong Gyu YOO ; Myeong Goo KIM ; Peom PARK
Korean Journal of Medical Physics 2005;16(1):47-51
We report a case of an accidental extravasation of contrast material. A large-volume extravasation occurred in an adult during spiral contrast-enhanced CT. The amount of contrast material extravasated was 47 ml. The patient had a swelling of the dorsum right hand. The extravasation injury site was determined by CT scanning. The extavasation case was examined using five separate display techniques: axial, multi planar reformation (MPR), maximum intensity projection (MIP), volume rendering, and shaded-surfaced display (SSD). This paper introduces extravasation with the CT and the three-dimensional appearance.
Adult
;
Contrast Media*
;
Extravasation of Diagnostic and Therapeutic Materials*
;
Hand
;
Humans
;
Injections, Subcutaneous*
;
Tomography, X-Ray Computed
9.Effect of mucilage from yam on activation of lymphocytic immune cells.
Cheol Min JANG ; Dae Hyuk KWEON ; Jong Hwa LEE
Nutrition Research and Practice 2007;1(2):94-99
The immunostimulating activities of mucilage fraction from yam were investigated. The proliferation of BSA-primed lymph node cells was enhanced between 4.1- to 10.9-fold compare to control, when cultured with 1 to 25 microgram/mL of yam-mucilage fraction. It showed strong immunopotentiating activity than ginseng extract and as remarkable as Bifidobacterium adolescentis M101-4 known as a positive immunostimulator. Mitogenicity to lymph node cells was fully induced by concanavalin A and lipopolysaccharide. The proliferation of splenocytes and Peyer's patch cells was enhanced between 5.0- to 14.1-fold and 2.4- to 6.4-fold, respectively, when cultured with 1 to 25 microgram/mL of yam-mucilage fraction. It enhanced the production of cytokines such as tumor necrosis factor-alpha and IL-6 in the culture of RAW 264.7 macrophage cells. In the culture of lipopolysaccharide-stimulated RAW 264.7 cells, production of cytokines was as similar as compared to controls. In unstimulated RAW 264.7 cells, both tumor necrosis factor-alpha and IL-6 production were enhanced between 15.6- to 60.1-fold and 2.3- to 9.1-fold, respectively. Mucilage fraction from yam is expected to be a safe immunopotentiator to maintain the host immunity and develop a physiologically functional food.
Bifidobacterium
;
Concanavalin A
;
Cytokines
;
Dioscorea*
;
Functional Food
;
Immunization
;
Interleukin-6
;
Lymph Nodes
;
Macrophages
;
Panax
;
Tumor Necrosis Factor-alpha
10.An Experimental Study on Telepathology System for the Optimum Image.
Dae Cheol KWEON ; Ho Young BYUN ; Joon Hoe EOM ; Rae Woong PARK ; Peom PARK
Journal of Korean Society of Medical Informatics 2001;7(2):93-103
This study is intended to the diagnostic accuracy and reproducibility rate according to the input devices and the video signals, potential technical problems of the telepathology system and possible physical and psychological impacts. Web based in telepathology system had been developed and in use, but their functional capability and diagnostic accuracy are considered to be inferior to those of conventional optical microscope. We devised a telepathology system using our existing microscope equipped with CCD camera unit that has no restriction of network speed. Total 55 histopathologic cases from various organs were selected. Three pathologists are involved in making diagnoses. The resulting diagnostic accuracies were 1CCD camera with composite video signal was 86.2%, 3CCD camera with composite video signal was 93.1% and 3CCD camera with component video signal was 95.0%. The 3CCD camera with component video signal resulted 95.0% diagnostic accuracy and was superior to 1CCD and 3CCD camera with composite video signal. At this time of problems were not noted in the monitor quality.
Diagnosis
;
Telepathology*