• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.933-939
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• 2019

The purpose of this study is to provide basic clinical data by evaluating images, measuring absorbed dose and effective dose by using high resolution CT and low dose CT by using anthropomorphic chest phantom and glass dosimeter. Tissue dose was measured by inserting a glass dosimeter into the anthropomorphic chest phantom. A 64-slice CT system (SOMATOM Sensation 64, Siemens AG, Forchheim, Germany) and CARE Dose 4D were used, and the parameters of the high resolution CT were 120 kVp, Eff. Scan parameters of mAs 104, scan time 7.93 s, slice 1.0 mm (Acq. 64 × 0.6 mm), convolution kernel (B60f sharp) were used, and low dose CT was 120 kVp, Eff. mAs 15, scan time 7.41 s, slice 3.0 mm (Acq. 64 × 0.6 mm), scan of convolution kernel B50f medium sharp. CTDIvol was measured at 8.01 mGy for high resolution CT and 1.18 mGy for low dose CT. Low dose CT scans showed 85.49% less absorbed dose than high resolution CT scans.

• Tuberculosis and Respiratory Diseases
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• v.57 no.6
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• pp.515-521
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• 2004

With the increasing resolution of modern CT scanners, analysis of the larger numbers of images acquired in a lung screening exam or diagnostic study is necessary, which also needs high accuracy and reproducibility. Recent developments in the computerized analysis of medical images are expected to aid radiologists and other healthcare professional in various diagnostic tasks of medical image interpretation. This article is to provide a brief overview of some of computer-aided diagnosis schemes in chest CT.

• Journal of Preventive Medicine and Public Health
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• v.23 no.3 s.31
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• pp.262-273
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• 1990

In order to assess the method which is more sensitive one to detect the early change of lung tissue by the inhaled dust, we have performed the various medical examinations such as chest radiography, pulmonary function test, high resolution chest CT, brnchoalveolar lavage and lung biopsy used bronchoscope and ultrathin bronchoscopy examination to 48 persons. The control group were 8 persons who did not exposed to dust, 40 cases of the experimental group have professionally exposed to the mineral dust. The results were as follows 1. The total number of cells in bronchoalveolar lavage was significantly increased in all of the pneumoconiosis group classified by chest and high resolution chest CT. 2. The composition rate of macrophage to the total number of cells in bronchoalveolar lavage fluid was significantly decreased in all of the pneumoconiosis group compared with the control group. 3. The composition rate of neutophils and lymphocytes to the total number of cells in bronchoalveolar lavage fluid was significantly increased in all of the pneumoconiosis group compared with the control group. 4. The forced expiratory volume in one second ($FEV_{1-0}$), maximal mid-expiratory flow (MMF), and maximal voluntary ventilation (MVV) were significantly increased only in the group of the progressed pneumoconiosis relatively. 5. We observed submucosal edema, anthracotic pigmentation and granuloma formation in transbronchial lung biopsy of the suspected pneumoconiosis (category 0/1) case which is thought to the early change of coal workers' pneumoconiosis.

• Journal of Chest Surgery
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• v.32 no.4
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• pp.383-387
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• 1999

Background: We analysed simple chest PA and high-resolution CT findings in patients with spontaneous pneumothorax in order to help selecting the kind of treatment, provide a guidline during surgical treatment, and to recognize the bulla which may not be detected by simple radiographs or may be a potential cause of recurrence. Material and Method: We retrospectively analysed the presence and number of bulla in each side, combined pulmonary disease on simple chest films and high-resolution CT, and methods and frequency of the treatment in 70 patients with spontaneous pneumothorax excluing traumatic origin. Result: 45 patients were revealed primary spontaneous pneumothorax, and the remaining 25 patients were revealed secondary spontaneous pneumothorax. All secondary spontaneous pneumothorax were from the longstanding sequelle of pulmonary tuberculosis. The patients with primary spontaneous pneumothorax group was younger(mean:26.0 years old) than secondary group (mean: 44.1 years old). On simple radiography, bulla was detected in 16 patients(30.2%). On HRCT, the bulla was detected in 53 patients(75.7%) of the total 70 patients. In 48 patients(68.6%), the bulla or bleb was noted in ipsilateral side to the pneumothorax, and 34 patients(48.6%) of them showed bulla or bleb bilaterally. 39 patients(55.7%) showed bulla or bleb in contralateral side. The number of bulla or bleb was variable. In secondary spontaneous pneumothorax group, the incidence of multiple(more than 10) bulla or bleb was higher than primary type. Most of the patients were treated by thoracostomy(36 patients) or bullectomy( 7 patients). Conclusion: HRCT was superior to detect bulla and analyse the combined pulmonary disease than simple radiography. Therefore, HRCT can help to determine the mothod of treatment, provide a guidline during surgical treatment, and notify the bulla as a possible cause of recurrent pneumothorax.

• Journal of Radiation Industry
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• v.11 no.3
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• pp.131-137
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• 2017

To compare the radiation dose and image noise of low dose computed tomography (CT) and high resolution CT using the fixed tube current technique and automatic tube current modulation (CARE Dose 4D). Chest CT and human anthropomorphic phantom were used the RPL (radiophotoluminescence) dosimeters. For image evaluation, standard deviation of mean CT attenuation coefficient and CT attenuation coefficient was measured using ROI analysis function. The effective dose was calculated using CTDIvol and DLP. CARE Dose 4D was reduced by 74.7% and HRCT by 64.4% compared to the fixed tube current technique in low dose CT of chest phantom. In CTDIvol and DLP, the dose of CARE Dose 4D was reduced by fixed tube current technique. For effective dose, CARE Dose 4D was reduced by 47% and HRCT by 46.9% compared to the fixed tube current method, and the dose of CARE Dose 4D was significantly different (p<.05). Noise in the image was higher than that in the fixed tube current technique. Noise difference in the image of CARE Dose 4D in low dose CT was significant (p<.05). The low radiation dose and the noise difference of the CARE Dose 4D were compared with the fixed tube current technique in low dose CT and HRCT using chest phantom. The radiation doses using CARE Dose 4D were in accordance with the national and international dose standards. CARE Dose 4D should be applied to low dose CT and HRCT for clinical examination.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.329-336
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• 2016

The purpose of this study was to evaluate the usefulness of low-dose CT (LDCT) for emphysema compared with high-resolution CT (HRCT). Measurements of radiation dose and noise were repeated 3 times in same exposure condition which was similar with obtaining HRCT and LDCT images. We analysed reading results of 146 subjects. Six images per participants selected for emphysema grading. Emphysema was graded for all 6 zones on the left and right sides of the lungs by the consensus reading of two chest radiologists using a 4-point scale. Between the HRCT and LDCT images, diagnostic differences and agreements for emphysema were analyzed by McNemar's and unweighted kappa tests, and radiation doses and noise by a Mann-Whitney U-test, using the SPSS 19.0 program. Radiation dose from HRCT was significantly higher than that of LDCT, but the noise was significantly lower in HRCT than in LDCT. Diagnostic agreement for emphysema between HRCT and LDCT images was excellent (k-value=0.88). Emphysema grading scores were not significantly different between HRCT and LDCT images for all six lung zones. Emphysema grading scores from LDCT images were significantly correlated with increased scores on HRCT images (r=0.599, p < 0.001). Considering the tradeoff between radiation dose and image noise, LDCT could be used as the gold standard method instead of HRCT for emphysema detection and grading.

• Korean Journal of Digital Imaging in Medicine
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• v.17 no.1
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• pp.13-18
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• 2015

Purpose : Skip the repetitive HRCT axial scan in order to reduce the exposure of patients during chest HRCT scan, Helical Scan Data into a reconstructed image, and exposure of the patient change and visually evaluate the usefulness of the HRCT images. Materials and method : Patients were enrolled in the survey are 50 people who underwent chest CT scans of patients who presented to the hospital from January 2015 to March 2015. 50 people surveyed 22 people men and 28 people women people showed an average distribution of 30 to 80 years age was 48 years. 50 patients to Somatom Sensation 64 ch (Siemens) model with 120 kVp tube voltage to a reference mAs tube current to mAs (Care dose, Siemens) as a whole, including the lungs and the chest CT scan was performed. Scan upon each patient CARE dose 4D (Automatic exposure control, Siemens Medical Solution Erlangen, Germany) was to maintain the proper radiation dose scan every cross-section through a device that automatically adjusts the tube current of. CT scan is the rotation time of the Tube slice collimation, slice width 0.6 mm, pitch factor was made under the terms of 1.4. CT scan obtained after the raw data (raw data) to the upper surface of the axial images and coronal images for each slice thickness 1 mm, 5 mm intervals in the high spatial frequency calculation method (hight spatial resolution algorithm, B60 sharp) was the use of the lung window center -500 HU, windows were reconstructed into images in the interval -1000 HU to see. Result : 1. Measure the total value of DLP 50 patients who proceed to chest CT group A (Helical Scan after scan performed with HRCT) and group B (Helical Scan after the HR image reconstruction to the original data) compared with the group divided, analysis As a result of the age, but show little difference for each age group it had a decreased average dose of about 9%. 2. A Radiation read the results of the two Radiologist and a doctor upper lobe and middle lobe of the lung takes effect the visual evaluation is not a big difference between the two images both, depending on the age of the patient, especially if the blood vessels of the lower lobe (A: 3.4, B: 4.6) and bronchi(A: 3.8, B4.7) image shake caused by breathing in anxiety (blurring lead) to the original data (raw data) showed that the reconstructed image is been more useful in diagnostic terms. Conclusion : Scan was confirmed a continuous, rapid motion video to get Helical scan is much lower lobe lung reduction in visual blurring, Helical scan data to not repeat the examination by obtaining HRCT images reorganization reduced the exposure of the patient.

• Tuberculosis and Respiratory Diseases
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• v.43 no.3
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• pp.388-402
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• 1996

Background : To compare the diagnostic accuracies of High-resolution CT(HRCI) and chest radiography in the diagnosis of diffuse infiltrative lung disease(DILD). Methods : This study included ninety-nine patients with a diagnosis of acute or chronic DILD, representing 20 different diseases. Twelve normal subjects were included as control. The disease state was confirmed either pathologically or clinically. Radiographs and CT scans were evaluated separately by three independent observers without knowledge of clinical and pathologic results. The observers listed three most likely diagnoses and recorded degree of confidence. Results : The sensitivity of HRCT in the detection of DILD was 98.9% compared to 97.9% of chest radiography. Overall, a correct first-choice diagnosis was made in 48% using chest radiographs and in 60% using HRCT images. The correct diagnosis was among the top-three choices in 64% when chest radiographs were used, and in 75% when HRCT images were reviewed. Overally a confident diagnosis was reached more often with HRCT(55%) than with chest radiography(26%). The correct first-choice diagnosis increased remarkably when the HRCT was used in usual interstitial pneumonia, miliary tuberculosis, diffuse panbronchiolitis and lymphangitic carcinomatosis. Conclusion : HRCT is confirmed to be superior to conventional radiography in the detection and accurate diagnosis of DILD. HRCT is especially valuable in the diagnosis of usual interstitial pneumonia, miliary tuberculosis, diffuse panbronchiolitis, and lymphangitic carcinomatosis.

• Tuberculosis and Respiratory Diseases
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• v.44 no.5
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• pp.1184-1193
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• 1997

Lymphangioleiomyomatosis(LAM) is rare and essentially limited to women in the reproductive ages. A 39-year-old female was admitted due to progressive exertional dyspnea and intermittent productive cough. Chest PA showed marked hyperinflation of the lung associated with a diffuse reticulo-nodular pattern. High resolution CT scan of the thorax demonstrated that diffusely scattered thin-walled cysts were distributed throughout the bilateral lung fields. Abdominal CT scan showed variable sized multiple angiomyolipoma of both kidney. By open lung biopsy, she was diagnosed as pulmonary LAM associated with Tuberous sclerosis and renal Angiomyolipoma. We present the case and discuss the connection between pulmonary LAM and Tuberous sclerosis.

• The Journal of the Korea Contents Association
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• v.2 no.4
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• pp.23-29
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• 2002

This paper suggest the image compression that is needed to process PACS in medical information system. The image decoding method is used Linear-predictor and Lloyd-Max quantizer(quantization) in the Wavelet transform domain. Wavelet Transform Method is processed the multi-resolution by dividing image into 10 sub-bands of 3 levels. Low frequency domain that is sensitive to human visual characteristic is encoded by DPCM which is lossless encoding methods, and Lloyed-Max quantizer, the optimal quantizer for reducing ringing and aliasing in the image of inter sub-band, is used in the remaining high frequency domain of sub-band. The examination verifies that decompressed images are superior by the result that PSNR is 28.53dB on the input image, 512$\times$152 abdominal CT image and Chest image.