• Korean Journal of Digital Imaging in Medicine
• /
• v.16 no.2
• /
• pp.9-14
• /
• 2014

Purpose: The purpose of this study has attempted to evaluate and compare the image evaluation and exposure dose by respectively applying Filtered Back Projection(FBP), the existing test method, and Adaptive Statistical Iterative Reconstruction(ASIR) with different values of tube voltage during the Low Dose Computed Tomography(LDCT). Materials and Methods: With the image reconstruction method as basis, Chest Phantom was utilized with the FBP and ASIR set at 10%, 20% respectively, and the change of Tube Voltage (100kVp, 120kVp). For image evaluation, Back ground noise, Signal to Noise ratio(SNR) and Contrast to Noise ratio(CNR) were measured, and, for dose evaluation, CTDIvol and DLP were measured respectively. The statistical analysis was tested with SPSS(ver. 22.0), followed by ANOVA Test conducted after normality test and homogeneity test. (p<0.05). Results: In terms of image evaluation, there was no outstanding difference in Ascending Aorta(AA) SNR and Infraspinatus Muscle(IM) SNR with the different values of ASIR application(p<0.05), but a significant difference with the different amount of tube voltage(p>0.05). Also, there wasn't noticeable change in CNR with ASIR and different amount of Tube Voltage (p<0.05). However, in terms of dose evaluation, CTDIvol and DLP showed contrasting results(p<0.05). In terms of CTDIvol, the measured values with the same tube voltage of 120kVp were 2.6mGy with No-ASIR and 2.17mGy with 20%-ASIR respectively, decreased by 0.43mGy, and the values with 100kVp were 1.61mGy with No-ASIR and 1.34mGy with 20%-ASIR, decreased by 0.27mGy. In terms of DLP, the measured values with 120kVp were $103.21mGy{\cdot}cm$ with No-ASIR and $85.94mGy{\cdot}cm$ with 20%-ASIR, decreased by $17.27mGy{\cdot}cm$(about 16.7%), and the values with 100kVp were $63.84mGy{\cdot}cm$ with No-ASIR and $53.25mGy{\cdot}cm$ with 20%-ASIR, a decrease by $10.62mGy{\cdot}cm$(about 16.7%). Conclusion: At lower tube voltage, the rate of dose significantly decreased, but the negative effects on image evaluation was shown due to the increase of noise. For the future, through the result of the experiment, it is considered that the method above would be recommended for follow-up patients or those who get health checkup as long as there is no interference on the process of diagnosis due to the characteristics of Low Dose examination.

• Korean Journal of Radiology
• /
• v.25 no.1
• /
• pp.62-73
• /
• 2024

Objective: This study aimed to determine the prevalence of vertebral venous congestion (VVC) in patients with chemoport insertion, evaluate the imaging characteristics of nodular VVC, and identify the factors associated with VVC. Materials and Methods: This retrospective single-center study was based on follow-up contrast-enhanced chest computed tomography (CT) of 1412 adult patients who underwent chemoport insertion between January 2016 and December 2016. The prevalence of venous stenosis, reflux, and VVC were evaluated. The imaging features of nodular VVC, including specific locations within the vertebral body, were analyzed. To identify the factors associated with VVC, patients with VVC were compared with a subset of patients without VVC who had been followed up for > 3 years without developing VVC after chemoport insertion. Toward this, a multivariable logistic regression analysis was performed. Results: After excluding 333 patients, 1079 were analyzed (mean age ± standard deviation, 62.3 ± 11.6 years; 540 females). The prevalence of VVC was 5.8% (63/1079), with all patients (63/63) demonstrating vertebral venous reflux and 67% (42/63) with innominate vein stenosis. The median interval between chemoport insertion and VVC was 515 days (interquartile range, 204-881 days). The prevalence of nodular VVC was 1.5% (16/1079), with a mean size of 5.9 ± 3.1 mm and attenuation of 784 ± 162 HU. Nodular VVC tended to be located subcortically. Forty-four patients with VVC underwent CT examinations with contrast injections in both arms; the VVC disappeared in 70% (31/44) when the contrast was injected in the arm contralateral to the chemoport site. Bevacizumab use was independently associated with VVC (odds ratio, 3.45; P < 0.001). Conclusion: The prevalence of VVC and nodular VVC was low in patients who underwent chemoport insertion. Nodular VVC was always accompanied by vertebral venous reflux and tended to be located subcortically. To avoid VVC, contrast injection in the arm contralateral to the chemoport site is preferred.

• Journal of Chest Surgery
• /
• v.43 no.6
• /
• pp.700-704
• /
• 2010

Background: For staging primary lung cancer, integrated positron emission tomography/computed tomography (PET/CT) imaging is popular. The purpose of this study was to evaluate the accuracy of PET/CT scanning in lymph nodal staging of lung cancer. Material and Method: We studied 48 patients who had received CT, PET/CT and pulmonary resections due to primary non-small cell lung cancer in our hospital between January 2006 and August 2009. Mediastinal lymph nodes were classified as superior mediastinal nodes, aortic nodes, inferior mediastinal nodes, or N1 nodes. We compared the power of CT and PET/CT for diagnosing pulmonary lymph nodes for each of the four types of nodes. Result: PET/CT was more sensitive than CT for all groups except inferior mediastinal nodes. However, the differences were not significant (McNemar's test: superior mediastinal nodes, p=0.109; aortic nodes, p=1.000; inferior mediastinal nodes, p=0.625, N1 nodes, p=0.424). Conclusion: The accuracy of PET/CT is similar to that of CT alone for staging lymph nodes. The two imaging modalities might be used as complementary, cooperative tools. We expect that integrated PET/CT will be found to be significantly mmore sensitive after more trials are done and more data is accumulated.

• Korean Journal of Radiology
• /
• v.25 no.5
• /
• pp.481-492
• /
• 2024

Objective: To evaluate the clinical and imaging characteristics of SARS-CoV-2 breakthrough infection in hospitalized immunocompromised patients in comparison with immunocompetent patients. Materials and Methods: This retrospective study analyzed consecutive adult patients hospitalized for COVID-19 who received at least one dose of the SARS-CoV-2 vaccine at two academic medical centers between June 2021 and December 2022. Immunocompromised patients (with active solid organ cancer, active hematologic cancer, active immune-mediated inflammatory disease, status post solid organ transplantation, or acquired immune deficiency syndrome) were compared with immunocompetent patients. Multivariable logistic regression analysis was performed to evaluate the effect of immune status on severe clinical outcomes (in-hospital death, mechanical ventilation, or intensive care unit admission), severe radiologic pneumonia (≥ 25% of lung involvement), and typical CT pneumonia. Results: Of 2218 patients (mean age, 69.5 ± 16.1 years), 274 (12.4%), and 1944 (87.6%) were immunocompromised an immunocompetent, respectively. Patients with active solid organ cancer and patients status post solid organ transplantation had significantly higher risks for severe clinical outcomes (adjusted odds ratio = 1.58 [95% confidence interval {CI}, 1.01-2.47], P = 0.042; and 3.12 [95% CI, 1.47-6.60], P = 0.003, respectively). Patient status post solid organ transplantation and patients with active hematologic cancer were associated with increased risks for severe pneumonia based on chest radiographs (2.96 [95% CI, 1.54-5.67], P = 0.001; and 2.87 [95% CI, 1.50-5.49], P = 0.001, respectively) and for typical CT pneumonia (9.03 [95% CI, 2.49-32.66], P < 0.001; and 4.18 [95% CI, 1.70-10.25], P = 0.002, respectively). Conclusion: Immunocompromised patients with COVID-19 breakthrough infection showed an increased risk of severe clinical outcome, severe pneumonia based on chest radiographs, and typical CT pneumonia. In particular, patients status post solid organ transplantation was specifically found to be associated with a higher risk of all three outcomes than hospitalized immunocompetent patients.

• Nuclear Medicine and Molecular Imaging
• /
• v.42 no.5
• /
• pp.414-418
• /
• 2008

The role of positron emission tomography (PET) with F-18 fluorodeoxyglucose (F-18 FDG) in the diagnosis of hepatocellulcar carcinoma (HCC) has been limited because of a variable FDG uptake in HCC. However, the usefulness of PET/CT for detecting extrahepatic metastasis and monitoring of the treatment response in HCC has been reported. A 55-year-old man with a hepatitis B surface antigen-positive, was admitted to our hospital due to dyspnea, general weakness and body weight loss for one month. Chest X-ray showed multiple reticulo-nodular densities on both lower lung fields, which implies metastatic lesions. F-18 FDG PET/CT revealed consecutively intense hypermetabolic mass in right hepatic lobe, inferior vena cava and right atrium. We report a case of HCC with IVC and right atrium invasion identified by F-18 FDG PET/CT.

• Journal of Electrical Engineering and Technology
• /
• v.10 no.5
• /
• pp.2197-2204
• /
• 2015

In recent years, medical image diagnosis has growing significant momentous in the medicinal field. Brain and lung image of patient are distorted with salt and pepper noise is caused by moving the head and chest during scanning process of patients. Reconstruction of these images is a most significant field of diagnostic evaluation and is produced clearly through techniques such as linear or non-linear filtering. However, restored images are produced with smaller amount of noise reduction in the presence of huge magnitude of salt and pepper noises. To eliminate the high density of salt and pepper noises from the reproduction of images, a new efficient fuzzy based median filtering algorithm with a moderate elapsed time is proposed in this paper. Reproduction image results show enhanced performance for the proposed algorithm over other available noise reduction filtering techniques in terms of peak signal -to -noise ratio (PSNR), mean square error (MSE), root mean square error (RMSE), mean absolute error (MAE), image enhancement factor (IMF) and structural similarity (SSIM) value when tested on different medical images like magnetic resonance imaging (MRI) and computer tomography (CT) scan brain image and CT scan lung image. The introduced algorithm is switching filter that recognize the noise pixels and then corrects them by using median filter with fuzzy two-sided π- membership function for extracting the local information.

• Journal of the Korean Society of Radiology
• /
• v.84 no.6
• /
• pp.1391-1396
• /
• 2023

Malignant lymphoma has various pulmonary manifestations on chest CT, including nodules, masses, areas of consolidation, and ground-glass opacity. These presentations can pose a diagnostic challenge, as they mimic other disease patterns. Herein, we report a case of diffuse large B-cell lymphoma (DLBCL) manifesting as miliary nodules in a 67-year-old male initially presenting with dyspnea and fever. Radiologic findings included diffuse, bilateral, multiple tiny nodules consistent with metastasis, miliary tuberculosis, and fungal infection. However, further investigations, including laboratory tests, imaging, and biopsies, led to the diagnosis of DLBCL involving the lungs. Herein we reported a rare case of lymphoma involvement of the lung presenting as miliary nodules. Accurate diagnosis relies on a comprehensive evaluation of the clinical history, physical features, laboratory test results, and imaging findings.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.11 no.11
• /
• pp.4411-4417
• /
• 2010

This study was retrospectively to compare the exposure dose and the imaging quality in coronary CT angiography by using the 64 channel multidetector computed tomography and the 128 channel DSCT. Effective dose was calculated dose length product (DLP) by multiplied the convention factor of chest (0.017). Imaging quality was assessed by radiologists using the 5-point Likert scale. The DLP was ranged from 851 to $1277mGy{\cdot}cm$ (mean: 17.23 mSv) in the 64 channel MDCT and from 82 to $110mGy{\cdot}cm$ (mean: 1.58 mSv) in the of 128 channel DSCT, respectively. The score of imaging quality was respectively $3.31{\pm}0.62$ in 64 channel MDCT and $4.05{\pm}0.46$ in the 128 channel DSCT. The exposure dose of 128 channel DSCT has decreased 1ess 1/10. The score of imaging quality was significant difference between two modalities and the frequency (>4 good) in the 128 channel DSCT is about three times than that of the 64 channel MDCT. Therefore, the 128 channel DSCT in coronary CT angiography is clinically more effective modality for both investigators and patients.

• Journal of the Korean Society of Radiology
• /
• v.84 no.1
• /
• pp.253-262
• /
• 2023

Purpose To assess the clinicoradiological features of pulmonary cryptococcosis in immunocompetent patients. Materials and Methods This retrospective study included immunocompetent patients who had been diagnosed with pulmonary cryptococcosis on the histopathologic exam and underwent chest CT between January 2008 and November 2019. Imaging features were divided into major imaging patterns, distributions, and ancillary imaging findings. Univariable analysis was performed to evaluate clinicoradiological features according to the presence of serum cryptococcal antigen. Results Thirty-one patients were evaluated (mean age: 60 years, range: 19-78 years). A single nodular lesion confined to a single lobe was the most common imaging pattern (14/31, 45.2%). Serum cryptococcal antigen tests were performed in 19 patients (19/31, 61.3%). The presence of serum cryptococcal antigen was observed in six patients (6/19, 31.6%), all of whom showed a consolidation-dominant pattern. The presence of serum cryptococcal antigen was significantly associated with the consolidationdominant pattern compared to those associated with a nodule-dominant pattern (p = 0.011). Conclusion A combination of CT findings of consolidation and a positive serum cryptococcal antigen test may be helpful for diagnosing pulmonary cryptococcosis in immunocompetent patients.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.18
• /
• pp.7719-7724
• /
• 2014

Background: Lymph node metastasis is believed to be a dependent negative prognostic factor of esophageal cancer. To explore detection methods with high sensitivity and accuracy for metastases to regional and distant lymph nodes in the clinic is of great significance. This study focused on clinical application of FDG PET/CT and contrast-enhanced multiple-slice helical computed tomography (MSCT) in lymph node staging of esophageal cancer. Materials and Methods: One hundred and fifteen cases were examined with enhanced 64-slice-MSCT scan, and FDG PET/CT imaging was conducted for neck, chest and upper abdomen within one week. The primary lesion, location and numbers of metastatic lymph nodes were observed. Surgery was performed within one week after FDG PET/CT detection. All resected lesions were confirmed histopathologically as the gold standard. Comparative analysis of the sensitivity, specificity, and accuracy based on FDG PET/CT and MSCT was conducted. Results: There were 946 lymph node groups resected during surgery from 115 patients, and 221 were confirmed to have metastasis pathologically. The sensitivity, specificity, accuracy of FDG PET/CT in detecting lymph node metastasis were 74.7%, 97.2% and 92.0%, while with MSCT they were 64.7%, 96.4%, and 89.0%, respectively. A significance difference was observed in sensitivity (p=0.030), but not the others (p>0.05). The accuracy of FDG PET/CT in detecting regional lymph node with or without metastasis were 91.9%, as compared to 89.4% for MSCT, while FDG PET/CT and MSCT values for detecting distant lymph node with or without metastasis were 94.4% and 94.7%. No significant difference was observed for either regional or distant lymph node metastasis. Additionally, for detecting para-esophageal lymph nodes metastasis, the sensitivity of FDG PET/CT was 72%, compared with 54.7% for MSCT (p=0.029). Conclusions: FDG PET/CT is more sensitive than MSCT in detecting lymph node metastasis, especially for para-esophageal lymph nodes in esophageal cancer cases, although no significant difference was observed between FDG PET/CT and MSCT in detecting both regional and distant lymph node metastasis. However, enhanced MSCT was found to be of great value in distinguishing false negative metastatic lymph nodes from FDG PET/CT. The combination of FDG PET/CT with MSCT should improve the accuracy in lymph node metastasis staging of esophageal cancer.