• 대한디지털의료영상학회논문지
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• 제16권2호
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• pp.9-14
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• 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
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• 제25권1호
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• pp.62-73
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• 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
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• 제43권6호
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• pp.700-704
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• 2010

배경: 최근 양전자단층촬영/전산화단층촬영(PET/CT) 검사가 점차 보편화 되어가고 있다. 림프절 병기 진단에 있어서 CT와 PET/CT의 유용성 및 실효성에 대해 알아보고자 하였다. 대상 및 방법: 2006년 1월부터 2009년 8월까지 본원에서 악성종양으로 폐절제술을 받은 110명의 환자 중, 술 전 본원에서 조영증강 흉부전산화단층촬영 (CT)과 전신 양전자단층촬영/전산화단층촬영 결합영상(PET/CT fusion imaging, integrated PET/CT) 검사를 모두 시행 받고, 술 후 원발성 비소세포폐암을 진단 받은 48명의 환자들을 대상으로 하였다. 림프절을 superior mediastinal nodes, aortic nodes, inferior mediastinal nodes, 그리고 Nl nodes의 4군으로 분류하여 CT와 PET/CT의 진단력에 대한 통계분석을 실시하였다. 결과: 4개의 군 가운데, inferior mediastinal nodes를 제외한 나머지 군들은 CT보다 PET/CT에서 민감도가 향상되는 소견을 보였다. 하지만 두 검사의 진단력 차이를 각각의 군에 대해 McNemar's test를 사용하여 분석한 결과 통계적으로 유의한 차이는 보이지 않았다(p-values; superior mediastinal nodes=0.109, aortic nodes=1.000, inferior mediastinal nodes=0.625, Nl nodes=0.424). 결론: 본 연구에서 종격동 림프절에 대한 PET/CT의 진단력은 조영증강 CT와 비슷한 정도로 나타났다. 현재 PET/CT는 CT와 상호보완적인 수단으로써 사용되어야 할 것으로 사료되며, 앞으로 촬영 기술 및 판독 수준이 더욱 발전하고 결과들이 많이 축적되었을 때에는 보다 좋은 성적을 보일 것으로 생각된다.

• Korean Journal of Radiology
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• 제25권5호
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• pp.481-492
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• 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
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• 제42권5호
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• pp.414-418
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• 2008

간암의 정맥계 침범은 흔하나 심장 침범은 드물고 예후가 불량할 뿐 아니라 급사의 위험이 있다. 본 증례처럼 간세포암이 혈관계를 통해 우심방까지 전이된 경우 노작성 호흡곤란 같은 심부전에 의한 증상을 나타낼 수 있어서 간세포암의 간외 전이를 의심하기는 쉽지 않고, 원발 병소를 찾기 위해서 여러 가지 진단적 검사를 시행하여야 한다. F-18 FDG PET/CT는 기능적으로 암세포의 당대사 항진을 3차원적인 입체 영상으로 국소화하기 때문에 비침습적이며 경제적으로 간세포암의 침범 및 간외전이를 쉽게 확인할 수 있다. 저자들은 호흡곤란을 주소로 내원한 55세 남자 환자에서 PET/CT를 통해서 간세포암과 간세포암의 우심방 침범을 진단하는데 도움을 받았기에 이를 문헌고찰과 함께 보고하는 바이다.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2197-2204
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• 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.

• 대한영상의학회지
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• 제84권6호
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• pp.1391-1396
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• 2023

악성 림프종은 흉부 CT에서 결절, 종양, 폐 경화, 간유리음영 등 다양한 폐질환으로 나타날 수 있으며 이러한 폐 병변은 다른 질환의 양상과 유사하여 진단에 어려움을 줄 수 있다. 본 증례는 호흡곤란과 발열을 주 증상으로 하는 67세 남성 환자로 해당 환자의 흉부 CT상 크기가 작은 다발성 결절이 양측에 미만성으로 나타나 혈행성 전이, 좁쌀 결핵 또는 진균 감염을 의심해 볼 수 있었다. 그러나 추가적으로 시행한 혈액 검사, 영상 검사 및 조직 생검 결과 폐를 침범한 미만성 큰 B세포 림프종이 진단되었다. 저자들은 폐의 좁쌀 결절로 발현한 매우 드문 림프종을 보고한다. 환자의 적절한 진단을 위해서는 환자의 병력, 신체 진찰, 혈액 검사 및 영상 소견의 포괄적인 평가가 필요하다.

• 한국산학기술학회논문지
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• 제11권11호
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• pp.4411-4417
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• 2010

64채널 MDCT(multidetector computed tomography)와 128채널 DSCT(dual source computed tomography)를 이용한 관상동맥 전산화단층촬영 시 유효선량과 획득한 영상의 질을 평가함으로서 임상에서의 유용성을 평가하고자 하였다. 피폭선량은 선량길이곱(dose length product: DLP)에 흉부 조직의 가중치(0.017)을 곱하여 유효선량(mSv)으로 계산하였으며, 영상 평가는 심장촬영검사 후 영상의학과 전문의가 5점 Likert 척도(5점 최상)로 평가하였다. DLP 값은 64 채널 MDCT에서는 $851{\sim}1277\;mGy{\cdot}cm$ (평균 유효선량: 17.23mSv), 128 채널 DSCT에서는 $82{\sim}110\;mGy{\cdot}cm$ (평균 유효선량: 1.58mSv)로 각각 분포하였다. 영상 평가점수는 64 채널 MDCT에서 $3.31{\pm}0.62$(4점 이상 34명), 128channel DSCT에서 $4.05{\pm}0.46$(4점 이상 96명)으로 각각 나타났다. 유효선량은 64채널 MDCT에 비해 128채널 DSCT가 1/10 이상 감소함을 알 수 있었다. 영상 평가점수는 통계적으로 유의한 차이를 보였으며 4점 이상 점수의 빈도는 128채널 DSCT에서 2.8배 높게 나타났다. 결론적으로 관상동맥 전산화단층촬영검사에서는 128채널 DSCT가 64채널 MDCT에 비해 환자가 받는 유효선량은 감소하고 영상 평가점수는 높게 나타나 임상에서 보다 유용할 것으로 판단된다.

• 대한영상의학회지
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• 제84권1호
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• pp.253-262
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• 2023

목적 정상 면역 환자에서 폐 크립토코쿠스증의 컴퓨터단층촬영 영상 소견과 임상 양상에 대하여 분석해 보고자 하였다. 대상과 방법 2008년 1월부터 2019년 11월까지 흉부 컴퓨터단층촬영을 시행하였으며, 조직병리 학적 검사로 진단된 정상 면역 폐 크립토코쿠스 환자를 대상으로 후향적 분석을 시행하였다. 영상 소견은 주 영상 형태, 병변의 분포, 보조적 영상 소견으로 구분하였다. 혈청 크립토코쿠스 항원의 유무에 따른 임상 및 방사선학적 특징을 확인하기 위해 단변수 분석을 시행하였다. 결과 총 31명의 환자를 분석하였다(평균 연령: 60세, 범위 19-78세). 단일 폐엽에 국한된 단일 결절성 병변이 가장 흔한 주된 영상 소견이었다(14/31, 45.2%). 19명의 환자에서 혈청 크립토코쿠스 항원 검사를 시행하였다(19/31, 61.3%). 6명의 환자에서 혈청 크립토코쿠스 항원이 검출됐으며(6/19, 31.6%), 이들 모두 폐경결 우세 형태를 보였다. 혈청 크립토코쿠스 항원은 결절 우세 형태보다 폐경결 우세 형태에서 보다 유의미하게 검출되었다(p = 0.011). 결론 폐경결 형태의 CT 영상 소견을 보이고 혈청 크립토코쿠스 항원 검사가 양성을 보이는 조합은 정상 면역 폐 크립토코쿠스 환자의 진단에 도움이 될 수 있다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권18호
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• pp.7719-7724
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• 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.