• Korean Journal of Radiology
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• 제21권11호
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• pp.1256-1264
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• 2020

Objective: Lung segmentation using volumetric quantitative computed tomography (CT) analysis may help predict outcomes of patients with coronavirus disease (COVID-19). The aim of this study was to investigate the relationship between CT volumetric quantitative analysis and prognosis in patients with COVID-19. Materials and Methods: CT images from patients diagnosed with COVID-19 from February 18 to April 15, 2020 were retrospectively analyzed. CT with a negative finding, failure of quantitative analysis, or poor image quality was excluded. CT volumetric quantitative analysis was performed by automated volumetric methods. Patients were stratified into two risk groups according to CURB-65: mild (score of 0-1) and severe (2-5) pneumonia. Outcomes were evaluated according to the critical event-free survival (CEFS). The critical events were defined as mechanical ventilator care, ICU admission, or death. Multivariable Cox proportional hazards analyses were used to evaluate the relationship between the variables and prognosis. Results: Eighty-two patients (mean age, 63.1 ± 14.5 years; 42 females) were included. In the total cohort, male sex (hazard ratio [HR], 9.264; 95% confidence interval [CI], 2.021-42.457; p = 0.004), C-reactive protein (CRP) (HR, 1.080 per mg/dL; 95% CI, 1.010-1.156; p = 0.025), and COVID-affected lung proportion (CALP) (HR, 1.067 per percentage; 95% CI, 1.033-1.101; p < 0.001) were significantly associated with CEFS. CRP (HR, 1.164 per mg/dL; 95% CI, 1.006-1.347; p = 0.041) was independently associated with CEFS in the mild pneumonia group (n = 54). Normally aerated lung proportion (NALP) (HR, 0.872 per percentage; 95% CI, 0.794-0.957; p = 0.004) and NALP volume (NALPV) (HR, 1.002 per mL; 95% CI, 1.000-1.004; p = 0.019) were associated with a lower risk of critical events in the severe pneumonia group (n = 28). Conclusion: CRP in the mild pneumonia group; NALP and NALPV in the severe pneumonia group; and sex, CRP, and CALP in the total cohort were independently associated with CEFS in patients with COVID-19.

• 한국지하수토양환경학회지:지하수토양환경
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• 제18권5호
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• pp.1-6
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• 2013

This study was performed to develop a method for quantitative analysis obtaining the amount of calcium carbonate minerals formed when Ca salts biomimetically reacted with carbon dioxide. There were two methods compared; 1) volumetric calcimeter method that determining the amount of released carbon dioxide after calcium carbonate minerals were acidified by 4N HCl and 2) Thermogravimetry-Differential Thermal Analysis (TG-DTA) adopting differential decomposition temperature breaking-up the structural link within calcium carbonate minerals. The comparisons were made by batch experiment (i.e., biocalcification process) along with control (i.e., nominal concentration of $CaCO_3$ prepared). For the control, TG-DTA took a minor root mean square deviation (RMSD) of 1.1~5.9 mg, whereas volumetric calcimeter exposed a greater RMSD of 28.3 mg. For the biocalcification, the amount of $CaCO_3$ was more precisely obtained for TG-DTA rather than that of volumetric calcimeter. It was decided that TG-DTA was more successfully used for quantitative analysis to observe the amount of calcium carbonate minerals derived from biocalcification.

• 한국지하수토양환경학회지:지하수토양환경
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• 제26권6호
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• pp.95-105
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• 2021

Extensive groundwater abstraction has been recognized as one of the major challenges in management of coastal groundwater. The purpose of this study was to assess potential changes of groundwater distribution of northeastern Jeju Island over 10-year duration, where brackish water have been actively developed. To quantitatively estimate the coastal groundwater resources, numerical simulations using three-dimensional finite-difference density-dependent flow models were performed to describe spatial distribution of the groundwater in the aquifer under various pumping and recharge scenarios. The simulation results showed different spatial distribution of freshwater, brackish, and saline groundwater at varying seawater concentration from 10 to 90%. Volumetric analysis was also performed using three-dimensional concentration distribution of groundwater to calculate the volume of fresh, brackish, and saline groundwater below sea level. Based on the volumetric analysis, a quantitative analysis of future seawater intrusion vulnerability was performed using the volume-based vulnerability index adopted from the existing analytical approaches. The result showed that decrease in recharge can exacerbate vulnerability of coastal groundwater resources by inducing broader saline area as well as increasing brackish water volume of unconfined aquifers.

• 핵의학기술
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• 제28권1호
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• pp.57-69
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• 2024

Purpose: Quantitative analysis through count measurement in nuclear medicine planar images is limited by analysis techniques that are useful for obtaining various clinical information or by organ overlap or artifacts in actual clinical practice. On the other hand, the use of SPECT tomography images is quantitative analysis using volume rather than planar, which is not only free from problems such as projection overlap, but also has excellent quantitative accuracy. In the use of developing SPECT quantitative analysis technology, this study aims to compare the accuracy of quantitative analysis between ROI of the conventional planar images and VOI of the SPECT tomographic images in evaluating the count change happened by the volume change of the source. Materials and Methods: A ^99mTcO₄^- source(200.17 MBq) was filled with sterilized water in the syringe to create a phantom with an inner diameter volume of 60 cc, and a planar image and a SPECT image were obtained by reducing the volume by 15 cc (25%) respectively. ROI and VOI(threshold: 1~45%, 5% interval) were set for each image obtained to estimate true count and measure the total count, and compared with the preseted volumetric change rate(%). Results: When volume changes of 25%, 50%, and 75% occurred in the initial volume of 60 cc(100%) of the phantom, the average count changes of the measured planar image were 26.8%, 53.2%, 77.5%, and the average count changes of the SPECT image were 24.4%, 50.9%, and 76.8%. In this case, the VOI size(cm³) set showed an average change rate of 25.4%, 51.1%, and 76.6%. The highest threshold value for the accuracy of radioactive concentration by VOI size (average error -1.03%) was 35%, and the VOI size of the same threshold had an error of -17.1% on average compared to the actual volume. Conclusion: On average, the count-based volumetric change rate in nuclear medicine images was able to track changes more accurately using VOI than ROI, but there was no significant difference with relatively similar value. However, the accuracy of radioactive concentration according to individual VOI sizes did not match, but it is considered that a relatively accurate quantitative analysis can be expected when the size of VOI is set smaller than the actual volume.

• Korean Journal of Radiology
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• 제22권11호
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• pp.1797-1808
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• 2021

Objective: To determine whether volumetric CT texture analysis (CTTA) using fully automatic tumor segmentation can help predict recurrence-free survival (RFS) in patients with intrahepatic mass-forming cholangiocarcinomas (IMCCs) after surgical resection. Materials and Methods: This retrospective study analyzed the preoperative CT scans of 89 patients with IMCCs (64 male; 25 female; mean age, 62.1 years; range, 38-78 years) who underwent surgical resection between January 2005 and December 2016. Volumetric CTTA of IMCCs was performed in late arterial phase images using both fully automatic and semi-automatic liver tumor segmentation techniques. The time spent on segmentation and texture analysis was compared, and the first-order and second-order texture parameters and shape features were extracted. The reliability of CTTA parameters between the techniques was evaluated using intraclass correlation coefficients (ICCs). Intra- and interobserver reproducibility of volumetric CTTAs were also obtained using ICCs. Cox proportional hazard regression were used to predict RFS using CTTA parameters and clinicopathological parameters. Results: The time spent on fully automatic tumor segmentation and CTTA was significantly shorter than that for semi-automatic segmentation: mean ± standard deviation of 1 minutes 37 seconds ± 50 seconds vs. 10 minutes 48 seconds ± 13 minutes 44 seconds (p < 0.001). ICCs of the texture features between the two techniques ranged from 0.215 to 0.980. ICCs for the intraobserver and interobserver reproducibility using fully automatic segmentation were 0.601-0.997 and 0.177-0.984, respectively. Multivariable analysis identified lower first-order mean (hazard ratio [HR], 0.982; p = 0.010), larger pathologic tumor size (HR, 1.171; p < 0.001), and positive lymph node involvement (HR, 2.193; p = 0.014) as significant parameters for shorter RFS using fully automatic segmentation. Conclusion: Volumetric CTTA parameters obtained using fully automatic segmentation could be utilized as prognostic markers in patients with IMCC, with comparable reproducibility in significantly less time compared with semi-automatic segmentation.

• 대한기계학회논문집B
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• 제25권4호
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• pp.561-571
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• 2001

The standard uncertainty of flowrate measurement is obtained by combining that of independent variables. Gravimetric and volumetric method were applied to determine the flowrate and the standard uncertainties of flowrate measurement by both methods were evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainties of determining the flowrate were estimated from the sensitivity coefficient and the standard uncertainty of independent variables. For practical application, the methods for evaluating and expressing uncertainty in flow measurement were discussed. It was found that the uncertainties of the weighing and time measurement in gravimetric method, the volume and time measurement in volumetric method have dominant influence on that of flowrate measurement. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of flowrate measurement is shown clearly.

• 한국방사선학회논문지
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• 제5권5호
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• pp.255-260
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• 2011

본 연구는 흉부 CT 검사 시 늑골 골절 환자를 대상으로 3차원 체적 재구성 기법의 유용성에 대해 알아보고자 하였다. 임상에서 주로 이용 하는 재구성기법인 다평면재구성(MPR), 3차원 체적 영상 기법(VRT)을 적용하여 영상데이터를 각 각 정량적 방법과 정성적 방법으로 비교 분석하였다. 재구성 영상의 분석 및 평가결과 늑골 골절 환자의 흉부 CT 검사 시 조영 전 원 자료를 이용하여 3차원 체적영상으로 재구성 하는 것이 보다 더 인공 음영을 최소화 시켰으며, 늑골 골절 판단 및 3차원 체적 영상 재구성 소요시간이 단축 됨을 알 수 있었다.

• 대한기계학회논문집B
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• 제24권10호
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• pp.1388-1398
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• 2000

A pipe prover is a flowmeter calibrator used in flow measurement field. Gravimetric and volumetric methods were applied to determine the basic volume of the pipe prover. Uncertainty of its basic volume measurement was evaluated in accordance with the procedure recommended by International Organization for Standardization. The combined standard uncertainty of determining the basic volume was estimated from the sensitivity coefficient and the standard uncertainty of independent variables. It was found that the uncertainties of the weighing and volume measurements have dominant influence on that of the basic volume determination. With the quantitative analysis of the sensitivity coefficient, the contribution of the each variable uncertainty to the combined standard uncertainty of the basic volume is shown clearly.

• 대한기계학회논문집A
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• 제36권2호
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• pp.165-171
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• 2012

본 연구는 3 축 공작기계에 있어 기하학적 오차가 체적 오차에 미치는 영향을 해석적 방법으로 분석하는데 목적이 있다. 먼저 기하학적 오차가 공작기계의 체적 오차에 미치는 영향을 제시하는 수학적 모델인 오차합성모델에 대해 분석한다. 민감도 분석은 분산 기반의 방법(Variance based method)을 사용하였으며 해석적 방법으로 분석하기 위해 평균 및 분산에 대해 목적 함수의 유형별로 그 해를 제시한다. 마지막으로 3 축 공작기계의 예를 들어 민감도 분석을 하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3045-3050
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• 2013

Purpose: Hepatic resection is arguably the preferred treatment for huge hepatocellular carcinoma (H-HCC). Estimating the remnant liver volume is therefore essential. This study aimed to evaluate the feasibility of using computer-assisted volumetric analysis for this purpose. Methods: The study involved 40 patients with H-HCC. Laboratory examinations were conducted, and a contrast CT-scan revealed that 30 cases out of the participating 40 had single-lesion tumors. The remaining 10 had less than three satellite tumors. With the consensus of the team, two physicians conducted computer-assisted 3D segmentation of the liver, tumor, and vessels in each case. Volume was automatically computed from each segmented/labeled anatomical field. To estimate the resection volume, virtual lobectomy was applied to the main tumor. A margin greater than 1 cm was applied to the satellite tumors. Resectability was predicted by computing a ratio of functional liver resection (R) as (Vresected-Vtumor)/(Vtotal-Vtumor) x 100%, applying a threshold of 50% and 60% for cirrhotic and non-cirrhotic cases, respectively. This estimation was then compared with surgical findings. Results: Out of the 22 patients who had undergone hepatectomies, only one had an R that exceeded the threshold. Among the remaining 18 patients with non-resectable H-HCC, 12 had Rs that exceeded the specified ratio and the remaining 6 had Rs that were < 50%. Four of the patients who had Rs less than 50% underwent incomplete surgery due to operative findings of more extensive satellite tumors, vascular invasion, or metastasis. The other two cases did not undergo surgery because of the high risk involved in removing the tumor. Overall, the ratio of functional liver resection for estimating resectability correlated well with the other surgical findings. Conclusion: Efficient pre-operative resectability assessment of H-HCC using computer-assisted volumetric analysis is feasible.