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Abadi E, Jadick G, Lynch DA, Segars WP, Samei E. Emphysema Quantifications With CT Scan: Assessing the Effects of Acquisition Protocols and Imaging Parameters Using Virtual Imaging Trials. Chest 2023; 163:1084-1100. [PMID: 36462532 PMCID: PMC10206513 DOI: 10.1016/j.chest.2022.11.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 11/01/2022] [Accepted: 11/23/2022] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND CT scan has notable potential to quantify the severity and progression of emphysema in patients. Such quantification should ideally reflect the true attributes and pathologic conditions of subjects, not scanner parameters. To achieve such an objective, the effects of the scanner conditions need to be understood so the influence can be mitigated. RESEARCH QUESTION How do CT scan imaging parameters affect the accuracy of emphysema-based quantifications and biomarkers? STUDY DESIGN AND METHODS Twenty anthropomorphic digital phantoms were developed with diverse anatomic attributes and emphysema abnormalities informed by a real COPD cohort. The phantoms were input to a validated CT scan simulator (DukeSim), modeling a commercial scanner (Siemens Flash). Virtual images were acquired under various clinical conditions of dose levels, tube current modulations (TCM), and reconstruction techniques and kernels. The images were analyzed to evaluate the effects of imaging parameters on the accuracy of density-based quantifications (percent of lung voxels with HU < -950 [LAA-950] and 15th percentile of lung histogram HU [Perc15]) across varied subjects. Paired t tests were performed to explore statistical differences between any two imaging conditions. RESULTS The most accurate imaging condition corresponded to the highest acquired dose (100 mAs) and iterative reconstruction (SAFIRE) with the smooth kernel of I31, where the measurement errors (difference between measurement and ground truth) were 35 ± 3 Hounsfield Units (HU), -4% ± 5%, and 26 ± 10 HU (average ± SD), for the mean lung HU, LAA-950, and Perc15, respectively. Without TCM and at the I31 kernel, increase of dose (20 to 100 mAs) improved the lung mean absolute error (MAE) by 4.2 ± 2.3 HU (average ± SD). TCM did not contribute to a systematic improvement of lung MAE. INTERPRETATION The results highlight that although CT scan quantification is possible, its reliability is impacted by the choice of imaging parameters. The developed virtual imaging trial platform in this study enables comprehensive evaluation of CT scan methods in reliable quantifications, an effort that cannot be readily made with patient images or simplistic physical phantoms.
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Affiliation(s)
- Ehsan Abadi
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University School of Medicine, Durham, NC; Department of Electrical & Computer Engineering, Duke University, Durham, NC; Medical Physics Graduate Program, Duke University, Durham, NC.
| | - Giavanna Jadick
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University School of Medicine, Durham, NC
| | - David A Lynch
- Department of Radiology, National Jewish Health, Denver, CO
| | - W Paul Segars
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University School of Medicine, Durham, NC; Medical Physics Graduate Program, Duke University, Durham, NC; Department of Biomedical Engineering, Duke University, Durham, NC
| | - Ehsan Samei
- Center for Virtual Imaging Trials, Carl E. Ravin Advanced Imaging Laboratories, Department of Radiology, Duke University School of Medicine, Durham, NC; Department of Electrical & Computer Engineering, Duke University, Durham, NC; Medical Physics Graduate Program, Duke University, Durham, NC; Department of Biomedical Engineering, Duke University, Durham, NC; Department of Physics, Duke University, Durham, NC
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2
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Haase V, Hahn K, Schöndube H, Stierstorfer K, Maier A, Noo F. Single material beam hardening correction via an analytical energy response model for diagnostic CT. Med Phys 2022; 49:5014-5037. [PMID: 35651302 PMCID: PMC9388575 DOI: 10.1002/mp.15787] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Various clinical studies show the potential for a wider quantitative role of diagnostic X-ray computed tomography (CT) beyond size measurements. Currently, the clinical use of attenuation values is however limited due to their lack of robustness. This issue can be observed even on the same scanner across patient size and positioning. There are different causes for the lack of robustness in the attenuation values; one possible source of error is beam hardening of the X-ray source spectrum. The conventional and well-established approach to address this issue is a calibration-based single material beam hardening correction (BHC) using a water cylinder. PURPOSE We investigate an alternative approach for single material BHC with the aim of producing a more robust result for the attenuation values. The underlying hypothesis of this investigation is that calibration based BHC automatically corrects for scattered radiation in a manner that is sub-optimal in terms of bias as soon as the scanned object strongly deviates from the water cylinder used for calibration. METHODS The approach we propose performs BHC via an analytical energy response model that is embedded into a correction pipeline that efficiently estimates and subtracts scattered radiation in a patient-specific manner prior to BHC. The estimation of scattered radiation is based on minimizing, in average, the squared difference between our corrected data and the vendor-calibrated data. The used energy response model is considering the spectral effects of the detector response and of the pre-filtration of the source spectrum including a beam-shaping bowtie filter. The performance of the correction pipeline is first characterized with computer simulated data. Afterwards, it is tested using real 3-D CT data sets of two different phantoms, with various kV settings and phantom positions, assuming a circular data acquisition. The results are compared in the image domain to those from the scanner. RESULTS For experiments with a water cylinder, the proposed correction pipeline leads to similar results as the vendor. For reconstructions of a QRM liver phantom with extension ring, the proposed correction pipeline achieved a more uniform and stable outcome in the attenuation values of homogeneous materials within the phantom. For example, the root mean squared deviation between centered and off-centered phantom positioning was reduced from 6.6 HU to 1.8 HU in one profile. CONCLUSIONS We have introduced a patient-specific approach for single material BHC in diagnostic CT via the use of an analytical energy response model. This approach shows promising improvements in terms of robustness of attenuation values for large patient sizes. Our results contribute towards improving CT images so as to make CT attenuation values more reliable for use in clinical practice. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Viktor Haase
- Siemens Healthcare GmbH, Siemensstr. 3, Forchheim, 91301, Germany.,Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr. 3, Erlangen, 91058, Germany
| | - Katharina Hahn
- Siemens Healthcare GmbH, Siemensstr. 3, Forchheim, 91301, Germany
| | - Harald Schöndube
- Siemens Healthcare GmbH, Siemensstr. 3, Forchheim, 91301, Germany
| | | | - Andreas Maier
- Pattern Recognition Lab, Department of Computer Science, Friedrich-Alexander-Universität Erlangen-Nürnberg, Martensstr. 3, Erlangen, 91058, Germany
| | - Frédéric Noo
- Department of Radiology and Imaging Sciences, University of Utah, 729 Arapeen Drive, Salt Lake City, Utah, 84108, USA
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3
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Cheng T, Li Y, Pang S, Wan H, Shi G, Cheng Q, Li Q, Pan Z, Huang S. Normal lung attenuation distribution and lung volume on computed tomography in a Chinese population. Int J Chron Obstruct Pulmon Dis 2019; 14:1657-1668. [PMID: 31413560 PMCID: PMC6662163 DOI: 10.2147/copd.s187596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 05/10/2019] [Indexed: 01/17/2023] Open
Abstract
Backgroud and objectives: Although lung attenuation distribution and lung volume on computed tomography (CT) have been widely used in evaluating COPD and interstitial lung disease, there are only a few studies regarding the normal range of these indices, especially in Chinese subjects. We aimed to describe the normal range of lung attenuation distribution and lung volume based on CT. Methods: Subjects with normal lung function and basically normal chest CT findings (derivation group) at Ruijin Hospital, Shanghai (from January 2010 to June 2014) were included according to inclusion and exclusion criteria. The range of the percentage of lung volume occupied by low attenuation areas (LAA%), percentile of the histogram of attenuation values (Perc n), and total lung volume were analyzed. Relationships of these measures with demographic variables were evaluated. Participants who underwent chest CT examination for disease screening and had basically normal CT findings served as an external validation group. Results: The number of subjects in the derivation group and external validation groups were 564 and 1,787, respectively. Mean total lung volumes were 4,468±1,271 mL and 4,668±1,192 mL, and median LAA%(-950 HU) was 0.19 (0.03–0.43) and 0.17 (0.01–0.41), in the derivation and external validation groups, respectively. Reference equations for lung volume and attenuation distribution (LAA% using -1,000–210 HU, Perc 1 to Perc 98) were generated: Lung volume (mL) = -1.015 *10^4+605.3*Sex (1= male, 0= female)+92.61*Height (cm) –12.99*Weight (kg) ±1766; LAA% (-950 HU)=[0.2027+0.05926*Sex (1= male, 0= female) –4.111*10^-3*Weight (kg) +4.924*10^-3*Height (cm) +8.504*10^-4*Age]^7.341–0.05; Upper limit of normal range: [0.2027+0.05926*Sex-4.111*10^-3*Weight+4.924*10^-3*Height+8.504*10^-4*Age+0.1993]^7.341–0.05. Conclusion: This large population-based retrospective study demonstrated the normal range of LAA%, Perc n, and total lung volume measured on CT scans among subjects with normal lung function and CT findings. Reference equations are provided.
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Affiliation(s)
- Ting Cheng
- Department of Respiratory Medicine, Ruijin Hospital North, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Yong Li
- Department of Respiratory Medicine, Ruijin Hospital North, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - Shuai Pang
- Department of Respiratory Medicine, Ruijin Hospital North, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - HuanYing Wan
- Department of Respiratory Medicine, Ruijin Hospital North, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - GuoChao Shi
- Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Department of Respiratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - QiJian Cheng
- Department of Respiratory Medicine, Ruijin Hospital North, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - QingYun Li
- Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Department of Respiratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - ZiLai Pan
- Department of Radiology, Ruijin Hospital North, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
| | - ShaoGuang Huang
- Institute of Respiratory Diseases, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China.,Department of Respiratory Medicine, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, People's Republic of China
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4
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Tao S, Rajendran K, McCollough CH, Leng S. Feasibility of multi-contrast imaging on dual-source photon counting detector (PCD) CT: An initial phantom study. Med Phys 2019; 46:4105-4115. [PMID: 31215659 DOI: 10.1002/mp.13668] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Revised: 05/08/2019] [Accepted: 06/10/2019] [Indexed: 12/16/2022] Open
Abstract
PURPOSE Photon-counting-detector-computed tomography (PCD-CT) allows separation of multiple, simultaneously imaged contrast agents, such as iodine (I), gadolinium (Gd), and bismuth (Bi). However, PCDs suffer from several technical limitations such as charge sharing, K-edge escape, and pulse pile-up, which compromise spectral separation of multi-energy data and degrade multi-contrast imaging performance. The purpose of this work was to determine the performance of a dual-source (DS) PCD-CT relative to a single-source (SS) PCD-CT for the separation of simultaneously imaged I, Gd, and Bi contrast agents. METHODS Phantom experiments were performed using a research whole-body PCD-CT and head/abdomen-sized phantoms containing vials of different I, Gd, Bi concentrations. To emulate a DS-PCD-CT, the phantoms were scanned twice on the SS-PCD-CT using different tube potentials for each scan. A tube potential of 80 kV (energy thresholds = 25/50 keV) was used for low-energy tube, while the high-energy tube used Sn140 kV (Sn indicates tin filter) and thresholds of 25/90 keV. The same phantoms were scanned also on the SS-PCD-CT using the chess acquisition mode. In chess mode, the 4 × 4 subpixels within a macro detector pixel are split into two sets based on a chess-board pattern. With each subpixel set having two energy thresholds, chess mode allows four energy-bin data sets, which permits simultaneous multi-contrast imaging. Because of this design, only 50% area of each detector pixel is configured to receive photons of a pre-defined threshold, leading to 50% dose utilization efficiency. To compensate for this dose inefficiency, the radiation dose for this scan was doubled compared to DS-PCD-CT. A 140 kV tube potential and thresholds = 25/50/75/90 keV were used. These settings were determined based on the K-edges of Gd, and Bi, and were found to yield good differentiation of I/Gd/Bi based on phantom experiments and other literature. The energy-bin images obtained from each scan (scan pair) were used to generate I-, Gd-, Bi-specific image via material decomposition. Root-mean-square-error (RMSE) between the known and measured concentrations was calculated for each scenario. A 20-cm water cylinder phantom was scanned on both systems, which was used for evaluating the magnitude of noise, and noise power spectra (NPS) of I/Gd/Bi-specific images. RESULTS Phantom results showed that DS-PCD-CT reduced noise in material-specific images for both head and body phantoms compared to SS-PCD-CT. The noise level of SS-PCD was reduced from 2.55 to 0.90 mg/mL (I), 1.97 to 0.78 mg/mL (Gd), and 0.85 to 0.74 mg/mL (Bi) using DS-PCD. NPS analysis showed that the noise texture of images acquired on both systems is similar. For the body phantom, the RMSE for SS-PCD-CT was reduced relative to DS-PCD-CT from 10.52 to 2.76 mg/mL (I), 7.90 to 2.01 mg/mL (Gd), and 1.91 to 1.16 mg/mL (Bi). A similar trend was observed for the head phantom: RMSE reduced from 2.59 (SS-PCD) to 0.72 (DS-PCD) mg/mL (I), 2.02 to 0.58 mg/mL (Gd), and 0.85 to 0.57 mg/mL (Bi). CONCLUSION We demonstrate the feasibility of performing simultaneous imaging of I, Gd, and Bi materials on DS-PCD-CT. Under the condition without cross scattering, DS-PCD reduced the RMSE for quantification of material concentration in relative to a SS-PCD-CT system using chess mode.
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Affiliation(s)
- Shengzhen Tao
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | | | - Shuai Leng
- Department of Radiology, Mayo Clinic, Rochester, MN, USA
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5
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Sieren JP, Newell JD, Barr RG, Bleecker ER, Burnette N, Carretta EE, Couper D, Goldin J, Guo J, Han MK, Hansel NN, Kanner RE, Kazerooni EA, Martinez FJ, Rennard S, Woodruff PG, Hoffman EA. SPIROMICS Protocol for Multicenter Quantitative Computed Tomography to Phenotype the Lungs. Am J Respir Crit Care Med 2018; 194:794-806. [PMID: 27482984 DOI: 10.1164/rccm.201506-1208pp] [Citation(s) in RCA: 168] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Multidetector row computed tomography (MDCT) is increasingly taking a central role in identifying subphenotypes within chronic obstructive pulmonary disease (COPD), asthma, and other lung-related disease populations, allowing for the quantification of the amount and distribution of altered parenchyma along with the characterization of airway and vascular anatomy. The embedding of quantitative CT (QCT) into a multicenter trial with a variety of scanner makes and models along with the variety of pressures within a clinical radiology setting has proven challenging, especially in the context of a longitudinal study. SPIROMICS (Subpopulations and Intermediate Outcome Measures in COPD Study), sponsored by the National Institutes of Health, has established a QCT lung assessment system (QCT-LAS), which includes scanner-specific imaging protocols for lung assessment at total lung capacity and residual volume. Also included are monthly scanning of a standardized test object and web-based tools for subject registration, protocol assignment, and data transmission coupled with automated image interrogation to assure protocol adherence. The SPIROMICS QCT-LAS has been adopted and contributed to by a growing number of other multicenter studies in which imaging is embedded. The key components of the SPIROMICS QCT-LAS along with evidence of implementation success are described herein. While imaging technologies continue to evolve, the required components of a QCT-LAS provide the framework for future studies, and the QCT results emanating from SPIROMICS and the growing number of other studies using the SPIROMICS QCT-LAS will provide a shared resource of image-derived pulmonary metrics.
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Affiliation(s)
- Jered P Sieren
- 1 Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - John D Newell
- 1 Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - R Graham Barr
- 2 Department of Medicine and Department of Epidemiology, Columbia University College of Medicine, New York, New York
| | - Eugene R Bleecker
- 3 Center for Human Genomics and Personalized Medicine, Wake Forest University Health Sciences, Winston-Salem, North Carolina
| | - Nathan Burnette
- 1 Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Elizabeth E Carretta
- 4 Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
| | - David Couper
- 4 Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina
| | - Jonathan Goldin
- 5 Department of Radiology, University of California Los Angeles, Los Angeles, California
| | - Junfeng Guo
- 1 Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | | | - Nadia N Hansel
- 7 Department of Medicine, The Johns Hopkins University, Baltimore, Maryland
| | - Richard E Kanner
- 8 Department of Internal Medicine, University of Utah, Salt Lake City, Utah
| | - Ella A Kazerooni
- 9 Department of Radiology, University of Michigan Medical School, Ann Arbor, Michigan
| | - Fernando J Martinez
- 10 Department of Medicine, Weill Cornell Medical College, New York, New York
| | - Stephen Rennard
- 11 Department of Internal Medicine, University of Nebraska, Omaha, Nebraska; and
| | - Prescott G Woodruff
- 12 Department of Medicine, University of California San Francisco, San Francisco, California
| | - Eric A Hoffman
- 1 Department of Radiology, University of Iowa Carver College of Medicine, Iowa City, Iowa
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Yu J, He Y, Hao J, Liu F, Li H, Wang C, Wang H. A mathematical model to characterize the degree of coalification based on the low-angle region of the X-ray diffractogram. JOURNAL OF X-RAY SCIENCE AND TECHNOLOGY 2018; 26:71-81. [PMID: 28854529 DOI: 10.3233/xst-17277] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Based on X-ray diffraction (XRD) pattern of coal, an empirical model for judging the coalification degree is used to calculate the ratio of the 002 peak height to the Full width at half maximum (FWHM). However, the existing models are often simpler and more suitable for judgment of the medium and low rank coal, while are not feasible in determination of high rank coal. In order to address this issue, the objective of this study is to establish a new modified mathematical model based on optimization of the existing empirical models. Through the calculation of Bragg equation, it demonstrates that the low-angle region (2θ= 3-10°) in the XRD pattern reflects the information of micropore in coal with a diameter of (0.884-2.94) nm. Accordingly, its diffraction intensity corresponds to the porosity rate in coal. As a result, the modified mathematical model has been established for characterizing the coalification degree by introducing the variation of porosity rate with the coal ranks creatively. The synergistic effects of the change regulation of organic matter peak and the porosity rate with coal rank ensure the accuracy of the model. Furthermore, the good stability and high reliability of new model are verified through the recalculation of a total of 14 coal samples. Study results demonstrated that the new method enabled to determine coal rank more conveniently and accurately in the industrial production.
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Affiliation(s)
- Jiadong Yu
- Key Laboratory of Coal Processing and Efficient Utilization, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Yaqun He
- Key Laboratory of Coal Processing and Efficient Utilization, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
- Advanced Analysis and Computation Center, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Juan Hao
- Key Laboratory of Coal Processing and Efficient Utilization, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Fengyongzheng Liu
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Hong Li
- Key Laboratory of Coal Processing and Efficient Utilization, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Chao Wang
- Advanced Analysis and Computation Center, China University of Mining and Technology, Xuzhou, Jiangsu, China
| | - Haifeng Wang
- Key Laboratory of Coal Processing and Efficient Utilization, China University of Mining and Technology, Xuzhou, Jiangsu, China
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou, Jiangsu, China
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7
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Santos A, Rivas E, Rodríguez-Roisin R, Sánchez M, Ruiz-Cabello J, Arismendi E, Venegas JG. Lung Tissue Volume is Elevated in Obesity and Reduced by Bariatric Surgery. Obes Surg 2017; 26:2475-82. [PMID: 27000884 DOI: 10.1007/s11695-016-2137-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
BACKGROUND Bariatric surgery (BS) in severely obese subjects causes a significant reduction of body weight with lung function improvement. We have shown that abnormalities in pulmonary gas exchange in morbidly obese subjects are substantially improved with BS. These abnormalities were thought to be related to reduced lung volumes as well as to abnormal endothelial function induced by low-grade chronic inflammation linked to perivascular adipose tissue (PVAT). In this study, we used computed tomography (CT) to assess whether BS also caused measurable structural changes in the lung tissue volume (Vtiss) and cross-sectional vessel analysis, hypothesizing that these measures could be related to the previously reported lung functional changes. METHODS This is a post hoc analysis of a previous reported prospective study. Pulmonary vessels and lung volumes, including Vtiss, were quantified in thoracic CT scans. We compared findings in 12 obese women before and after BS and in 8 healthy lean women. RESULTS Vtiss was significantly elevated in obese subjects before BS compared to control subjects and systematically reduced after BS (by 8 %); other CT lung volumes or vascular areas were not affected in a consistent manner. No relationship was observed between BS-induced individual changes in Vtiss and pulmonary vessel area. CONCLUSIONS Vtiss is elevated in morbidly obese subjects, compared to lean individuals of similar body height, and is systematically reduced by BS. These effects do not appear related to vascular changes but may be caused by elevated extravascular lung water, due to low-grade inflammation, and/or hypertrophic PVAT in severe obesity.
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Affiliation(s)
- Arnoldo Santos
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.,Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain
| | - Eva Rivas
- Servei d'Anestesiologia, Hospital Clínic, Barcelona, Spain.,Institut d'investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Fundació Clínic per a la Recerca Biomédica (FCRB), Barcelona, Spain
| | - Roberto Rodríguez-Roisin
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain. .,Institut d'investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Fundació Clínic per a la Recerca Biomédica (FCRB), Barcelona, Spain. .,Servei de Pneumologia, Institut Clínic Respiratori, Hospital Clínic, Barcelona, Spain.
| | - Marcelo Sánchez
- Centre de Diagnòstic per la Imatge (CDI), Hospital Clínic, Barcelona, Spain
| | - Jesús Ruiz-Cabello
- Centro Nacional de Investigaciones Cardiovasculares Carlos III (CNIC), Madrid, Spain.,CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain.,Universidad Complutense de Madrid (UCM), Madrid, Spain
| | - Ebymar Arismendi
- CIBER de Enfermedades Respiratorias (CIBERES), Madrid, Spain.,Institut d'investigacions Biomèdiques August Pi i Sunyer (IDIBAPS) and Fundació Clínic per a la Recerca Biomédica (FCRB), Barcelona, Spain
| | - José G Venegas
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
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8
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Michalak G, Taasti V, Krauss B, Deisher A, Halaweish A, McCollough C. A comparison of relative proton stopping power measurements across patient size using dual- and single-energy CT. Acta Oncol 2017; 56:1465-1471. [PMID: 28885130 DOI: 10.1080/0284186x.2017.1372625] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
PURPOSE To evaluate the accuracy and precision across phantom size of a dual-energy computed tomography (DECT) technique used to calculate relative proton stopping power (SPR) in tissue-simulating materials and a silicone implant relative to conventional single-energy CT (SECT). MATERIAL AND METHODS A 32 cm lateral diameter (CIRS model 062M, Norfolk, Virginia) electron density phantom containing inserts which simulated the chemical composition of eight tissues in a solid-water background was scanned using SECT and DECT. A liquid water insert was included to confirm CT number accuracy. All materials were also placed in four water tanks, ranging from 15 to 45 cm in lateral width and scanned using DECT and SECT. A silicone breast implant was scanned in the same water phantoms. SPR values were calculated based on commercial software (syngo CT Dual Energy, Siemens Healthcare GmbH) and compared to reference values derived from proton beam measurements. Accuracy and precision were quantified across phantom size using percent error and standard deviation. Graphical and regression analysis were used to determine whether SECT or DECT was superior in estimating SPR across phantom size. RESULTS Both DECT and SECT SPR data resulted in good agreement with the reference values. Percent error was ±3% for both DECT and SECT in all materials except lung and dense bone. The coefficient of variation (CV) across materials and phantom sizes was 1.12% for SECT and 0.96% for DECT. Material-specific regression and graphical analysis did not reveal size dependence for either technique but did show reduced systematic bias with DECT for dense bone and liver. Mean percent error in SPR for the implant was reduced from 11.46% for SECT to 0.49% for DECT. CONCLUSIONS We demonstrate the superior ability of DECT to mitigate systematic bias in bones and liver and estimate SPR in a silicone breast implant.
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Affiliation(s)
| | - Vicki Taasti
- Department of Medical Physics, Aarhus University Hospital, Aarhus, Denmark
| | | | - Amanda Deisher
- Department of Radiation Oncology, Mayo Clinic, Rochester, MN, USA
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9
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Boueiz A, Chang Y, Cho MH, Washko GR, San José Estépar R, Bowler RP, Crapo JD, DeMeo DL, Dy JG, Silverman EK, Castaldi PJ. Lobar Emphysema Distribution Is Associated With 5-Year Radiological Disease Progression. Chest 2017; 153:65-76. [PMID: 28943279 DOI: 10.1016/j.chest.2017.09.022] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Revised: 07/13/2017] [Accepted: 09/06/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Emphysema has considerable variability in its regional distribution. Craniocaudal emphysema distribution is an important predictor of the response to lung volume reduction. However, there is little consensus regarding how to define upper lobe-predominant and lower lobe-predominant emphysema subtypes. Consequently, the clinical and genetic associations with these subtypes are poorly characterized. METHODS We sought to identify subgroups characterized by upper-lobe or lower-lobe emphysema predominance and comparable amounts of total emphysema by analyzing data from 9,210 smokers without alpha-1-antitrypsin deficiency in the Genetic Epidemiology of COPD (COPDGene) cohort. CT densitometric emphysema was measured in each lung lobe. Random forest clustering was applied to lobar emphysema variables after regressing out the effects of total emphysema. Clusters were tested for association with clinical and imaging outcomes at baseline and at 5-year follow-up. Their associations with genetic variants were also compared. RESULTS Three clusters were identified: minimal emphysema (n = 1,312), upper lobe-predominant emphysema (n = 905), and lower lobe-predominant emphysema (n = 796). Despite a similar amount of total emphysema, the lower-lobe group had more severe airflow obstruction at baseline and higher rates of metabolic syndrome compared with subjects with upper-lobe predominance. The group with upper-lobe predominance had greater 5-year progression of emphysema, gas trapping, and dyspnea. Differential associations with known COPD genetic risk variants were noted. CONCLUSIONS Subgroups of smokers defined by upper-lobe or lower-lobe emphysema predominance exhibit different functional and radiological disease progression rates, and the upper-lobe predominant subtype shows evidence of association with known COPD genetic risk variants. These subgroups may be useful in the development of personalized treatments for COPD.
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Affiliation(s)
- Adel Boueiz
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Yale Chang
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA
| | - Michael H Cho
- Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - George R Washko
- Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Raul San José Estépar
- Surgical Planning Laboratory, Laboratory of Mathematics in Imaging, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Russell P Bowler
- Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, CO
| | - James D Crapo
- Division of Pulmonary Medicine, Department of Medicine, National Jewish Health, Denver, CO
| | - Dawn L DeMeo
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Jennifer G Dy
- Department of Electrical and Computer Engineering, Northeastern University, Boston, MA
| | - Edwin K Silverman
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Pulmonary and Critical Care Medicine Division, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Peter J Castaldi
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA; Division of General Medicine and Primary Care, Brigham and Women's Hospital, Harvard Medical School, Boston, MA.
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10
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Hoffman EA, Newell JD. Lung Mass as the Complement to Lung Air Content in Quantitative CT of the COPD Lung. Acad Radiol 2017; 24:383-385. [PMID: 28262202 DOI: 10.1016/j.acra.2017.01.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Accepted: 01/31/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Eric A Hoffman
- Department of Radiology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52240; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa.
| | - John D Newell
- Department of Radiology, University of Iowa, 200 Hawkins Drive, Iowa City, IA 52240; Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa
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11
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Hwang HJ, Hoffman EA, Lee CH, Goo JM, Levin DL, Kauczor HU, Seo JB. The role of dual-energy computed tomography in the assessment of pulmonary function. Eur J Radiol 2016; 86:320-334. [PMID: 27865580 DOI: 10.1016/j.ejrad.2016.11.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 11/02/2016] [Accepted: 11/04/2016] [Indexed: 01/05/2023]
Abstract
The assessment of pulmonary function, including ventilation and perfusion status, is important in addition to the evaluation of structural changes of the lung parenchyma in various pulmonary diseases. The dual-energy computed tomography (DECT) technique can provide the pulmonary functional information and high resolution anatomic information simultaneously. The application of DECT for the evaluation of pulmonary function has been investigated in various pulmonary diseases, such as pulmonary embolism, asthma and chronic obstructive lung disease and so on. In this review article, we will present principles and technical aspects of DECT, along with clinical applications for the assessment pulmonary function in various lung diseases.
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Affiliation(s)
- Hye Jeon Hwang
- Department of Radiology, Hallym University College of Medicine, Hallym University Sacred Heart Hospital, 22, Gwanpyeong-ro 170beon-gil, Dongan-gu, Anyang-si, Gyeonggi-do 431-796, Republic of Korea
| | - Eric A Hoffman
- Departments of Radiology, Medicine, and Biomedical Engineering, University of Iowa, 200 Hawkins Dr, CC 701 GH, Iowa City, IA 52241, United States
| | - Chang Hyun Lee
- Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799, Republic of Korea
| | - Jin Mo Goo
- Department of Radiology, Seoul National University College of Medicine, 103 Daehak-ro, Jongno-gu, Seoul 110-799, Republic of Korea
| | - David L Levin
- Department of Radiology, Mayo Clinic College of Medicine, 200 First Street, SW, Rochester, MN 55905, United States
| | - Hans-Ulrich Kauczor
- Diagnostic and Interventional Radiology, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany; Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Joon Beom Seo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, 388-1, Pungnap 2-dong, Songpa-ku, Seoul, 05505, Republic of Korea.
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12
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Hammond E, Newell JD, Dilger SKN, Stoyles N, Morgan J, Sieren JP, Thedens DR, Hoffman EA, Meyerholz DK, Sieren JC. Computed Tomography and Magnetic Resonance Imaging for Longitudinal Characterization of Lung Structure Changes in a Yucatan Miniature Pig Silicosis Model. Toxicol Pathol 2016; 44:373-81. [PMID: 26839326 DOI: 10.1177/0192623315622303] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Medical imaging is a rapidly advancing field enabling the repeated, noninvasive assessment of physiological structure and function. These beneficial characteristics can supplement studies in swine by mirroring the clinical functions of detection, diagnosis, and monitoring in humans. In addition, swine may serve as a human surrogate, facilitating the development and comparison of new imaging protocols for translation to humans. This study presents methods for pulmonary imaging developed for monitoring pulmonary disease initiation and progression in a pig exposure model with computed tomography and magnetic resonance imaging. In particular, a focus was placed on systematic processes, including positioning, image acquisition, and structured reporting to monitor longitudinal change. The image-based monitoring procedure was applied to 6 Yucatan miniature pigs. A subset of animals (n= 3) were injected with crystalline silica into the apical bronchial tree to induce silicosis. The methodology provided longitudinal monitoring and evidence of progressive lung disease while simultaneously allowing for a cross-modality comparative study highlighting the practical application of medical image data collection in swine. The integration of multimodality imaging with structured reporting allows for cross comparison of modalities, refinement of CT and MRI protocols, and consistently monitors potential areas of interest for guided biopsy and/or necropsy.
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Affiliation(s)
- Emily Hammond
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - John D Newell
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Samantha K N Dilger
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - Nicholas Stoyles
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - John Morgan
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - Jered P Sieren
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - Daniel R Thedens
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
| | - Eric A Hoffman
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | | | - Jessica C Sieren
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
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13
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Variation in the percent of emphysema-like lung in a healthy, nonsmoking multiethnic sample. The MESA lung study. Ann Am Thorac Soc 2015; 11:898-907. [PMID: 24983825 DOI: 10.1513/annalsats.201310-364oc] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RATIONALE Computed tomography (CT)-based lung density is used to quantitate the percentage of emphysema-like lung (hereafter referred to as percent emphysema), but information on its distribution among healthy nonsmokers is limited. OBJECTIVES We evaluated percent emphysema and total lung volume on CT scans of healthy never-smokers in a multiethnic, population-based study. METHODS The Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study investigators acquired full-lung CT scans of 3,137 participants (ages 54-93 yr) between 2010-12. The CT scans were taken at full inspiration following the Subpopulations and Intermediate Outcome Measures in COPD Study (SPIROMICS) protocol. "Healthy never-smokers" were defined as participants without a history of tobacco smoking or respiratory symptoms and disease. "Percent emphysema" was defined as the percentage of lung voxels below -950 Hounsfield units. "Total lung volume" was defined by the volume of lung voxels. MEASUREMENTS AND MAIN RESULTS Among 854 healthy never-smokers, the median percent emphysema visualized on full-lung scans was 1.1% (interquartile range, 0.5-2.5%). The percent emphysema values were 1.2 percentage points higher among men compared with women and 0.7, 1.2, and 1.2 percentage points lower among African Americans, Hispanics, and Asians compared with whites, respectively (P < 0.001). Percent emphysema was positively related to age and height and inversely related to body mass index. The findings were similar for total lung volume on CT scans and for percent emphysema defined at -910 Hounsfield units and measured on cardiac scans. Reference equations to account for these differences are presented for never, former and current smokers. CONCLUSIONS Similar to lung function, percent emphysema varies substantially by demographic factors and body size among healthy never-smokers. The presented reference equations will assist in defining abnormal values for percent emphysema and total lung volume on CT scans, although validation is pending.
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14
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Choi S, Hoffman EA, Wenzel SE, Castro M, Lin CL. Improved CT-based estimate of pulmonary gas trapping accounting for scanner and lung-volume variations in a multicenter asthmatic study. J Appl Physiol (1985) 2014; 117:593-603. [PMID: 25103972 DOI: 10.1152/japplphysiol.00280.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Lung air trapping is estimated via quantitative computed tomography (CT) using density threshold-based measures on an expiration scan. However, the effects of scanner differences and imaging protocol adherence on quantitative assessment are known to be problematic. This study investigates the effects of protocol differences, such as using different CT scanners and breath-hold coaches in a multicenter asthmatic study, and proposes new methods that can adjust intersite and intersubject variations. CT images of 50 healthy subjects and 42 nonsevere and 52 severe asthmatics at total lung capacity (TLC) and functional residual capacity (FRC) were acquired using three different scanners and two different coaching methods at three institutions. A fraction threshold-based approach based on the corrected Hounsfield unit of air with tracheal density was applied to quantify air trapping at FRC. The new air-trapping method was enhanced by adding a lung-shaped metric at TLC and the lobar ratio of air-volume change between TLC and FRC. The fraction-based air-trapping method is able to collapse air-trapping data of respective populations into distinct regression lines. Relative to a constant value-based clustering scheme, the slope-based clustering scheme shows the improved performance and reduced misclassification rate of healthy subjects. Furthermore, both lung shape and air-volume change are found to be discriminant variables for differentiating among three populations of healthy subjects and nonsevere and severe asthmatics. In conjunction with the lung shape and air-volume change, the fraction-based measure of air trapping enables differentiation of severe asthmatics from nonsevere asthmatics and nonsevere asthmatics from healthy subjects, critical for the development and evaluation of new therapeutic interventions.
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Affiliation(s)
- Sanghun Choi
- Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, Iowa; IIHR-Hydroscience & Engineering, The University of Iowa, Iowa City, Iowa; Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa
| | - Eric A Hoffman
- Department of Biomedical Engineering, The University of Iowa, Iowa City, Iowa; Department of Radiology, The University of Iowa, Iowa City, Iowa; Department of Internal Medicine, The University of Iowa, Iowa City, Iowa
| | - Sally E Wenzel
- Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh Pennsylvania; and
| | - Mario Castro
- Departments of Internal Medicine and Pediatrics, Washington University School of Medicine, St. Louis, Missouri
| | - Ching-Long Lin
- Department of Mechanical and Industrial Engineering, The University of Iowa, Iowa City, Iowa; IIHR-Hydroscience & Engineering, The University of Iowa, Iowa City, Iowa;
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