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Elbehairy AF, Marshall H, Naish JH, Wild JM, Parraga G, Horsley A, Vestbo J. Advances in COPD imaging using CT and MRI: linkage with lung physiology and clinical outcomes. Eur Respir J 2024; 63:2301010. [PMID: 38548292 DOI: 10.1183/13993003.01010-2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 03/16/2024] [Indexed: 05/04/2024]
Abstract
Recent years have witnessed major advances in lung imaging in patients with COPD. These include significant refinements in images obtained by computed tomography (CT) scans together with the introduction of new techniques and software that aim for obtaining the best image whilst using the lowest possible radiation dose. Magnetic resonance imaging (MRI) has also emerged as a useful radiation-free tool in assessing structural and more importantly functional derangements in patients with well-established COPD and smokers without COPD, even before the existence of overt changes in resting physiological lung function tests. Together, CT and MRI now allow objective quantification and assessment of structural changes within the airways, lung parenchyma and pulmonary vessels. Furthermore, CT and MRI can now provide objective assessments of regional lung ventilation and perfusion, and multinuclear MRI provides further insight into gas exchange; this can help in structured decisions regarding treatment plans. These advances in chest imaging techniques have brought new insights into our understanding of disease pathophysiology and characterising different disease phenotypes. The present review discusses, in detail, the advances in lung imaging in patients with COPD and how structural and functional imaging are linked with common resting physiological tests and important clinical outcomes.
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Affiliation(s)
- Amany F Elbehairy
- Department of Chest Diseases, Faculty of Medicine, Alexandria University, Alexandria, Egypt
- Division of Infection, Immunity and Respiratory Medicine, The University of Manchester and Manchester University NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK
| | - Helen Marshall
- POLARIS, Imaging, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
| | - Josephine H Naish
- MCMR, Manchester University NHS Foundation Trust, Manchester, UK
- Bioxydyn Limited, Manchester, UK
| | - Jim M Wild
- POLARIS, Imaging, Department of Infection, Immunity and Cardiovascular Disease, University of Sheffield, Sheffield, UK
- Insigneo Institute for in silico Medicine, Sheffield, UK
| | - Grace Parraga
- Robarts Research Institute, Western University, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
- Division of Respirology, Western University, London, ON, Canada
| | - Alexander Horsley
- Division of Infection, Immunity and Respiratory Medicine, The University of Manchester and Manchester University NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK
| | - Jørgen Vestbo
- Division of Infection, Immunity and Respiratory Medicine, The University of Manchester and Manchester University NHS Foundation Trust, Manchester Academic Health Sciences Centre, Manchester, UK
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Tanguay J, Basharat F. Xenon-enhanced dual-energy tomosynthesis for functional imaging of respiratory disease-Concept and phantom study. Med Phys 2023; 50:719-736. [PMID: 36419344 DOI: 10.1002/mp.16101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 10/21/2022] [Accepted: 10/23/2022] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND Xenon-enhanced dual-energy (DE) computed tomography (CT) and hyperpolarized noble-gas magnetic resonance imaging (MRI) provide maps of lung ventilation that can be used to detect chronic obstructive pulmonary disease (COPD) early in its development and predict respiratory exacerbations. However, xenon-enhanced DE-CT requires high radiation doses and hyper-polarized noble-gas MRI is expensive and only available at a handful of institutions globally. PURPOSE To present xenon-enhanced dual-energy tomosynthesis (XeDET) for low-dose, low-cost functional imaging of respiratory disease in an experimental phantom study. METHODS We propose using digital tomosynthesis to produce Xe-enhanced low-energy (LE) and high-energy (HE) coronal images. DE subtraction of the LE and HE images is used to suppress soft tissues. We used an imaging phantom to investigate image quality in terms of the area under the reciever operating characteristic curve (AUC) for the Non-PreWhitening model observer with an Eye filter and internal noise (NPWEi). The phantom simulated anatomic clutter due to lung parenchyma and attenuation due to soft tissue and lung tissue. Aluminum slats were used to simulate rib structures. A stepwedge consisting of an acrylic casing with sealed cylindrical air-filled cavities was used to simulate ventilation defects with step thicknesses of 0.5, 1, and 2 cm and cylindrical radii of 0.5, 0.75, and 1 cm. The phantom was ventilated with Xe and projection data were acquired using a flat-panel detector, a tube-voltage combination of 60/140 kV with 1.2 mm of copper filtration on the HE spectrum and an angular range of ± 15 ∘ $\pm 15^{\circ}$ in 1° increments. The AUC of a NPWEi observer that has access only to a single coronal slice was calculated from measurements of the three-dimensional noise power spectrum and signal template. The AUC was calculated as a function of ventilation defect thickness and radius for total patient entrance air kermas ranging from 1.42 to 2.84 mGy with and without rib-simulating Al slats. For the AUC analysis, the observer internal noise level was obtained from an ad hoc calibration to a high-dose data set. RESULTS XeDET was able to suppress parenchyma-simulating clutter in coronal images enabling visualization of the simulated ventilation defects, but the limited angle acquisition resulted in residual clutter due to out-of-plane bone-mimmicking structures. The signal power of the defects increased linearly with defect radius and showed a ten-fold to fifteen-fold increase in signal power when the defect thickness increased from 0.5 to 2 cm. These trends agreed with theoretical predictions. Along the depth dimension, the power of the defects decreased exponentially with distance from the center of the defects with full-width half maxima that varied from 1.85 to 2.85 cm depending on the defect thickness and radius. The AUCs of the 1-cm-radius defect that was 2 cm in thickness ranged from good (0.8-0.9) to excellent (0.9-1.0) over the range of air kermas considered. CONCLUSIONS Xenon-enhanced DE tomosynthesis has the potential to enable functional imaging of respiratory disease and should be further investigated as a low-cost alternative to MRI-based approaches and a low-dose alternative to CT-based approaches.
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Affiliation(s)
- Jesse Tanguay
- Department of Physics, Toronto Metropoliton University (formerly Ryerson University), Toronto, ON, Canada
| | - Fateen Basharat
- Department of Physics, Toronto Metropoliton University (formerly Ryerson University), Toronto, ON, Canada
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Basharat F, Tanguay J. Experimental feasibility of xenon-enhanced dual-energy radiography for imaging of lung function. Phys Med Biol 2022; 67. [PMID: 36395522 DOI: 10.1088/1361-6560/aca3f8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 11/17/2022] [Indexed: 11/19/2022]
Abstract
Chronic obstructive pulmonary disease (COPD) is a leading cause of death worldwide. We experimentally investigated the feasibility of two-dimensional xenon-enhanced dual-energy (XeDE) radiography for imaging of lung function. We optimized image quality under quantum-noise-limited conditions using a chest phantom consisting of a rectangular chamber representing the thoracic volume and PMMA slabs simulating x-ray attenuation by soft tissue. A sealed, air-filled cavity with thin PMMA walls was positioned inside the chamber to simulate a 2 cm thick ventilation defect. The chamber was ventilated with xenon and dual-energy imaging was performed using a diagnostic x-ray tube and a flat-panel detector. The contrast-to-noise ratio of ventilation defects normalized by patient x-ray exposure maximized at a kV-pair of approximately 60/140-kV and when approximately one third of the total exposure was allocated to the HE image. We used the optimized technique to image a second phantom that contained lung-parenchyma-mimicking PMMA clutter, rib-mimicking aluminum slats and an insert that simulated ventilation defects with thicknesses ranging from 0.5 cm to 2 cm and diameters ranging from 1 cm to 2 cm. From the resulting images we computed the area under the receiver operating characteristic curve (AUC) of the non-prewhitening model observer with an eye filter and internal noise. For a xenon concentration of 75%, good AUCs (i.e. 0.8-0.9) to excellent AUCs (i.e. >0.9) were obtained when the defect diameter is greater than 1.3 cm and defect thickness is 1 cm. When the xenon concentration was reduced to 50%, the AUC was ∼0.9 for defects 1.2 cm in diameter and ∼1.5 cm in thickness. Two-dimensional XeDE radiography may therefore enable detection of functional abnormalities associated with early-stage COPD, for which xenon ventilation defects can occupy up to 20% of the lung volume, and should be further developed as a low-cost alternative to MRI-based approaches and a low-dose alternative to CT-based approaches.
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Affiliation(s)
- Fateen Basharat
- Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada
| | - Jesse Tanguay
- Department of Physics, Toronto Metropolitan University, Toronto, ON, Canada
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Comparison of Radiation Dose and Image Quality Between Split-Filter Twin Beam Dual-Energy Images and Single-Energy Images in Single-Source Contrast-Enhanced Chest Computed Tomography. J Comput Assist Tomogr 2021; 45:888-893. [PMID: 34469908 DOI: 10.1097/rct.0000000000001220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To compare image quality and radiation dose of split-filter TwinBeam dual-energy (SF-TBDE) with those of single-energy images (SECT) in the contrast-enhanced chest computed tomography (CT). METHODS Two hundred patients who underwent SF-TBDE (n = 100) and SECT (n = 100) contrast-enhanced chest scanning were retrospectively analyzed. The contrast-to-noise ratio (CNR) and figure of merit (FOM)-CNR of 5 structures (lung, aorta, pulmonary artery, thyroid, and erector spinae) were calculated and subjectively evaluated by 2 independent radiologists. Radiation dose was compared using volume CT dose index and size-specific dose estimate. RESULTS The CNR and FOM-CNR of lung and erector spinae in SF-TBDE were higher than those of SECT (P < 0.001). The differences in the subjective image quality between the 2 groups were not significant (P = 0.244). Volume CT dose index and size-specific dose estimate of SF-TBDE were lower than those of SECT (6.60 ± 1.56 vs 7.81 ± 3.02 mGy, P = 0.001; 9.25 ± 1.60 vs. 10.55 ± 3.54; P = 0.001). CONCLUSIONS The SF-TBDE CT can provide similar image quality at a lower radiation dose compared with SECT.
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Lim JU, Lee JS, Lee JH, Lee SD, Oh YM, Rhee CK. Clinical impact of long-term change in air trapping on pulmonary function and computed tomography parameters in chronic obstructive pulmonary disease. Korean J Intern Med 2021; 36:636-646. [PMID: 33232591 PMCID: PMC8137389 DOI: 10.3904/kjim.2019.425] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Accepted: 03/27/2020] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND/AIMS Air trapping is associated with unfavorable outcomes in chronic obstructive pulmonary disease (COPD). The present study evaluated the association between longitudinal changes in air trapping with pulmonary function, computed tomography (CT) parameters and exacerbation. METHODS Patients enrolled in the Korean Obstructive Lung Disease (KOLD) study cohort from June 2005 to October 2015 were included. The study patients were categorized into four groups according to the change in residual volume to total lung capacity ratio (RV/TLC) over 3 years. The RV/TLC was considered abnormal when it was ≥ 40% and normal when it was < 40%. RESULTS A total of 279 patients were categorized into four groups: 76 in the "normal to normal" (N→N) group, 34 in the "abnormal to normal" (A→N) group, 33 in the "normal to abnormal" (N→A) group, and 136 in the "abnormal to abnormal" (A→A) group. For forced expiratory volume in 1 second and forced vital capacity (FVC), respectively, group A→N showed a large increase of 266 mL (p < 0.001) and 381 mL (p < 0.001), group N→A showed a marked decrease of 216 mL (p < 0.001) and 332 mL(p = 0.029), and group A→A showed a decrease of 16 mL (p = 0.426) and 6 mL (p = 0.011) compared to group N→N. Group A→N showed a significant decrease of -0.013 in expiratory to inspiratory ratio of the mean lung density (p < 0.001), while group A→N showed an increase of 0.005 (p < 0.001). CONCLUSION Patients with COPD whose RV/TLC changed from normal to abnormal showed deterioration of pulmonary function and worsening of CT parameters simultaneously.
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Affiliation(s)
- Jeong Uk Lim
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul,
Korea
| | - Jae Seung Lee
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Ji-Hyun Lee
- Department of Internal Medicine, Bundang CHA Medical Center, CHA University College of Medicine, Seongnam,
Korea
| | - Sang-Do Lee
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Yeon-Mok Oh
- Department of Pulmonary and Critical Care Medicine, Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine, Seoul,
Korea
| | - Chin Kook Rhee
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul,
Korea
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Ohno Y, Fujisawa Y, Yoshikawa T, Takenaka D, Koyama H, Hattori H, Murayama K, Fujii K, Sugihara N, Toyama H. Inspiratory/expiratory xenon-enhanced area-detector CT: Capability for quantitative assessment of lung ventilation changes in surgically treated non-small cell lung cancer patients. Eur J Radiol 2021; 136:109574. [PMID: 33548852 DOI: 10.1016/j.ejrad.2021.109574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 01/22/2021] [Accepted: 01/24/2021] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate the capability of inspiratory/expiratory Xe-enhanced ADCT for assessment of changes in pulmonary function and regional ventilation of surgically treated NSCLC patients. METHOD AND MATERIALS Forty consecutive surgically treated NSCLC patients underwent pre- and postoperative inspiratory/expiratory Xe-enhanced ADCT and pulmonary function tests. For each patient, pre- and post-operative data were analyzed and pre- and post-operative wash-in (WI) and wash-out (WO) indexes and ventilation ratio (VR=[WI-WO]/WI) maps generated by means of pixel-by-pixel analyses. Differences between pre- and postoperative WI (ΔWI), WO (ΔWO) and VR (ΔVR) were also determined. To determine the relationship between all ventilation index changes and pulmonary functional loss, Pearson's correlation was used to correlate each ventilation index change with the corresponding pulmonary functional parameter change. In addition, stepwise regression analysis was performed for all ventilation index changes and each corresponding pulmonary functional parameter change. RESULTS FEV1/FVC% change showed fair or good and significant correlations with ΔWI (r = 0.39, p = 0.01) and ΔVR (r = 0.68, p = 0.001), %FEV1 change good or moderate and significant correlations with ΔWI (r = 0.56, p = 0.0001) and ΔVR (r = 0.76, p < 0.0001), and %VC change moderate yet significant correlation with ΔWI (r = 0.65, p < 0.0001) and ΔVR (r = 0.67, p < 0.0001). Stepwise regression analysis demonstrated that FEV1/FVC% change (r2 = 0.56, p < 0.0001) significantly affected two factors, ΔVR (p < 0.0001) and ΔWI (p = 0.006), as did %FEV1 change (r2 = 0.68, p < 0.0001) [ΔVR (p < 0.0001) and ΔWI (p = 0.0001)], and %VC change (r2 = 0.63, p < 0.0001) [ΔVR (p < 0.0001) and ΔWI (p = 0.0001)]. CONCLUSION Inspiratory/expiratory Xe-enhanced ADCT has the potential to demonstrate that pre- and postoperative ventilation status of surgically treated NSCLC patients correlates with pulmonary function.
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Affiliation(s)
- Yoshiharu Ohno
- Department of Radiology, Fujita Health University School of Medicine, Toyoake, Japan; Joint Laboratory Research of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan; Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan.
| | | | - Takeshi Yoshikawa
- Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan; Department of Radiology, Hyogo Cancer Center, Akashi, Japan
| | | | - Hisanobu Koyama
- Department of Radiology, Osaka Police Hospital, Osaka, Japan
| | - Hidetkazu Hattori
- Department of Radiology, Fujita Health University School of Medicine, Toyoake, Japan
| | - Kazuhiro Murayama
- Joint Laboratory Research of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Japan
| | - Kenji Fujii
- Canon Medical Systems Corporation, Otawara, Japan
| | | | - Hiroshi Toyama
- Department of Radiology, Fujita Health University School of Medicine, Toyoake, Japan
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Kim M, Doganay O, Hwang HJ, Seo JB, Gleeson FV. Lobar Ventilation in Patients with COPD Assessed with the Full-Scale Airway Network Flow Model and Xenon-enhanced Dual-Energy CT. Radiology 2020; 298:201-209. [PMID: 33231530 DOI: 10.1148/radiol.2020202485] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Background The full-scale airway network (FAN) flow model shows excellent agreement with limited functional imaging data but requires further validation prior to clinical use. Purpose To validate the ventilation distributions computed with the FAN flow model with xenon ventilation from xenon-enhanced dual-energy (DE) CT in participants with chronic obstructive pulmonary disease (COPD). Materials and Methods In this prospective study, the FAN model extracted structural data from xenon-enhanced DE CT images of men with COPD scanned between June 2012 and July 2013 to compute gas ventilation dynamics. The ventilation distributions on the middle cross-section plane, percentage lobar ventilation, and ventilation heterogeneity quantified by the coefficient of variation (CV) were compared between xenon-enhanced DE CT imaging and the FAN model. The relationship between the ventilation parameters with the densitometry and pulmonary function test results was demonstrated. The agreements and correlations between the parameters were measured using the concordance correlation coefficient and the Pearson correlation coefficient. Results Twenty-two men with COPD (mean age, 67 years ± 7 [standard deviation]) were evaluated. The percentage lobar ventilation computed with FAN showed a strong positive correlation with xenon-enhanced DE CT data (r = 0.7, P < .001). Ninety-five percent of lobar ventilation CV differences lay within 95% confidence intervals. Correlations of the percentage lobar ventilation were negative for percentage emphysema (xenon-enhanced DE CT: r = -0.38, P < .001; FAN: r = -0.23, P = .02) but were positive for percentage normal tissue volume (xenon-enhanced DE CT: r = 0.78, P < .001; FAN: r = 0.45, P < .001). Lung CVs of FAN revealed negative correlations with the spirometry results (CVFAN vs percentage predicted forced expiratory volume in 1 second: r = -0.75, P < .001; CVFAN vs ratio of forced expiratory volume in 1 second to forced vital capacity: r = -0.67, P < .001). Conclusion The full-scale airway network modeled lobar ventilation in patients with chronic obstructive pulmonary disease correlated with the xenon-enhanced dual-energy CT imaging data. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Parraga and Eddy in this issue.
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Affiliation(s)
- Minsuok Kim
- From the School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, England (M.K.); Healthy Science Institute, Ege University, Izmir, Turkey (O.D.); Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea (H.J.H., J.B.S.); Department of Oncology, University of Oxford, Oxford, England (F.V.G.); and Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Headington, England (F.V.G.)
| | - Ozkan Doganay
- From the School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, England (M.K.); Healthy Science Institute, Ege University, Izmir, Turkey (O.D.); Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea (H.J.H., J.B.S.); Department of Oncology, University of Oxford, Oxford, England (F.V.G.); and Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Headington, England (F.V.G.)
| | - Hye Jeon Hwang
- From the School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, England (M.K.); Healthy Science Institute, Ege University, Izmir, Turkey (O.D.); Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea (H.J.H., J.B.S.); Department of Oncology, University of Oxford, Oxford, England (F.V.G.); and Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Headington, England (F.V.G.)
| | - Joon Beom Seo
- From the School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, England (M.K.); Healthy Science Institute, Ege University, Izmir, Turkey (O.D.); Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea (H.J.H., J.B.S.); Department of Oncology, University of Oxford, Oxford, England (F.V.G.); and Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Headington, England (F.V.G.)
| | - Fergus V Gleeson
- From the School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Loughborough LE11 3TU, England (M.K.); Healthy Science Institute, Ege University, Izmir, Turkey (O.D.); Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea (H.J.H., J.B.S.); Department of Oncology, University of Oxford, Oxford, England (F.V.G.); and Department of Radiology, The Churchill Hospital, Oxford University Hospitals NHS Trust, Headington, England (F.V.G.)
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Abstract
Lung emphysema represents a major public health burden and still accounts for five percent of all deaths worldwide. Hence, it is essential to further understand this disease in order to develop effective diagnostic and therapeutic strategies. Lung emphysema is an irreversible enlargement of the airways distal to the terminal bronchi (i.e., the alveoli) due to the destruction of the alveolar walls. The two most important causes of emphysema are (I) smoking and (II) α1-antitrypsin-deficiency. In the former lung emphysema is predominant in the upper lung parts, the latter is characterized by a predominance in the basal areas of the lungs. Since quantification and evaluation of the distribution of lung emphysema is crucial in treatment planning, imaging plays a central role. Imaging modalities in lung emphysema are manifold: computed tomography (CT) imaging is nowadays the gold standard. However, emerging imaging techniques like dynamic or functional magnetic resonance imaging (MRI), scintigraphy and lately also the implementation of radiomics and artificial intelligence are more and more diffused in the evaluation, diagnosis and quantification of lung emphysema. The aim of this review is to shortly present the different subtypes of lung emphysema, to give an overview on prediction and risk assessment in emphysematous disease and to discuss not only the traditional, but also the new imaging techniques for diagnosis, quantification and evaluation of lung emphysema.
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Affiliation(s)
- Katharina Martini
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
| | - Thomas Frauenfelder
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
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Abstract
Respiratory function is fundamental in the practice of anesthesia. Knowledge of basic physiologic principles of respiration assists in the proper implementation of daily actions of induction and maintenance of general anesthesia, delivery of mechanical ventilation, discontinuation of mechanical and pharmacologic support, and return to the preoperative state. The current work provides a review of classic physiology and emphasizes features important to the anesthesiologist. The material is divided in two main sections, gas exchange and respiratory mechanics; each section presents the physiology as the basis of abnormal states. We review the path of oxygen from air to the artery and of carbon dioxide the opposite way, and we have the causes of hypoxemia and of hypercarbia based on these very footpaths. We present the actions of pressure, flow, and volume as the normal determinants of ventilation, and we review the resulting abnormalities in terms of changes of resistance and compliance.
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Utility of Iodine Density Perfusion Maps From Dual-Energy Spectral Detector CT in Evaluating Cardiothoracic Conditions: A Primer for the Radiologist. AJR Am J Roentgenol 2020; 214:775-785. [PMID: 32045305 DOI: 10.2214/ajr.19.21818] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
OBJECTIVE. The purpose of this article is to outline the utility of iodine density maps for evaluating cardiothoracic disease and abnormalities. Multiple studies have shown that the variety of images generated from dual-energy spectral detector CT (SDCT) improve identification of cardiothoracic conditions. CONCLUSION. Understanding the technique of SDCT and being familiar with the features of different cardiothoracic conditions on iodine density map images help the radiologist make a better diagnosis.
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Ohno Y, Fujisawa Y, Sugihara N, Kishida Y, Koyama H, Seki S, Yoshikawa T. Wash-in/wash-out phase xenon-enhanced area-detector CT (ADCT): utility for regional ventilation, pulmonary functional loss and clinical stage evaluations of smokers. Acta Radiol 2019; 60:1619-1628. [PMID: 30997827 DOI: 10.1177/0284185119840647] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Affiliation(s)
- Yoshiharu Ohno
- Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan
| | | | | | - Yuji Kishida
- Division of Radiology, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Hisanobu Koyama
- Department of Radiology, Osaka Police Hospital, Osaka, Japan
| | - Shinichiro Seki
- Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Takeshi Yoshikawa
- Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Japan
- Advanced Biomedical Imaging Research Center, Kobe University Graduate School of Medicine, Kobe, Japan
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12
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Young HM, Eddy RL, Parraga G. MRI and CT lung biomarkers: Towards an in vivo understanding of lung biomechanics. Clin Biomech (Bristol, Avon) 2019; 66:107-122. [PMID: 29037603 DOI: 10.1016/j.clinbiomech.2017.09.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2017] [Revised: 09/22/2017] [Accepted: 09/27/2017] [Indexed: 02/07/2023]
Abstract
BACKGROUND The biomechanical properties of the lung are necessarily dependent on its structure and function, both of which are complex and change over time and space. This makes in vivo evaluation of lung biomechanics and a deep understanding of lung biomarkers, very challenging. In patients and animal models of lung disease, in vivo evaluations of lung structure and function are typically made at the mouth and include spirometry, multiple-breath gas washout tests and the forced oscillation technique. These techniques, and the biomarkers they provide, incorporate the properties of the whole organ system including the parenchyma, large and small airways, mouth, diaphragm and intercostal muscles. Unfortunately, these well-established measurements mask regional differences, limiting their ability to probe the lung's gross and micro-biomechanical properties which vary widely throughout the organ and its subcompartments. Pulmonary imaging has the advantage in providing regional, non-invasive measurements of healthy and diseased lung, in vivo. Here we summarize well-established and emerging lung imaging tools and biomarkers and how they may be used to generate lung biomechanical measurements. METHODS We review well-established and emerging lung anatomical, microstructural and functional imaging biomarkers generated using synchrotron x-ray tomographic-microscopy (SRXTM), micro-x-ray computed-tomography (micro-CT), clinical CT as well as magnetic resonance imaging (MRI). FINDINGS Pulmonary imaging provides measurements of lung structure, function and biomechanics with high spatial and temporal resolution. Imaging biomarkers that reflect the biomechanical properties of the lung are now being validated to provide a deeper understanding of the lung that cannot be achieved using measurements made at the mouth.
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Affiliation(s)
- Heather M Young
- Robarts Research Institute, Western University, London, Canada; Department of Medical Biophysics, Western University, London, Canada
| | - Rachel L Eddy
- Robarts Research Institute, Western University, London, Canada; Department of Medical Biophysics, Western University, London, Canada
| | - Grace Parraga
- Robarts Research Institute, Western University, London, Canada; Department of Medical Biophysics, Western University, London, Canada; Graduate Program in Biomedical Engineering, Western University, London, Canada.
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Comparison of Radiation Dose and Image Quality of Contrast-Enhanced Dual-Source CT of the Chest: Single-Versus Dual-Energy and Second-Versus Third-Generation Technology. AJR Am J Roentgenol 2019; 212:741-747. [PMID: 30699006 DOI: 10.2214/ajr.18.20065] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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14
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Quantitative assessment of pulmonary vascular alterations in chronic obstructive lung disease: Associations with pulmonary function test and survival in the KOLD cohort. Eur J Radiol 2018; 108:276-282. [PMID: 30396668 DOI: 10.1016/j.ejrad.2018.09.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 09/04/2018] [Accepted: 09/11/2018] [Indexed: 11/23/2022]
Abstract
PURPOSE Despite the high prevalence of pulmonary vascular alterations and their substantial impact on chronic obstructive pulmonary disease (COPD), tools for the direct in vivo assessment of pulmonary vascular alterations remain limited. Thus, the purpose of this study was to automatically extract pulmonary vessels from volumetric chest CT and evaluate the associations between the derived quantitative pulmonary vessel features and clinical parameters, including survival, in COPD patients. METHODS This study included 344 adult COPD patients. Pulmonary vessels were automatically extracted from volumetric chest CT data. Quantitative pulmonary vessel features were obtained from various lung surface areas (LSAs), which are theoretical surface areas drawn at different depths from the pleural borders. The total number of vessels (Ntotal) and number of vessels with vessel area (VA) less than 5 mm2 (N<5mm) were counted as both robust values and as values per 10 cm2 of LSA (Ntotal/LSA; N<5mm/LSA). The average VA (VAmean) and percentage of measured VA in the corresponding LSA (%VA) were measured. Associations between quantitative pulmonary vessel features and clinical parameters, including survival and the pulmonary function test (PFT), were evaluated. RESULTS The pulmonary vessels were automatically extracted with 100% technical success. Cox regression analysis showed Ntotal/LSA, N<5mm/LSA, VAmean, and %VA to be significant predictors of survival (hazard ratio (HR), 0.80, 0.75, 0.70, 0.49, respectively). Patients classified into high-risk groups by %VA18mm (cut-off = 3.258), chosen because it demonstrated the strongest statistical influence on survival in a univariate Cox analysis, were associated with worse overall survival before (HR, 4.83; p < 0.001) and after adjustment for patient age and BMI (HR, 2.18; p = 0.014). Of the quantitative pulmonary vessel features, Ntotal/LSA, N<5mm/LSA, and %VA were correlated with FEV1, FEV1/FVC, and DLCO in all LSAs. The strongest correlation with PFTs was noted at LSA9mm for both Ntotal (FEV1, r = 0.33; FEV1/FVC, r = 0.51) and N<5mm (FEV1, r = 0.35; FEV1/FVC, r = 0.52). For %VA, the association was most evident at LSA18mm (FEV1, r = 0.27; FEV1/FVC, r = 0.47). Significant moderate to strong correlations were consistently observed between the extent of emphysema and quantitative pulmonary vessel features (r = 0.44-0.66; all p < 0.001). CONCLUSIONS The automated extraction of pulmonary vessels and their quantitative assessment are technically feasible. Various quantitative pulmonary vessel features demonstrated significant relationships with survival and PFT in COPD patients. Of the various quantitative features, the percentage of total VA measured at 18 mm depth from the pleural surface (%VA18mm) and the number of small vessels counted per 10 cm2 of LSA at 9 mm depth from the pleural surface (N<5mm/LSA9mm) had the strongest predictability for the clinical parameters.
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Abstract
Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death worldwide. One of the main findings is pulmonary emphysema in association with chronic bronchitis. Clinical signs, pulmonary function tests and imaging are the current used methods to diagnose and stage emphysema. Lung volume reduction (LVR) and endoscopic lung volume reduction (ELVR) are the current therapeutic options beside lung transplantation in cases of severe emphysema. Nowadays imaging is one of the key factors for the success of these therapies. Especially quantitative computed tomography (CT) with its increasing possibilities has become a viable tool, providing detailed information about distribution and heterogeneity of emphysema. Other imaging techniques like dual-energy CT (DECT) and functional magnetic resonance (MR) have shown to add functional information. These structural and functional information support thoracic surgeons and interventional pulmonologists in selecting patients and optimizing LVR procedures but also enables the development of new endobronchial therapies. Imaging will further improve the individual outcome by supporting the choice of optimal therapy.
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Affiliation(s)
- Katharina Martini
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
| | - Thomas Frauenfelder
- Institute of Diagnostic and Interventional Radiology, University Hospital Zurich, Zurich, Switzerland
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Comparison of Xenon-Enhanced Area-Detector CT and Krypton Ventilation SPECT/CT for Assessment of Pulmonary Functional Loss and Disease Severity in Smokers. AJR Am J Roentgenol 2017; 210:W45-W53. [PMID: 29220212 DOI: 10.2214/ajr.17.18709] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVE The objective of this study was to compare the capability of xenon-enhanced area-detector CT (ADCT) performed with a subtraction technique and coregistered 81mKr-ventilation SPECT/CT for the assessment of pulmonary functional loss and disease severity in smokers. SUBJECTS AND METHODS Forty-six consecutive smokers (32 men and 14 women; mean age, 67.0 years) underwent prospective unenhanced and xenon-enhanced ADCT, 81mKr-ventilation SPECT/CT, and pulmonary function tests. Disease severity was evaluated according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) classification. CT-based functional lung volume (FLV), the percentage of wall area to total airway area (WA%), and ventilated FLV on xenon-enhanced ADCT and SPECT/CT were calculated for each smoker. All indexes were correlated with percentage of forced expiratory volume in 1 second (%FEV1) using step-wise regression analyses, and univariate and multivariate logistic regression analyses were performed. In addition, the diagnostic accuracy of the proposed model was compared with that of each radiologic index by means of McNemar analysis. RESULTS Multivariate logistic regression showed that %FEV1 was significantly affected (r = 0.77, r2 = 0.59) by two factors: the first factor, ventilated FLV on xenon-enhanced ADCT (p < 0.0001); and the second factor, WA% (p = 0.004). Univariate logistic regression analyses indicated that all indexes significantly affected GOLD classification (p < 0.05). Multivariate logistic regression analyses revealed that ventilated FLV on xenon-enhanced ADCT and CT-based FLV significantly influenced GOLD classification (p < 0.0001). The diagnostic accuracy of the proposed model was significantly higher than that of ventilated FLV on SPECT/CT (p = 0.03) and WA% (p = 0.008). CONCLUSION Xenon-enhanced ADCT is more effective than 81mKr-ventilation SPECT/CT for the assessment of pulmonary functional loss and disease severity.
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Yamashiro T, Moriya H, Matsuoka S, Nagatani Y, Tsubakimoto M, Tsuchiya N, Murayama S. Asynchrony in respiratory movements between the pulmonary lobes in patients with COPD: continuous measurement of lung density by 4-dimensional dynamic-ventilation CT. Int J Chron Obstruct Pulmon Dis 2017; 12:2101-2109. [PMID: 28790813 PMCID: PMC5530056 DOI: 10.2147/copd.s140247] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose Four-dimensional dynamic-ventilation CT imaging demonstrates continuous movement of the lung. The aim of this study was to assess the correlation between interlobar synchrony in lung density and spirometric values in COPD patients and smokers, by measuring the continuous changes in lung density during respiration on the dynamic-ventilation CT. Materials and methods Thirty-two smokers, including ten with COPD, underwent dynamic-ventilation CT during free breathing. CT data were continuously reconstructed every 0.5 sec. Mean lung density (MLD) of the five lobes (right upper [RU], right middle [RM], right lower [RL], left upper [LU], and left lower [LL]) was continuously measured by commercially available software using a fixed volume of volume of interest which was placed and tracked on a single designated point in each lobe. Concordance between the MLD time curves of six pairs of lung lobes (RU-RL, RU-RM, RM-RL, LU-LL, RU-LU, and RL-LL lobes) was expressed by cross-correlation coefficients. The relationship between these cross-correlation coefficients and the forced expiratory volume in one second/forced vital capacity (FEV1.0/FVC) values was assessed by Spearman rank correlation analysis. Results In all six pairs of the pulmonary lobes, the cross-correlation coefficients of the two MLD curves were significantly positively correlated with FEV1.0/FVC (ρ =0.60–0.73, P<0.001). The mean value of the six coefficients strongly correlated with FEV1.0/FVC (ρ =0.80, P<0.0001). Conclusion The synchrony of respiratory movements between the pulmonary lobes is limited or lost in patients with more severe airflow limitation.
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Affiliation(s)
- Tsuneo Yamashiro
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Hiroshi Moriya
- Department of Radiology, Ohara General Hospital, Fukushima-City, Fukushima, Japan
| | - Shin Matsuoka
- Department of Radiology, St Marianna University School of Medicine, Kawasaki, Kanagawa, Japan
| | - Yukihiro Nagatani
- Department of Radiology, Shiga University of Medical Science, Otsu, Shiga, Japan
| | - Maho Tsubakimoto
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Nanae Tsuchiya
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan
| | - Sadayuki Murayama
- Department of Radiology, Graduate School of Medical Science, University of the Ryukyus, Nishihara, Okinawa, Japan
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