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Moore J, Remy J, Altschul E, Chusid J, Flohr T, Raoof S, Remy-Jardin M. Thoracic Applications of Spectral CT Scan. Chest 2024; 165:417-430. [PMID: 37619663 DOI: 10.1016/j.chest.2023.07.4225] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 07/29/2023] [Accepted: 07/31/2023] [Indexed: 08/26/2023] Open
Abstract
TOPIC IMPORTANCE Thoracic imaging with CT scan has become an essential component in the evaluation of respiratory and thoracic diseases. Providers have historically used conventional single-energy CT; however, prevalence of dual-energy CT (DECT) is increasing, and as such, it is important for thoracic physicians to recognize the utility and limitations of this technology. REVIEW FINDINGS The technical aspects of DECT are presented, and practical approaches to using DECT are provided. Imaging at multiple energy spectra allows for postprocessing of the data and the possibility of creating multiple distinct image reconstructions based on the clinical question being asked. The data regarding utility of DECT in pulmonary vascular disorders, ventilatory defects, and thoracic oncology are presented. A pictorial essay is provided to give examples of the strengths associated with DECT. SUMMARY DECT has been most heavily studied in chronic thromboembolic pulmonary hypertension; however, it is increasingly being used across a wide spectrum of thoracic diseases. DECT combines morphologic and functional assessments in a single imaging acquisition, providing clinicians with a powerful diagnostic tool. Its role in the evaluation and treatment of thoracic diseases will likely continue to expand in the coming years as clinicians become more experienced with the technology.
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Affiliation(s)
- Jonathan Moore
- Department of Pulmonary and Critical Care Medicine, Lenox Hill Hospital, Northwell Health Physician Partners, New York, NY
| | - Jacques Remy
- Univ Lille, Department of Thoracic Imaging, Lille, France
| | - Erica Altschul
- Department of Pulmonary and Critical Care Medicine, Lenox Hill Hospital, Northwell Health Physician Partners, New York, NY
| | - Jesse Chusid
- Feinstein Institutes for Medical Research, and Imaging Services, Department of Radiology, Northwell Health, Manhasset, NY
| | - Thomas Flohr
- Department of Computed Tomography Research & Development, Siemens Healthineers, Forchheim, Germany
| | - Suhail Raoof
- Department of Pulmonary and Critical Care Medicine, Lenox Hill Hospital, Northwell Health Physician Partners, New York, NY.
| | - Martine Remy-Jardin
- Univ Lille, Department of Thoracic Imaging, Lille, France; Univ Lille, CHU Lille, Evaluation des technologies de santé et des pratiques médicales, Lille, France
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Hoffman EA. Origins of and lessons from quantitative functional X-ray computed tomography of the lung. Br J Radiol 2022; 95:20211364. [PMID: 35193364 PMCID: PMC9153696 DOI: 10.1259/bjr.20211364] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/20/2022] [Accepted: 01/27/2022] [Indexed: 12/16/2022] Open
Abstract
Functional CT of the lung has emerged from quantitative CT (qCT). Structural details extracted at multiple lung volumes offer indices of function. Additionally, single volumetric images, if acquired at standardized lung volumes and body posture, can be used to model function by employing such engineering techniques as computational fluid dynamics. With the emergence of multispectral CT imaging including dual energy from energy integrating CT scanners and multienergy binning using the newly released photon counting CT technology, function is tagged via use of contrast agents. Lung disease phenotypes have previously been lumped together by the limitations of spirometry and plethysmography. QCT and its functional embodiment have been imbedded into studies seeking to characterize chronic obstructive pulmonary disease, severe asthma, interstitial lung disease and more. Reductions in radiation dose by an order of magnitude or more have been achieved. At the same time, we have seen significant increases in spatial and density resolution along with methodologic validations of extracted metrics. Together, these have allowed attention to turn towards more mild forms of disease and younger populations. In early applications, clinical CT offered anatomic details of the lung. Functional CT offers regional measures of lung mechanics, the assessment of functional small airways disease, as well as regional ventilation-perfusion matching (V/Q) and more. This paper will focus on the use of quantitative/functional CT for the non-invasive exploration of dynamic three-dimensional functioning of the breathing lung and beating heart within the unique negative pressure intrathoracic environment of the closed chest.
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Affiliation(s)
- Eric A Hoffman
- Departments of Radiology, Internal Medicine and Biomedical Engineering University of Iowa, Iowa, United States
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Miller J, DiMaso L, Huang‐Vredevoogd J, Shah J, Lawless M. Characterization of size-specific effects during dual-energy CT material decomposition of non-iodine materials. J Appl Clin Med Phys 2021; 22:168-176. [PMID: 34783427 PMCID: PMC8664138 DOI: 10.1002/acm2.13471] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 10/05/2021] [Accepted: 10/20/2021] [Indexed: 12/11/2022] Open
Abstract
PURPOSE The dual-energy CT (DECT) LiverVNC application class in the Siemens Syngo.via software has been used to perform non-iodine material decompositions. However, the LiverVNC application is designed with an optional size-specific calibration based on iodine measurements. This work investigates the effects of this iodine-based size-specific calibration on non-iodine material decomposition and benchmarks alternative methods for size-specific calibrations. METHODS Calcium quantification was performed with split-filter and sequential-scanning DECT techniques on the Siemens SOMATOM Definition Edge CT scanner. Images were acquired of the Gammex MECT abdomen and head phantom containing calcium inserts with concentrations ranging from 50-300 mgCa/ml. Several workflows were explored investigating the effects of size-specific dual-energy ratios (DERs) and the beam hardening correction (BHC) function in the LiverVNC application. Effects of image noise were also investigated by varying CTDIvol and using iterative reconstruction (ADMIRE). RESULTS With the default BHC activated, Syngo.via underestimated the calcium concentrations in the abdomen for sequential-scanning acquisitions, leaving residual calcium in the virtual non-contrast images and underestimating calcium in the enhancement images for all DERs. Activation of the BHC with split-filter images resulted in a calcium over- or underestimation depending on the DER. With the BHC inactivated, the use of a single DER led to an under- or overestimate of calcium concentration depending on phantom size and DECT modality. Optimal results were found with BHC inactivated using size-specific DERs. CTDIvol levels and ADMIRE had no significant effect on results. CONCLUSION When performing non-iodine material decomposition in the LiverVNC application class, it is important to understand the implications of the BHC function and to account for patient size appropriately. The BHC in the LiverVNC application is specific to iodine and leads to inaccurate quantification of other materials. The inaccuracies can be overcome by deactivating the BHC function and using size-specific DERs, which provided the most accurate calcium quantification.
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Affiliation(s)
- Jessica Miller
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
- Department of Medical PhysicsUniversity of WisconsinMadisonWisconsinUSA
| | - Lianna DiMaso
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
| | - Jessie Huang‐Vredevoogd
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
- Department of Medical PhysicsUniversity of WisconsinMadisonWisconsinUSA
| | - Jainil Shah
- Siemens Medical Solutions USA, Inc.MalvernPennsylvaniaUSA
| | - Michael Lawless
- Department of Human OncologyUniversity of WisconsinMadisonWisconsinUSA
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4
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Ohno Y, Seo JB, Parraga G, Lee KS, Gefter WB, Fain SB, Schiebler ML, Hatabu H. Pulmonary Functional Imaging: Part 1-State-of-the-Art Technical and Physiologic Underpinnings. Radiology 2021; 299:508-523. [PMID: 33825513 DOI: 10.1148/radiol.2021203711] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Over the past few decades, pulmonary imaging technologies have advanced from chest radiography and nuclear medicine methods to high-spatial-resolution or low-dose chest CT and MRI. It is currently possible to identify and measure pulmonary pathologic changes before these are obvious even to patients or depicted on conventional morphologic images. Here, key technological advances are described, including multiparametric CT image processing methods, inhaled hyperpolarized and fluorinated gas MRI, and four-dimensional free-breathing CT and MRI methods to measure regional ventilation, perfusion, gas exchange, and biomechanics. The basic anatomic and physiologic underpinnings of these pulmonary functional imaging techniques are explained. In addition, advances in image analysis and computational and artificial intelligence (machine learning) methods pertinent to functional lung imaging are discussed. The clinical applications of pulmonary functional imaging, including both the opportunities and challenges for clinical translation and deployment, will be discussed in part 2 of this review. Given the technical advances in these sophisticated imaging methods and the wealth of information they can provide, it is anticipated that pulmonary functional imaging will be increasingly used in the care of patients with lung disease. © RSNA, 2021 Online supplemental material is available for this article.
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Affiliation(s)
- Yoshiharu Ohno
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Joon Beom Seo
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Grace Parraga
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Kyung Soo Lee
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Warren B Gefter
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Sean B Fain
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Mark L Schiebler
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
| | - Hiroto Hatabu
- From the Department of Radiology, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Joint Research Laboratory of Advanced Medical Imaging, Fujita Health University School of Medicine, Toyoake, Aichi, Japan (Y.O.); Division of Functional and Diagnostic Imaging Research, Department of Radiology, Kobe University Graduate School of Medicine, Kobe, Hyogo, Japan (Y.O.); Department of Radiology, Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea (J.B.S.); Department of Medicine, Robarts Research Institute, and Department of Medical Biophysics, Western University, London, Canada (G.P.); Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine (SKKU-SOM), Seoul, Korea (K.S.L.); Department of Radiology, Penn Medicine, University of Pennsylvania, Philadelphia, Pa (W.B.G.); Departments of Medical Physics and Radiology (S.B.F., M.L.S.), UW-Madison School of Medicine and Public Health, Madison, Wis; and Center for Pulmonary Functional Imaging, Brigham and Women's Hospital and Harvard Medical School, 75 Francis St, Boston, MA 02215 (H.H.)
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Debray MP, Ghanem M, Khalil A, Taillé C. [Lung imaging in severe asthma]. Rev Mal Respir 2021; 38:41-57. [PMID: 33423858 DOI: 10.1016/j.rmr.2020.09.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/02/2020] [Indexed: 01/15/2023]
Abstract
INTRODUCTION Asthma is a common disease whose diagnosis does not typically rely on the results of imaging. However, chest CT has gained a key place over the last decade to support the management of patients with difficult to treat and severe asthma. STATE OF THE ART Bronchial wall thickening and mild dilatation or narrowing of bronchial lumen are frequently observed on chest CT in people with asthma. Bronchial wall thickening is correlated to the degree of obstruction and to bronchial wall remodeling and inflammation. Diverse conditions which can mimic asthma should be recognized on CT, including endobronchial tumours, interstitial pneumonias, bronchiectasis and bronchiolitis. Ground-glass opacities and consolidation may be related to transient eosinophilic infiltrates, infection or an associated disease (vasculitis, chronic eosinophilic pneumonia). Hyperdense mucous plugging is highly specific for allergic bronchopulmonary aspergillosis. PERSPECTIVES Airway morphometry, air trapping and quantitative analysis of ventilatory defects, with CT or MRI, can help to identify different morphological subgroups of patients with different functional or inflammatory characteristics. These imaging tools could emerge as new biomarkers for the evaluation of treatment response. CONCLUSION Chest CT is indicated in people with severe asthma to search for additional or alternative diagnoses. Quantitative imaging may contribute to phenotyping this patient group.
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Affiliation(s)
- M-P Debray
- Service de Radiologie, Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, 46, rue Henri Huchard, 75018 Paris; Inserm UMR1152, France.
| | - M Ghanem
- Service de Pneumologie et Centre de Référence constitutif des Maladies Pulmonaires Rares, Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, France
| | - A Khalil
- Service de Radiologie, Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, 46, rue Henri Huchard, 75018 Paris; Université de Paris, Inserm UMR1152, France
| | - C Taillé
- Service de Pneumologie et Centre de Référence constitutif des Maladies Pulmonaires Rares, Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, France; Département Hospitalo-Universitaire FIRE ; Université de Paris ; Inserm UMR 1152 ; LabEx Inflamex, 75018 Paris, France
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Hopkins SR. Ventilation/Perfusion Relationships and Gas Exchange: Measurement Approaches. Compr Physiol 2020; 10:1155-1205. [PMID: 32941684 DOI: 10.1002/cphy.c180042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Ventilation-perfusion ( V ˙ A / Q ˙ ) matching, the regional matching of the flow of fresh gas to flow of deoxygenated capillary blood, is the most important mechanism affecting the efficiency of pulmonary gas exchange. This article discusses the measurement of V ˙ A / Q ˙ matching with three broad classes of techniques: (i) those based in gas exchange, such as the multiple inert gas elimination technique (MIGET); (ii) those derived from imaging techniques such as single-photon emission computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI), computed tomography (CT), and electrical impedance tomography (EIT); and (iii) fluorescent and radiolabeled microspheres. The focus is on the physiological basis of these techniques that provide quantitative information for research purposes rather than qualitative measurements that are used clinically. The fundamental equations of pulmonary gas exchange are first reviewed to lay the foundation for the gas exchange techniques and some of the imaging applications. The physiological considerations for each of the techniques along with advantages and disadvantages are briefly discussed. © 2020 American Physiological Society. Compr Physiol 10:1155-1205, 2020.
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Affiliation(s)
- Susan R Hopkins
- Departments of Medicine and Radiology, University of California, San Diego, California, USA
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Agostini A, Borgheresi A, Mari A, Floridi C, Bruno F, Carotti M, Schicchi N, Barile A, Maggi S, Giovagnoni A. Dual-energy CT: theoretical principles and clinical applications. Radiol Med 2019; 124:1281-1295. [PMID: 31792703 DOI: 10.1007/s11547-019-01107-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/13/2019] [Indexed: 01/01/2023]
Abstract
The physical principles of dual-energy computed tomography (DECT) are as old as computed tomography (CT) itself. To understand the strengths and the limits of this technology, a brief overview of theoretical basis of DECT will be provided. Specific attention will be focused on the interaction of X-rays with matter, on the principles of attenuation of X-rays in CT toward the intrinsic limits of conventional CT, on the material decomposition algorithms (two- and three-basis-material decomposition algorithms) and on effective Rho-Z methods. The progresses in material decomposition algorithms, in computational power of computers and in CT hardware, lead to the development of different technological solutions for DECT in clinical practice. The clinical applications of DECT are briefly reviewed in relation to the specific algorithms.
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Affiliation(s)
- Andrea Agostini
- Department of Clinical, Special and Dental Sciences, University Politecnica delle Marche, Ancona, Italy.
- Department of Radiology - Division of Special and Pediatric Radiology, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy.
| | - Alessandra Borgheresi
- Department of Radiology - Division of Special and Pediatric Radiology, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy
| | - Alberto Mari
- Department of Radiology - Division of Medical Physics, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy
| | - Chiara Floridi
- Department of Health Sciences, Diagnostic and Interventional Radiology, Hospital "San Paolo", University of Milan, Milan, Italy
| | - Federico Bruno
- Department of Biotechnological and Applied Sciences, University of L'Aquila, Via Vetoio 1, 67100, L'Aquila, Italy
| | - Marina Carotti
- Department of Radiology - Division of Special and Pediatric Radiology, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy
| | - Nicolò Schicchi
- Department of Radiology - Division of Special and Pediatric Radiology, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy
| | - Antonio Barile
- Department of Biotechnological and Applied Sciences, University of L'Aquila, Via Vetoio 1, 67100, L'Aquila, Italy
| | - Stefania Maggi
- Department of Radiology - Division of Medical Physics, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy
| | - Andrea Giovagnoni
- Department of Clinical, Special and Dental Sciences, University Politecnica delle Marche, Ancona, Italy
- Department of Radiology - Division of Special and Pediatric Radiology, University Hospital "Umberto I - Lancisi - Salesi", Via Conca 71, 60126, Ancona, AN, Italy
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Pinkham DW, Negahdar M, Yamamoto T, Mittra E, Diehn M, Nair VS, Keall PJ, Maxim PG, Loo BW. A Feasibility Study of Single-inhalation, Single-energy Xenon-enhanced CT for High-resolution Imaging of Regional Lung Ventilation in Humans. Acad Radiol 2019; 26:38-49. [PMID: 29606339 DOI: 10.1016/j.acra.2018.03.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/01/2018] [Accepted: 03/07/2018] [Indexed: 11/30/2022]
Abstract
RATIONALE AND OBJECTIVES The objective of this study was to assess the feasibility of single-inhalation xenon-enhanced computed tomography (XeCT) to provide clinically practical, high-resolution pulmonary ventilation imaging to clinics with access to only a single-energy computed tomography scanner, and to reduce the subject's overall exposure to xenon by utilizing a higher (70%) concentration for a much shorter time than has been employed in prior studies. MATERIALS AND METHODS We conducted an institutional review board-approved prospective feasibility study of XeCT for 15 patients undergoing thoracic radiotherapy. For XeCT, we acquired two breath-hold single-energy computed tomography images of the entire lung with a single inhalation each of 100% oxygen and a mixture of 70% xenon and 30% oxygen, respectively. A video biofeedback system for coached patient breathing was used to achieve reproducible breath holds. We assessed the technical success of XeCT acquisition and side effects. We then used deformable image registration to align the breath-hold images with each other to accurately subtract them, producing a map of lung xenon distribution. Additionally, we acquired ventilation single-photon emission computed tomography-computed tomography (V-SPECT-CT) images for 11 of the 15 patients. For a comparative analysis, we partitioned each lung into 12 sectors, calculated the xenon concentration from the Hounsfield unit enhancement in each sector, and then correlated this with the corresponding V-SPECT-CT counts. RESULTS XeCT scans were tolerated well overall, with a mild (grade 1) dizziness as the only side effect in 5 of the 15 patients. Technical failures in five patients occurred because of inaccurate breathing synchronization with xenon gas delivery, leaving seven patients analyzable for XeCT and single-photon emission computed tomography correlation. Sector-wise correlations were strong (Spearman coefficient >0.75, Pearson coefficient >0.65, P value <.002) for two patients for whom ventilation deficits were visibly pronounced in both scans. Correlations were nonsignificant for the remaining five who had more homogeneous XeCT ventilation maps, as well as strong V-SPECT-CT imaging artifacts attributable to airway deposition of the aerosolized imaging agent. Qualitatively, XeCT demonstrated higher resolution and no central airway deposition artifacts compared to V-SPECT-CT. CONCLUSIONS In this pilot study, single-breath XeCT ventilation imaging was generally feasible for patients undergoing thoracic radiotherapy, using an imaging protocol that is clinically practical and potentially widely available. In the future, the xenon delivery failures can be addressed by straightforward technical improvements to the patient biofeedback coaching system.
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Affiliation(s)
- Daniel W Pinkham
- Department of Radiation Oncology, Stanford University, 875 Blake Wilbur Dr., Stanford, CA 94305
| | - Mohammadreza Negahdar
- Department of Radiation Oncology, Stanford University, 875 Blake Wilbur Dr., Stanford, CA 94305; Almaden Research Center, IBM Research, San Jose, California
| | - Tokihiro Yamamoto
- Department of Radiation Oncology, University of California, Davis, Sacramento, California
| | - Erik Mittra
- Department of Radiology, Stanford University, Stanford, California
| | - Maximilian Diehn
- Department of Radiation Oncology, Stanford University, 875 Blake Wilbur Dr., Stanford, CA 94305
| | - Viswam S Nair
- Division of Pulmonary & Critical Care Medicine, Stanford University, Stanford, California
| | - Paul J Keall
- Radiation Physics Laboratory, The University of Sydney, NSW, Australia
| | - Peter G Maxim
- Department of Radiation Oncology, Stanford University, 875 Blake Wilbur Dr., Stanford, CA 94305.
| | - Billy W Loo
- Department of Radiation Oncology, Stanford University, 875 Blake Wilbur Dr., Stanford, CA 94305.
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Goo HW, Goo JM. Dual-Energy CT: New Horizon in Medical Imaging. Korean J Radiol 2017; 18:555-569. [PMID: 28670151 PMCID: PMC5447632 DOI: 10.3348/kjr.2017.18.4.555] [Citation(s) in RCA: 245] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2017] [Accepted: 02/23/2017] [Indexed: 12/18/2022] Open
Abstract
Dual-energy CT has remained underutilized over the past decade probably due to a cumbersome workflow issue and current technical limitations. Clinical radiologists should be made aware of the potential clinical benefits of dual-energy CT over single-energy CT. To accomplish this aim, the basic principle, current acquisition methods with advantages and disadvantages, and various material-specific imaging methods as clinical applications of dual-energy CT should be addressed in detail. Current dual-energy CT acquisition methods include dual tubes with or without beam filtration, rapid voltage switching, dual-layer detector, split filter technique, and sequential scanning. Dual-energy material-specific imaging methods include virtual monoenergetic or monochromatic imaging, effective atomic number map, virtual non-contrast or unenhanced imaging, virtual non-calcium imaging, iodine map, inhaled xenon map, uric acid imaging, automatic bone removal, and lung vessels analysis. In this review, we focus on dual-energy CT imaging including related issues of radiation exposure to patients, scanning and post-processing options, and potential clinical benefits mainly to improve the understanding of clinical radiologists and thus, expand the clinical use of dual-energy CT; in addition, we briefly describe the current technical limitations of dual-energy CT and the current developments of photon-counting detector.
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Affiliation(s)
- Hyun Woo Goo
- Department of Radiology and Research Institute of Radiology, Asan Medical Center, University of Ulsan College of Medicine, Seoul 05505, Korea
| | - Jin Mo Goo
- Department of Radiology, Seoul National University College of Medicine, Seoul 03080, Korea
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White Paper of the Society of Computed Body Tomography and Magnetic Resonance on Dual-Energy CT, Part 3. J Comput Assist Tomogr 2017; 41:1-7. [DOI: 10.1097/rct.0000000000000538] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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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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Hong SR, Chang S, Im DJ, Suh YJ, Hong YJ, Hur J, Kim YJ, Choi BW, Lee HJ. Feasibility of Single Scan for Simultaneous Evaluation of Regional Krypton and Iodine Concentrations with Dual-Energy CT: An Experimental Study. Radiology 2016; 281:597-605. [PMID: 27203543 DOI: 10.1148/radiol.16152429] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Purpose To evaluate the feasibility of a simultaneous single scan of regional krypton and iodine concentrations by using dual-energy computed tomography (CT). Materials and Methods The study was approved by the institutional animal experimental committee. An airway obstruction model was first made in 10 beagle dogs, and a pulmonary arterial occlusion was induced in each animal after 1 week. For each model, three sessions of dual-energy CT (80% krypton ventilation [krypton CT], 80% krypton ventilation with iodine enhancement [mixed-contrast agent CT], and iodine enhancement [iodine CT]) were performed. Krypton maps were made from krypton and mixed-contrast agent CT, and iodine maps were made from iodine and mixed-contrast agent CT. Observers measured overlay Hounsfield units of the diseased and contralateral segments on each map. Values were compared by using the Wilcoxon signed-rank test. Results In krypton maps of airway obstruction, overlay Hounsfield units of diseased segments were significantly decreased compared with those of contralateral segments in both krypton and mixed-contrast agent CT (P = .005 for both). However, the values of mixed-contrast agent CT were significantly higher than those of krypton CT for both segments (P = .005 and .007, respectively). In iodine maps of pulmonary arterial occlusion, values were significantly lower in diseased segments than in contralateral segments for both iodine and mixed-contrast agent CT (P = .005 for both), without significant difference between iodine and mixed-contrast agent CT for both segments (P = .126 and .307, respectively). Conclusion Although some limitations may exist, it might be feasible to analyze regional krypton and iodine concentrations simultaneously by using dual-energy CT. © RSNA, 2016.
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Affiliation(s)
- Sae Rom Hong
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Suyon Chang
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Dong Jin Im
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Young Joo Suh
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Yoo Jin Hong
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Jin Hur
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Young Jin Kim
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Byoung Wook Choi
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
| | - Hye-Jeong Lee
- From the Department of Radiology, Research Institute of Radiological Science, Severance Hospital, Yonsei University College of Medicine, 50-1 Yonsei-ro, Seodaemun-gu, Seoul 120-752, Korea
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van Elmpt W, Landry G, Das M, Verhaegen F. Dual energy CT in radiotherapy: Current applications and future outlook. Radiother Oncol 2016; 119:137-44. [DOI: 10.1016/j.radonc.2016.02.026] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 01/13/2016] [Accepted: 02/28/2016] [Indexed: 11/17/2022]
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Lilburn DML, Lesbats C, Six JS, Dubuis E, Yew-Booth L, Shaw DE, Belvisi MG, Birrell MA, Pavlovskaya GE, Meersmann T. Hyperpolarized 83Kr magnetic resonance imaging of alveolar degradation in a rat model of emphysema. J R Soc Interface 2016; 12:rsif.2015.0192. [PMID: 25994296 PMCID: PMC4587540 DOI: 10.1098/rsif.2015.0192] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Hyperpolarized 83Kr surface quadrupolar relaxation (SQUARE) generates MRI contrast that was previously shown to correlate with surface-to-volume ratios in porous model surface systems. The underlying physics of SQUARE contrast is conceptually different from any other current MRI methodology as the method uses the nuclear electric properties of the spin I = 9/2 isotope 83Kr. To explore the usage of this non-radioactive isotope for pulmonary pathophysiology, MRI SQUARE contrast was acquired in excised rat lungs obtained from an elastase-induced model of emphysema. A significant 83Kr T1 relaxation time increase in the SQUARE contrast was found in the elastase-treated lungs compared with the baseline data from control lungs. The SQUARE contrast suggests a reduction in pulmonary surface-to-volume ratio in the emphysema model that was validated by histology. The finding supports usage of 83Kr SQUARE as a new biomarker for surface-to-volume ratio changes in emphysema.
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Affiliation(s)
- David M L Lilburn
- Sir Peter Mansfield Imaging Centre, Division for Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham NG7 2RD, UK
| | - Clémentine Lesbats
- Sir Peter Mansfield Imaging Centre, Division for Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham NG7 2RD, UK
| | - Joseph S Six
- Sir Peter Mansfield Imaging Centre, Division for Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham NG7 2RD, UK
| | - Eric Dubuis
- Respiratory Pharmacology, Pharmacology and Toxicology, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK
| | - Liang Yew-Booth
- Respiratory Pharmacology, Pharmacology and Toxicology, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK
| | - Dominick E Shaw
- City Hospital Nottingham, Nottingham Respiratory Research Unit, Nottingham NG5 1PB, UK
| | - Maria G Belvisi
- Respiratory Pharmacology, Pharmacology and Toxicology, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK
| | - Mark A Birrell
- Respiratory Pharmacology, Pharmacology and Toxicology, Faculty of Medicine, National Heart and Lung Institute, Imperial College London, London SW7 2AZ, UK
| | - Galina E Pavlovskaya
- Sir Peter Mansfield Imaging Centre, Division for Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham NG7 2RD, UK
| | - Thomas Meersmann
- Sir Peter Mansfield Imaging Centre, Division for Respiratory Medicine, School of Medicine, University of Nottingham, Nottingham NG7 2RD, UK
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Hoffman EA, Lynch DA, Barr RG, van Beek EJR, Parraga G. Pulmonary CT and MRI phenotypes that help explain chronic pulmonary obstruction disease pathophysiology and outcomes. J Magn Reson Imaging 2016; 43:544-57. [PMID: 26199216 PMCID: PMC5207206 DOI: 10.1002/jmri.25010] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022] Open
Abstract
Pulmonary x-ray computed tomographic (CT) and magnetic resonance imaging (MRI) research and development has been motivated, in part, by the quest to subphenotype common chronic lung diseases such as chronic obstructive pulmonary disease (COPD). For thoracic CT and MRI, the main COPD research tools, disease biomarkers are being validated that go beyond anatomy and structure to include pulmonary functional measurements such as regional ventilation, perfusion, and inflammation. In addition, there has also been a drive to improve spatial and contrast resolution while at the same time reducing or eliminating radiation exposure. Therefore, this review focuses on our evolving understanding of patient-relevant and clinically important COPD endpoints and how current and emerging MRI and CT tools and measurements may be exploited for their identification, quantification, and utilization. Since reviews of the imaging physics of pulmonary CT and MRI and reviews of other COPD imaging methods were previously published and well-summarized, we focus on the current clinical challenges in COPD and the potential of newly emerging MR and CT imaging measurements to address them. Here we summarize MRI and CT imaging methods and their clinical translation for generating reproducible and sensitive measurements of COPD related to pulmonary ventilation and perfusion as well as parenchyma morphology. The key clinical problems in COPD provide an important framework in which pulmonary imaging needs to rapidly move in order to address the staggering burden, costs, as well as the mortality and morbidity associated with COPD.
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Affiliation(s)
- Eric A Hoffman
- Department of Radiology, University of Iowa, Iowa City, Iowa, USA
- Department of Internal Medicine, University of Iowa, Iowa City, Iowa, USA
- Department of Biomedical Engineering, University of Iowa, Iowa City, Iowa, USA
| | - David A Lynch
- Department of Radiology, National Jewish Health Center, Denver, Colorado, USA
| | - R Graham Barr
- Division of General Medicine, Division of Pulmonary, Allergy and Critical Care, Department of Medicine, Columbia University Medical Center, New York, New York, USA
- Department of Epidemiology, Columbia University Medical Center, New York, New York, USA
| | - Edwin J R van Beek
- Clinical Research Imaging Centre, Queen's Medical Research Institute, University of Edinburgh, Scotland, UK
| | - Grace Parraga
- Robarts Research Institute, University of Western Ontario, London, Canada
- Department of Medical Biophysics, University of Western Ontario, London, Canada
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Abstract
OBJECTIVES The objective of this study was to assess the feasibility and safety of krypton ventilation imaging with intraindividual comparison to xenon ventilation computed tomography (CT). MATERIALS AND METHODS In a first step, attenuation of different concentrations of xenon and krypton was analyzed in a phantom setting. Thereafter, 7 male New Zealand white rabbits (4.4-6.0 kg) were included in an animal study. After orotracheal intubation, an unenhanced CT scan was obtained in end-inspiratory breath-hold. Thereafter, xenon- (30%) and krypton-enhanced (70%) ventilation CT was performed in random order. After a 2-minute wash-in of gas A, CT imaging was performed. After a 45-minute wash-out period and another 2-minute wash-in of gas B, another CT scan was performed using the same scan protocol. Heart rate and oxygen saturation were measured. Unenhanced and krypton or xenon data were registered and subtracted using a nonrigid image registration tool. Enhancement was quantified and statistically analyzed. RESULTS One animal had to be excluded from data analysis owing to problems during intubation. The CT scans in the remaining 6 animals were completed without complications. There were no relevant differences in oxygen saturation or heart rate between the scans. Xenon resulted in a mean increase of enhancement of 35.3 ± 5.5 HU, whereas krypton achieved a mean increase of 21.9 ± 1.8 HU in enhancement (P = 0.0055). CONCLUSIONS The use of krypton for lung ventilation imaging appears to be feasible and safe. Despite the use of a markedly higher concentration of krypton, enhancement is significantly worse when compared with xenon CT ventilation imaging, but sufficiently high for CT ventilation imaging studies.
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Chung YE, Hong SR, Lee MJ, Lee M, Lee HJ. Krypton-enhanced ventilation CT with dual energy technique: Experimental study for optimal krypton concentration. Exp Lung Res 2014; 40:439-46. [DOI: 10.3109/01902148.2014.946630] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Ohana M, Jeung MY, Labani A, El Ghannudi S, Roy C. Thoracic dual energy CT: acquisition protocols, current applications and future developments. Diagn Interv Imaging 2014; 95:1017-26. [PMID: 24780370 DOI: 10.1016/j.diii.2014.01.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Thanks to a simultaneous acquisition at high and low kilovoltage, dual energy computed tomography (DECT) can achieve material-based decomposition (iodine, water, calcium, etc.) and reconstruct images at different energy levels (40 to 140keV). Post-processing uses this potential to maximise iodine detection, which elicits demonstrated added value for chest imaging in acute and chronic embolic diseases (increases the quality of the examination and identifies perfusion defects), follow-up of aortic endografts and detection of contrast uptake in oncology. In CT angiography, these unique features are taken advantage of to reduce the iodine load by more than half. This review article aims to set out the physical basis for the technology, the acquisition and post-processing protocols used, its proven advantages in chest pathologies, and to present future developments.
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Affiliation(s)
- M Ohana
- Department of Radiology, Nouvel Hôpital Civil, University Hospitals of Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France.
| | - M Y Jeung
- Department of Radiology, Nouvel Hôpital Civil, University Hospitals of Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - A Labani
- Department of Radiology, Nouvel Hôpital Civil, University Hospitals of Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - S El Ghannudi
- Department of Radiology, Nouvel Hôpital Civil, University Hospitals of Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France
| | - C Roy
- Department of Radiology, Nouvel Hôpital Civil, University Hospitals of Strasbourg, 1, place de l'Hôpital, 67000 Strasbourg, France
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Optimization of dual-energy xenon-computed tomography for quantitative assessment of regional pulmonary ventilation. Invest Radiol 2014; 48:629-37. [PMID: 23571834 DOI: 10.1097/rli.0b013e31828ad647] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE Dual-energy x-ray computed tomography (DECT) offers visualization of the airways and quantitation of regional pulmonary ventilation using a single breath of inhaled xenon gas. In this study, we sought to optimize scanning protocols for DECT xenon gas ventilation imaging of the airways and lung parenchyma and to characterize the quantitative nature of the developed protocols through a series of test-object and animal studies. MATERIALS AND METHODS The Institutional Animal Care and Use Committee approved all animal studies reported here. A range of xenon/oxygen gas mixtures (0%, 20%, 25%, 33%, 50%, 66%, 100%; balance oxygen) were scanned in syringes and balloon test-objects to optimize the delivered gas mixture for assessment of regional ventilation while allowing for the development of improved 3-material decomposition calibration parameters. In addition, to alleviate gravitational effects on xenon gas distribution, we replaced a portion of the oxygen in the xenon/oxygen gas mixture with helium and compared gas distributions in a rapid-prototyped human central-airway test-object. Additional syringe tests were performed to determine if the introduction of helium had any effect on xenon quantitation. Xenon gas mixtures were delivered to anesthetized swine to assess airway and lung parenchymal opacification while evaluating various DECT scan acquisition settings. RESULTS Attenuation curves for xenon were obtained from the syringe test-objects and were used to develop improved 3-material decomposition parameters (Hounsfield unit enhancement per percentage xenon: within the chest phantom, 2.25 at 80 kVp, 1.7 at 100 kVp, and 0.76 at 140 kVp with tin filtration; in open air, 2.5 at 80 kVp, 1.95 at 100 kVp, and 0.81 at 140 kVp with tin filtration). The addition of helium improved the distribution of xenon gas to the gravitationally nondependent portion of the airway tree test-object, while not affecting the quantitation of xenon in the 3-material decomposition DECT. The mixture 40% Xe/40% He/20% O2 provided good signal-to-noise ratio (SNR), greater than the Rose criterion (SNR > 5), while avoiding gravitational effects of similar concentrations of xenon in a 60% O2 mixture. Compared with 100/140 Sn kVp, 80/140 Sn kVp (Sn = tin filtered) provided improved SNR in a swine with an equivalent thoracic transverse density to a human subject with a body mass index of 33 kg/m. Airways were brighter in the 80/140 Sn kVp scan (80/140 Sn, 31.6%; 100/140 Sn, 25.1%) with considerably lower noise (80/140 Sn, coefficient of variation of 0.140; 100/140 Sn, coefficient of variation of 0.216). CONCLUSION To provide a truly quantitative measure of regional lung function with xenon-DECT, the basic protocols and parameter calibrations need to be better understood and quantified. It is critically important to understand the fundamentals of new techniques to allow for proper implementation and interpretation of their results before widespread usage. With the use of an in-house derived xenon calibration curve for 3-material decomposition rather than the scanner supplied calibration and a xenon/helium/oxygen mixture, we demonstrate highly accurate quantitation of xenon gas volumes and avoid gravitational effects on gas distribution. This study provides a foundation for other researchers to use and test these methods with the goal of clinical translation.
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Xenon-Enhanced Dual-Energy CT Lung Ventilation Imaging: Techniques and Clinical Applications. AJR Am J Roentgenol 2014; 202:309-17. [PMID: 24450670 DOI: 10.2214/ajr.13.11191] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Halaweish AF, Moon RE, Foster WM, Soher BJ, McAdams HP, MacFall JR, Ainslie MD, MacIntyre NR, Charles HC. Perfluoropropane gas as a magnetic resonance lung imaging contrast agent in humans. Chest 2014; 144:1300-1310. [PMID: 23722696 DOI: 10.1378/chest.12-2597] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Fluorine-enhanced MRI is a relatively inexpensive and straightforward technique that facilitates regional assessments of pulmonary ventilation. In this report, we assess its suitability through the use of perfluoropropane (PFP) in a cohort of human subjects with normal lungs and subjects with lung disease. METHODS Twenty-eight subjects between the ages of 18 and 71 years were recruited for imaging and were classified based on spirometry findings and medical history. Imaging was carried out on a Siemens TIM Trio 3T MRI scanner using two-dimensional, gradient echo, fast low-angle shot and three-dimensional gradient echo, volumetric, interpolated, breath-hold examination sequences for proton localizers and PFP functional scans, respectively. Respiratory waveforms and physiologic signals of interest were monitored throughout the imaging sessions. A region-growing algorithm was applied to the proton localizers to define the lung field of view for analysis of the PFP scans. RESULTS All subjects tolerated the gas mixture well with no adverse side effects. Images of healthy lungs demonstrated a homogeneous distribution of the gas with sufficient signal-to-noise ratios, while lung images from asthmatic and emphysematous lungs demonstrated increased heterogeneity and ventilation defects. CONCLUSIONS Fluorine-enhanced MRI using a normoxic PFP gas mixture is a well-tolerated, radiation-free technique for regionally assessing pulmonary ventilation. The inherent physical characteristics and applicability of the gaseous agent within a magnetic resonance setting facilitated a clear differentiation between normal and diseased lungs.
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Affiliation(s)
- Ahmed F Halaweish
- Department of Radiology, Durham NC; Department of Radiology, Duke Image Analysis Laboratory, Duke University School of Medicine, Durham NC
| | - Richard E Moon
- Department of Medicine, Division of Pulmonary Medicine, Durham NC; Department of Anesthesiology, GVTU Division, Durham NC
| | - W Michael Foster
- Department of Medicine, Division of Pulmonary Medicine, Durham NC
| | | | - H Page McAdams
- Department of Radiology, Division of Chest Radiology, Durham NC
| | | | - Maureen D Ainslie
- Department of Radiology, Durham NC; Department of Radiology, Duke Image Analysis Laboratory, Duke University School of Medicine, Durham NC
| | - Neil R MacIntyre
- Department of Medicine, Division of Pulmonary Medicine, Durham NC
| | - H Cecil Charles
- Department of Radiology, Durham NC; Department of Radiology, Duke Image Analysis Laboratory, Duke University School of Medicine, Durham NC.
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23
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Six JS, Hughes-Riley T, Lilburn DM, Dorkes AC, Stupic KF, Shaw DE, Morris PG, Hall IP, Pavlovskaya GE, Meersmann T. Pulmonary MRI contrast using Surface Quadrupolar Relaxation (SQUARE) of hyperpolarized (83)Kr. Magn Reson Imaging 2014; 32:48-53. [PMID: 24144493 PMCID: PMC3898897 DOI: 10.1016/j.mri.2013.08.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2013] [Revised: 08/08/2013] [Accepted: 08/20/2013] [Indexed: 11/24/2022]
Abstract
Hyperpolarized (83)Kr has previously been demonstrated to enable MRI contrast that is sensitive to the chemical composition of the surface in a porous model system. Methodological advances have lead to a substantial increase in the (83)Kr hyperpolarization and the resulting signal intensity. Using the improved methodology for spin exchange optical pumping of isotopically enriched (83)Kr, internal anatomical details of ex vivo rodent lung were resolved with hyperpolarized (83)Kr MRI after krypton inhalation. Different (83)Kr relaxation times were found between the main bronchi and the parenchymal regions in ex vivo rat lungs. The T1 weighted hyperpolarized (83)Kr MRI provided a first demonstration of surface quadrupolar relaxation (SQUARE) pulmonary MRI contrast.
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Affiliation(s)
- Joseph S. Six
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - Theodore Hughes-Riley
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - David M.L. Lilburn
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - Alan C. Dorkes
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Karl F. Stupic
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - Dominick E. Shaw
- Nottingham Respiratory Research Unit, University of Nottingham, Nottingham NG5 1PB, UK
| | - Peter G. Morris
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD, UK
| | - Ian P. Hall
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - Galina E. Pavlovskaya
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
| | - Thomas Meersmann
- Sir Peter Mansfield Magnetic Resonance Centre, University of Nottingham, Nottingham NG7 2RD, UK
- School of Medicine, University of Nottingham, Nottingham NG7 2UH, UK
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Abstract
Pulmonary emphysema is a pathologic condition characterized by permanently enlarged airspaces distal to the terminal bronchiole with destruction of the alveolar walls. Functional information of the lungs is important to understand the pathophysiology of emphysema and that of chronic obstructive pulmonary disease. With the recent developments in magnetic resonance imaging (MRI) techniques, functional MRI with variable MR sequences can be used for the evaluation of different physiological and anatomic changes seen in cases of pulmonary emphysema. In this review article, we will focus on a brief description of each method, results of some of the most recent work, and the clinical application of such knowledge.
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25
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Dual-energy lung perfusion and ventilation CT in children. Pediatr Radiol 2013; 43:298-307. [PMID: 23417255 DOI: 10.1007/s00247-012-2465-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Accepted: 07/09/2012] [Indexed: 12/13/2022]
Abstract
Dual-energy thoracic CT provides two key insights into lung physiology, i.e. regional perfusion and ventilation, and has been actively investigated to find clinically relevant applications since the introduction of dual-source CT. This functional information provided by dual-energy thoracic CT is supplementary because high-resolution thoracic anatomy is entirely preserved on dual-energy thoracic CT. In addition, virtual non-contrast imaging can omit pre-contrast scanning. In this respect, dual-energy CT imaging technique is at least dose-neutral, which is a critical requirement for paediatric imaging. In this review, imaging protocols, analysis methods, clinical applications and diagnostic pitfalls of dual-energy thoracic CT for evaluating lung perfusion and ventilation in children are described.
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Meinel FG, Graef A, Thieme SF, Bamberg F, Schwarz F, Sommer WH, Helck AD, Neurohr C, Reiser MF, Johnson TR. Assessing Pulmonary Perfusion in Emphysema. Invest Radiol 2013; 48:79-85. [DOI: 10.1097/rli.0b013e3182778f07] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Abstract
OBJECTIVE The introduction of dual-energy CT (DECT) has ushered in the ability of material differentiation and tissue characterization beyond the traditional CT attenuation scale. This quality has been exploited for visualizing and quantifying the specific tissue content using radiographic contrast agents, such as iodine-based contrast media or inhaled xenon gas. Applications of this paradigm in the thorax include characterization of the pulmonary blood pool in the setting of acute or chronic pulmonary embolism (PE) and characterization of diseases of the lung parenchyma. Selective xenon detection is being explored for imaging of lung ventilation. In addition, the usefulness of DECT-based selective iodine uptake measurements has been described for the diagnosis and surveillance of thoracic malignancies. This article reviews the current applications of DECT-based imaging techniques in the chest with an emphasis on the diagnosis and characterization of pulmonary thromboembolic disorders. CONCLUSION DECT can provide both anatomic and functional information about the lungs in a variety of pulmonary disease states based on a single contrast-enhanced CT examination. This quality has been shown to improve the diagnosis of acute and chronic PEs, other vascular disorders, lung malignancies, and parenchymal diseases. Further developments in DECT techniques and CT scanner technology will further foster and enhance the utility of this application and open new avenues in lung imaging.
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