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Peiffer C, Brombal L, Maughan Jones CJ, Arfelli F, Astolfo A, Dreossi D, Endrizzi M, Hagen CK, Mazzolani A, Menk R, Rigon L, Olivo A, Munro PRT. On the equivalence of the X-ray scattering retrieval with beam tracking and analyser-based imaging using a synchrotron source. JOURNAL OF PHYSICS D: APPLIED PHYSICS 2023; 56:45LT02. [PMID: 37601626 PMCID: PMC10437003 DOI: 10.1088/1361-6463/acee8c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 07/25/2023] [Accepted: 08/09/2023] [Indexed: 08/22/2023]
Abstract
X-ray phase contrast imaging (XPCI) methods give access to contrast mechanisms that are based on the refractive properties of matter on top of the absorption coefficient in conventional x-ray imaging. Ultra small angle x-ray scattering (USAXS) is a phase contrast mechanism that arises due to multiple refraction events caused by physical features of a scale below the physical resolution of the used imaging system. USAXS contrast can therefore give insight into subresolution structural information, which is an ongoing research topic in the vast field of different XPCI techniques. In this study, we quantitatively compare the USAXS signal retrieved by the beam tracking XPCI technique with the gold standard of the analyzer based imaging XPCI technique using a synchrotron x-ray source. We find that, provided certain conditions are met, the two methods measure the same quantity.
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Affiliation(s)
- C Peiffer
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - L Brombal
- Department of Physics, University of Trieste, Via Valerio 2, 34127 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy
| | - C J Maughan Jones
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - F Arfelli
- Department of Physics, University of Trieste, Via Valerio 2, 34127 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy
| | - A Astolfo
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - D Dreossi
- Elettra Sincrotrone Trieste SCpA, S. S. 14 km 163.5, 34012 Basovizza (TS), Italy
| | - M Endrizzi
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - C K Hagen
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - A Mazzolani
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - R Menk
- Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy
- Elettra Sincrotrone Trieste SCpA, S. S. 14 km 163.5, 34012 Basovizza (TS), Italy
- Department of Computer and Electrical Engineering, Midsweden University, Sundsvall, Sweden
| | - L Rigon
- Department of Physics, University of Trieste, Via Valerio 2, 34127 Trieste, Italy
- Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, Via Valerio 2, 34127 Trieste, Italy
| | - A Olivo
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
| | - P R T Munro
- Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, WC1E 6BT London, United Kingdom
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Tang R, Chen Y, Yan F, Chen KM. Phase Retrieval-Based Phase-Contrast Imaging and CT of Living Zebrafish. Zebrafish 2023. [PMID: 37023400 DOI: 10.1089/zeb.2022.0067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/08/2023] Open
Abstract
Zebrafish are widely used as experimental animal models. They are small and move fast in the water. Real-time imaging of fast-moving zebrafish is a challenge, and it requires that the imaging technique has higher spatiotemporal resolution and penetration ability. The purpose of this study was to evaluate the feasibility of dynamic phase retrieval (PR)-based phase-contrast imaging (PCI) for real-time displaying of the breathing and swimming process in unanesthetized free-moving zebrafish, and to evaluate the feasibility of PR-based phase-contrast CT (PCCT) for visualizing the soft tissues in anesthetized living zebrafish. PR was performed using the phase-attenuation duality (PAD) method with the δ/β values (PAD property) of 100 and 1000 for dynamic PR-based PCI and PR-based PCCT, respectively. The contrast-to-noise ratio (CNR) was used for quantitatively assessing the visibility of the adipose tissue and muscle tissue. The skeleton and swim bladder chambers in fast-moving zebrafish were clearly shown. The dynamic processes of breathing and swimming were visibly recorded. The respiratory intensity and frequency and the movement flexibility of the zebrafish could be dynamically evaluated. By producing more obvious image contrast, PR-based PCCT clearly showed the adipose tissue and muscle tissue. The CNRs from PR-based PCCT were significantly higher than those from PR-free PCCT for both adipose tissue (9.256 ± 2.037 vs. 0.429 ± 0.426, p < 0.0001) and muscle tissue (7.095 ± 1.443 vs. 0.324 ± 0.267, p < 0.0001). Dynamic PR-based PCI holds the potential for investigating both morphological abnormalities and motor disorders. PR-based PCCT offers clear visualization and the potential for quantification of soft tissues in living zebrafish.
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Affiliation(s)
- Rongbiao Tang
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Yi Chen
- Shanghai Institute of Hematology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Ke-Min Chen
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
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Olivo A. Edge-illumination x-ray phase-contrast imaging. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:363002. [PMID: 34167096 PMCID: PMC8276004 DOI: 10.1088/1361-648x/ac0e6e] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/07/2021] [Accepted: 06/24/2021] [Indexed: 05/08/2023]
Abstract
Although early demonstration dates back to the mid-sixties, x-ray phase-contrast imaging (XPCI) became hugely popular in the mid-90s, thanks to the advent of 3rd generation synchrotron facilities. Its ability to reveal object features that had so far been considered invisible to x-rays immediately suggested great potential for applications across the life and the physical sciences, and an increasing number of groups worldwide started experimenting with it. At that time, it looked like a synchrotron facility was strictly necessary to perform XPCI with some degree of efficiency-the only alternative being micro-focal sources, the limited flux of which imposed excessively long exposure times. However, new approaches emerged in the mid-00s that overcame this limitation, and allowed XPCI implementations with conventional, non-micro-focal x-ray sources. One of these approaches showing particular promise for 'real-world' applications is edge-illumination XPCI: this article describes the key steps in its evolution in the context of contemporary developments in XPCI research, and presents its current state-of-the-art, especially in terms of transition towards practical applications.
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Affiliation(s)
- Alessandro Olivo
- Department of Medical Physics and Biomedical Engineering, UCL, London, United Kingdom
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Tang R, Li Y, Qin L, Yan F, Yang GY, Chen KM. Phase retrieval-based phase-contrast CT for vascular imaging with microbubble contrast agent. Med Phys 2021; 48:3459-3469. [PMID: 33657645 DOI: 10.1002/mp.14819] [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: 11/10/2020] [Revised: 02/15/2021] [Accepted: 02/23/2021] [Indexed: 11/11/2022] Open
Abstract
PURPOSE The introduction of microbubble contrast agent into tissues can create significant phase shifts. Phase retrieval (PR)-based phase-contrast computed tomography (PCCT) is an imaging method for retrieving and reconstructing the phase shifts within an object. This study aimed to evaluate the feasibility of PR-based PCCT with microbubble contrast agent for vascular imaging. METHODS Projection phase-contrast images of individual microbubbles and a cluster of microbubbles were captured and compared. Contrast enhancement from microbubbles was evaluated by comparing to the gold standard iodine-based contrast agent in vitro. The arterial systems of 14 Sprague-Dawley rats were perfused with microbubbles or saline. The rat hearts and the arterial systems were excised and imaged ex vivo. CT imaging was performed at the energy of 22 keV. PR was performed using the phase-attenuation duality (PAD) method with different δ/β values (PAD property). The contrast-to-noise ratio (CNR) was used for quantitatively assessing the contrast enhancement. RESULTS Individual microbubbles functioned as a lens to focus the x rays, whereas, a cluster of microbubbles scattered the x rays. In the in vitro experiment, the contrast enhancement from iodine was significantly greater than that from microbubbles (P < 0.05). In the heart samples, the CNRs for microbubbles on PR-based PCCT were significantly greater than those on absorption-contrast CT (ACCT) and PR-free PCCT (both P < 0.001). The CNRs for microbubbles were also significantly greater than those for saline on PR-based PCCT in the samples (P < 0.001). Although they provided weaker contrast enhancement than that from iodine, microbubbles could still provide sufficient contrast enhancement to clearly show the 3D architecture of rat aortas and their main branches. CONCLUSION The imaging modality can currently be used as a complement or alternative to absorption-based microCT for imaging vessels in biological samples.
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Affiliation(s)
- Rongbiao Tang
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Yongfang Li
- Department of Neurology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Le Qin
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Fuhua Yan
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
| | - Guo-Yuan Yang
- Med-X Research Institute and School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Ke-Min Chen
- Department of Radiology, Rui Jin Hospital, Shanghai Jiao Tong University, and School of Medicine, Shanghai, China
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Sellerer T, Mechlem K, Tang R, Taphorn KA, Pfeiffer F, Herzen J. Dual-Energy X-Ray Dark-Field Material Decomposition. IEEE TRANSACTIONS ON MEDICAL IMAGING 2021; 40:974-985. [PMID: 33290214 DOI: 10.1109/tmi.2020.3043303] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Dual-energy imaging is a clinically well-established technique that offers several advantages over conventional X-ray imaging. By performing measurements with two distinct X-ray spectra, differences in energy-dependent attenuation are exploited to obtain material-specific information. This information is used in various imaging applications to improve clinical diagnosis. In recent years, grating-based X-ray dark-field imaging has received increasing attention in the imaging community. The X-ray dark-field signal originates from ultra small-angle scattering within an object and thus provides information about the microstructure far below the spatial resolution of the imaging system. This property has led to a number of promising future imaging applications that are currently being investigated. However, different microstructures can hardly be distinguished with current X-ray dark-field imaging techniques, since the detected dark-field signal only represents the total amount of ultra small-angle scattering. To overcome these limitations, we present a novel concept called dual-energy X-ray dark-field material decomposition, which transfers the basic material decomposition approach from attenuation-based dual-energy imaging to the dark-field imaging modality. We develop a physical model and algorithms for dual-energy dark-field material decomposition and evaluate the proposed concept in experimental measurements. Our results suggest that by sampling the energy-dependent dark-field signal with two different X-ray spectra, a decomposition into two different microstructured materials is possible. Similar to dual-energy imaging, the additional microstructure-specific information could be useful for clinical diagnosis.
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Andrejewski J, De Marco F, Willer K, Noichl W, Gustschin A, Koehler T, Meyer P, Kriner F, Fischer F, Braun C, Fingerle AA, Herzen J, Pfeiffer F, Pfeiffer D. Whole-body x-ray dark-field radiography of a human cadaver. Eur Radiol Exp 2021; 5:6. [PMID: 33495889 PMCID: PMC7835263 DOI: 10.1186/s41747-020-00201-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 12/03/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Grating-based x-ray dark-field and phase-contrast imaging allow extracting information about refraction and small-angle scatter, beyond conventional attenuation. A step towards clinical translation has recently been achieved, allowing further investigation on humans. METHODS After the ethics committee approval, we scanned the full body of a human cadaver in anterior-posterior orientation. Six measurements were stitched together to form the whole-body image. All radiographs were taken at a three-grating large-object x-ray dark-field scanner, each lasting about 40 s. Signal intensities of different anatomical regions were assessed. The magnitude of visibility reduction caused by beam hardening instead of small-angle scatter was analysed using different phantom materials. Maximal effective dose was 0.3 mSv for the abdomen. RESULTS Combined attenuation and dark-field radiography are technically possible throughout a whole human body. High signal levels were found in several bony structures, foreign materials, and the lung. Signal levels were 0.25 ± 0.13 (mean ± standard deviation) for the lungs, 0.08 ± 0.06 for the bones, 0.023 ± 0.019 for soft tissue, and 0.30 ± 0.02 for an antibiotic bead chain. We found that phantom materials, which do not produce small-angle scatter, can generate a strong visibility reduction signal. CONCLUSION We acquired a whole-body x-ray dark-field radiograph of a human body in few minutes with an effective dose in a clinical acceptable range. Our findings suggest that the observed visibility reduction in the bone and metal is dominated by beam hardening and that the true dark-field signal in the lung is therefore much higher than that of the bone.
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Affiliation(s)
- Jana Andrejewski
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.
| | - Fabio De Marco
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Konstantin Willer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Wolfgang Noichl
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Alex Gustschin
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | | | - Pascal Meyer
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Fabian Kriner
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Florian Fischer
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Christian Braun
- Institut für Rechtsmedizin, Ludwig-Maximilians-Universität München, 80336, Munich, Germany
| | - Alexander A Fingerle
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, 81675, Munich, Germany
| | - Julia Herzen
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics and Munich School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Technical University of Munich, 81675, Munich, Germany
| | - Daniela Pfeiffer
- Department of Diagnostic and Interventional Radiology, Technical University of Munich, 81675, Munich, Germany
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Notohamiprodjo S, Varasteh Z, Beer AJ, Niu G, Chen X(S, Weber W, Schwaiger M. Tumor Vasculature. Mol Imaging 2021. [DOI: 10.1016/b978-0-12-816386-3.00090-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022] Open
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Notohamiprodjo S, Treitl KM, Hauke C, Sutter SM, Auweter S, Pfeiffer F, Reiser MF, Hellbach K. Imaging characteristics of intravascular spherical contrast agents for grating-based x-ray dark-field imaging – effects of concentrations, spherical sizes and applied voltage. Sci Rep 2020; 10:9405. [PMID: 32523085 PMCID: PMC7287139 DOI: 10.1038/s41598-020-66395-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Accepted: 05/14/2020] [Indexed: 11/09/2022] Open
Abstract
AbstractThis study investigates the x-ray scattering characteristics of microsphere particles in x-ray-grating-based interferometric imaging at different concentrations, bubble sizes and tube voltages (kV). Attenuation (ATI), dark-field (DFI) and phase-contrast (PCI) images were acquired. Signal-to-noise (SNR) and contrast-to-noise ratios with water (CNRw) and air as reference (CNRa) were determined. In all modalities, a linear relationship between SNR and microbubbles concentration, respectively, microsphere size was found. A significant gain of SNR was found when varying kV. SNR was significantly higher in DFI and PCI than ATI. The highest gain of SNR was shown at 60 kV for all media in ATI and DFI, at 80 kV for PCI. SNR for all media was significantly higher compared to air and was slightly lower compared to water. A linear relationship was found between CNRa, CNRw, concentration and size. With increasing concentration and decreasing size, CNRa and CNRw increased in DFI, but decreased in PCI. Best CNRa and CNRw was found at specific combination of kV and concentration/size. Highest average CNRa and CNRw was found for microspheres in ATI and PCI, for microbubbles in DFI. Microspheres are a promising contrast-media for grating-based-interferometry, if kV, microsphere size and concentration are appropriately combined.
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Ton N, Goncin U, Panahifar A, Chapman D, Wiebe S, Machtaler S. Developing a Microbubble-Based Contrast Agent for Synchrotron In-Line Phase Contrast Imaging. IEEE Trans Biomed Eng 2020; 68:1527-1535. [PMID: 33232220 DOI: 10.1109/tbme.2020.3040079] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
OBJECTIVE X-ray phase contrast imaging generates contrast from refraction of X-rays, enhancing soft tissue contrast compared to conventional absorption-based imaging. Our goal is to develop a contrast agent for X-ray in-line phase contrast imaging (PCI) based on ultrasound microbubbles (MBs), by assessing size, shell material, and concentration. METHODS Polydisperse perfluorobutane-core lipid-shelled MBs were synthesized and size separated into five groups between 1 and 10 μm. We generated two size populations of polyvinyl-alcohol (PVA)-MBs, 2-3 μm and 3-4 μm, whose shells were either coated or integrated with iron oxide nanoparticles (SPIONs). Microbubbles were then embedded in agar at three concentrations: 5 × 107, 5 × 106 and 5 × 105 MBs/ml. In-line phase contrast imaging was performed at the Canadian Light Source with filtered white beam micro-computed tomography. Phase contrast intensity was measured by both counting detectable MBs, and comparing mean pixel values (MPV) in minimum and maximum intensity projections of the overall samples. RESULTS Individual lipid-MBs 6-10 μm, lipid-MBs 4-6 μm and PVA-MBs coated with SPIONs were detectable at each concentration. At the highest concentration, lipid-MBs 6-10 μm and 4-6 μm showed an overall increase in positive contrast, whereas at a moderate concentration, only lipid-MBs 6-10 μm displayed an increase. Negative contrast was also observed from two largest lipid-MBs at high concentration. CONCLUSION These data indicate that lipid-MBs larger than 4 μm are candidates for PCI, and 5 × 106 MBs/ml may be the lowest concentration suitable for generating visible phase contrast in vivo. SIGNIFICANCE Identifying a suitable MB for PCI may facilitate future clinical translation.
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Abstract
Unlike conventional x-ray attenuation one of the advantages of phase contrast x-ray imaging is its capability of extracting useful physical properties of the sample. In particular the possibility to obtain information from small angle scattering about unresolvable structures with sub-pixel resolution sensitivity has drawn attention for both medical and material science applications. We report on a novel algorithm for the analyzer based x-ray phase contrast imaging modality, which allows the robust separation of absorption, refraction and scattering effects from three measured x-ray images. This analytical approach is based on a simple Gaussian description of the analyzer transmission function and this method is capable of retrieving refraction and small angle scattering angles in the full angular range typical of biological samples. After a validation of the algorithm with a simulation code, which demonstrated the potential of this highly sensitive method, we have applied this theoretical framework to experimental data on a phantom and biological tissues obtained with synchrotron radiation. Owing to its extended angular acceptance range the algorithm allows precise assessment of local scattering distributions at biocompatible radiation doses, which in turn might yield a quantitative characterization tool with sufficient structural sensitivity on a submicron length scale.
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Wu D, Wong MD, Li Y, Fajardo L, Zheng B, Wu X, Liu H. Quantitative investigation of the edge enhancement in in-line phase contrast projections and tomosynthesis provided by distributing microbubbles on the interface between two tissues: a phantom study. Phys Med Biol 2017; 62:9357-9376. [PMID: 29161236 PMCID: PMC5731655 DOI: 10.1088/1361-6560/aa9548] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The objective of this study was to quantitatively investigate the ability to distribute microbubbles along the interface between two tissues, in an effort to improve the edge and/or boundary features in phase contrast imaging. The experiments were conducted by employing a custom designed tissue simulating phantom, which also simulated a clinical condition where the ligand-targeted microbubbles are self-aggregated on the endothelium of blood vessels surrounding malignant cells. Four different concentrations of microbubble suspensions were injected into the phantom: 0%, 0.1%, 0.2%, and 0.4%. A time delay of 5 min was implemented before image acquisition to allow the microbubbles to become distributed at the interface between the acrylic and the cavity simulating a blood vessel segment. For comparison purposes, images were acquired using three system configurations for both projection and tomosynthesis imaging with a fixed radiation dose delivery: conventional low-energy contact mode, low-energy in-line phase contrast and high-energy in-line phase contrast. The resultant images illustrate the edge feature enhancements in the in-line phase contrast imaging mode when the microbubble concentration is extremely low. The quantitative edge-enhancement-to-noise ratio calculations not only agree with the direct image observations, but also indicate that the edge feature enhancement can be improved by increasing the microbubble concentration. In addition, high-energy in-line phase contrast imaging provided better performance in detecting low-concentration microbubble distributions.
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Affiliation(s)
- Di Wu
- School of Electrical and Computer Engineering, University of Oklahoma, 110 West Boyd Street, Norman, OK 73019, United States of America
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Wu D, Wong MD, Yang K, Yan A, Li Y, Fajardo L, Zheng B, Wu X, Liu H. Using Microbubble as Contrast Agent for High-Energy X-Ray In-line Phase Contrast Imaging: Demonstration and Comparison Study. IEEE Trans Biomed Eng 2017; 65:1117-1123. [PMID: 28829304 DOI: 10.1109/tbme.2017.2741942] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The ability of microbubbles to benefit the imaging quality of high-energy in-line phase contrast as compared with conventional low-energy contact mode radiography was investigated. The study was conducted by comparing in-line phase contrast imaging with conventional contact-mode projection imaging under the same dose delivered to a phantom. A custom-designed phantom was employed to simulate a segment of human blood vessel injected with microbubble suspensions. The microbubbles were suspended in deionized water to obtain different volume concentrations. The area contrast-to-noise ratio (CNR) values corresponding to both imaging methods were measured for different microbubble volume concentrations. The phase contrast images were processed by phase-attenuation duality phase retrieval to preserve the imaging quality. Comparison of the resultant CNR values indicates that the microbubble suspension images deliver a higher CNR than the water-only image, with monotonically increasing trends between the CNR values and microbubble concentrations. Compared to low-energy conventional images of the microbubble suspensions, high-energy in-line phase contrast CNRs are lower at high concentrations and are comparable, even better than, at low concentrations. This result suggests that 1) the performance of copolymer-shell microbubble employed in this study as x-ray contrast agent is constrained by the detective quantum efficiency of the system and the attenuation properties of the shell materials, 2) the phase-attenuation duality phase retrieval method has the potential to preserve image quality for areas with low concentration of microbubbles, and 3) the selection of microbubble products as a phase contrast agent may follow criteria of minimizing the impact of absorption attenuation properties of the shells and maximizing the difference factor of electron densities.
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Gromann LB, De Marco F, Willer K, Noël PB, Scherer K, Renger B, Gleich B, Achterhold K, Fingerle AA, Muenzel D, Auweter S, Hellbach K, Reiser M, Baehr A, Dmochewitz M, Schroeter TJ, Koch FJ, Meyer P, Kunka D, Mohr J, Yaroshenko A, Maack HI, Pralow T, van der Heijden H, Proksa R, Koehler T, Wieberneit N, Rindt K, Rummeny EJ, Pfeiffer F, Herzen J. In-vivo X-ray Dark-Field Chest Radiography of a Pig. Sci Rep 2017; 7:4807. [PMID: 28684858 PMCID: PMC5500502 DOI: 10.1038/s41598-017-05101-w] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Accepted: 05/25/2017] [Indexed: 12/12/2022] Open
Abstract
X-ray chest radiography is an inexpensive and broadly available tool for initial assessment of the lung in clinical routine, but typically lacks diagnostic sensitivity for detection of pulmonary diseases in their early stages. Recent X-ray dark-field (XDF) imaging studies on mice have shown significant improvements in imaging-based lung diagnostics. Especially in the case of early diagnosis of chronic obstructive pulmonary disease (COPD), XDF imaging clearly outperforms conventional radiography. However, a translation of this technique towards the investigation of larger mammals and finally humans has not yet been achieved. In this letter, we present the first in-vivo XDF full-field chest radiographs (32 × 35 cm2) of a living pig, acquired with clinically compatible parameters (40 s scan time, approx. 80 µSv dose). For imaging, we developed a novel high-energy XDF system that overcomes the limitations of currently established setups. Our XDF radiographs yield sufficiently high image quality to enable radiographic evaluation of the lungs. We consider this a milestone in the bench-to-bedside translation of XDF imaging and expect XDF imaging to become an invaluable tool in clinical practice, both as a general chest X-ray modality and as a dedicated tool for high-risk patients affected by smoking, industrial work and indoor cooking.
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Affiliation(s)
- Lukas B Gromann
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.
| | - Fabio De Marco
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Konstantin Willer
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Peter B Noël
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Kai Scherer
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Bernhard Renger
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Bernhard Gleich
- Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Klaus Achterhold
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany
| | - Alexander A Fingerle
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Daniela Muenzel
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Sigrid Auweter
- Institute of Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, 81377, Munich, Germany
| | - Katharina Hellbach
- Institute of Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, 81377, Munich, Germany
| | - Maximilian Reiser
- Institute of Clinical Radiology, Ludwig-Maximilian-University Hospital Munich, 81377, Munich, Germany
| | - Andrea Baehr
- Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilian-University, 85764, Oberschleißheim, Germany
| | - Michaela Dmochewitz
- Institute of Molecular Animal Breeding and Biotechnology, Ludwig-Maximilian-University, 85764, Oberschleißheim, Germany
| | - Tobias J Schroeter
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Frieder J Koch
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Pascal Meyer
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Danays Kunka
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Juergen Mohr
- Institute of Microstructure Technology, Karlsruhe Institute of Technology, 76344, Eggenstein-Leopoldshafen, Germany
| | - Andre Yaroshenko
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.,Philips Medical Systems DMC GmbH, 22335, Hamburg, Germany
| | | | - Thomas Pralow
- Philips Medical Systems DMC GmbH, 22335, Hamburg, Germany
| | | | - Roland Proksa
- Philips GmbH Innovative Technologies, Research Laboratories, 22335, Hamburg, Germany
| | - Thomas Koehler
- Philips GmbH Innovative Technologies, Research Laboratories, 22335, Hamburg, Germany.,Institute for Advanced Study, Technical University of Munich, 85748, Garching, Germany
| | | | - Karsten Rindt
- Philips Medical Systems DMC GmbH, 22335, Hamburg, Germany
| | - Ernst J Rummeny
- Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.,Department of Diagnostic and Interventional Radiology, Klinikum rechts der Isar, Technical University of Munich, 81675, München, Germany.,Institute for Advanced Study, Technical University of Munich, 85748, Garching, Germany
| | - Julia Herzen
- Chair of Biomedical Physics & Institute of Medical Engineering, Technical University of Munich, 85748, Garching, Germany.
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14
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Scherer K, Yaroshenko A, Bölükbas DA, Gromann LB, Hellbach K, Meinel FG, Braunagel M, Berg JV, Eickelberg O, Reiser MF, Pfeiffer F, Meiners S, Herzen J. X-ray Dark-field Radiography - In-Vivo Diagnosis of Lung Cancer in Mice. Sci Rep 2017; 7:402. [PMID: 28341830 PMCID: PMC5428469 DOI: 10.1038/s41598-017-00489-x] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Accepted: 02/28/2017] [Indexed: 02/01/2023] Open
Abstract
Accounting for about 1.5 million deaths annually, lung cancer is the prevailing cause of cancer deaths worldwide, mostly associated with long-term smoking effects. Numerous small-animal studies are performed currently in order to better understand the pathogenesis of the disease and to develop treatment strategies. Within this letter, we propose to exploit X-ray dark-field imaging as a novel diagnostic tool for the detection of lung cancer on projection radiographs. Here, we demonstrate in living mice bearing lung tumors, that X-ray dark-field radiography provides significantly improved lung tumor detection rates without increasing the number of false-positives, especially in the case of small and superimposed nodules, when compared to conventional absorption-based imaging. While this method still needs to be adapted to larger mammals and finally humans, the technique presented here can already serve as a valuable tool in evaluating novel lung cancer therapies, tested in mice and other small animal models.
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Affiliation(s)
- Kai Scherer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany.
| | - Andre Yaroshenko
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
- Philips Medical Systems DMC GmbH, 22335, Hamburg, Germany
| | - Deniz Ali Bölükbas
- Comprehensive Pneumology Center (CPC), University Hospital, Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Lukas B Gromann
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
| | - Katharina Hellbach
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Felix G Meinel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Margarita Braunagel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Jens von Berg
- Philips Research Laboratories, Philips Medical Systems, 22335, Hamburg, Germany
| | - Oliver Eickelberg
- Comprehensive Pneumology Center (CPC), University Hospital, Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Maximilian F Reiser
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, 81377, Munich, Germany
| | - Franz Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
| | - Silke Meiners
- Comprehensive Pneumology Center (CPC), University Hospital, Ludwig-Maximilians University, Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), 81377 Munich, Germany
| | - Julia Herzen
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, 85748, Garching, Germany
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15
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Wieczorek M, Schaff F, Pfeiffer F, Lasser T. Anisotropic X-Ray Dark-Field Tomography: A Continuous Model and its Discretization. PHYSICAL REVIEW LETTERS 2016; 117:158101. [PMID: 27768366 DOI: 10.1103/physrevlett.117.158101] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Indexed: 06/06/2023]
Abstract
The x-ray dark-field signal measured in grating interferometers is anisotropic, depending on both the beam direction and the grating orientation with respect to the sample. We present a novel general closed-form, continuous forward model of the anisotropic dark-field signal. Furthermore, we derive a discretization using spherical harmonics, leading to a large-scale linear inverse problem. We present first experimental results of a wooden sample, demonstrating marked advantages over previous results, in particular, the resolution of multiple scattering directions in one volume element.
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Affiliation(s)
- M Wieczorek
- Computer Aided Medical Procedures, Technische Universität München, 85748 Garching, Germany
| | - F Schaff
- Lehrstuhl für Biomedizinische Physik, Physik-Department and Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
| | - F Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department and Institut für Medizintechnik, Technische Universität München, 85748 Garching, Germany
- Institut für diagnostische und interventionelle Radiologie, Klinikum rechts der Isar, Technische Universität München, 81675 München, Germany
| | - T Lasser
- Computer Aided Medical Procedures, Technische Universität München, 85748 Garching, Germany
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16
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Abstract
OBJECTIVES The aim of this study was to evaluate the suitability of in vivo x-ray dark-field radiography for early-stage diagnosis of pulmonary emphysema in mice. Furthermore, we aimed to analyze how the dark-field signal correlates with morphological changes of lung architecture at distinct stages of emphysema. MATERIALS AND METHODS Female 8- to 10-week-old C57Bl/6N mice were used throughout all experiments. Pulmonary emphysema was induced by orotracheal injection of porcine pancreatic elastase (80-U/kg body weight) (n = 30). Control mice (n = 11) received orotracheal injection of phosphate-buffered saline. To monitor the temporal patterns of emphysema development over time, the mice were imaged 7, 14, or 21 days after the application of elastase or phosphate-buffered saline. X-ray transmission and dark-field images were acquired with a prototype grating-based small-animal scanner. In vivo pulmonary function tests were performed before killing the animals. In addition, lungs were obtained for detailed histopathological analysis, including mean cord length (MCL) quantification as a parameter for the assessment of emphysema. Three blinded readers, all of them experienced radiologists and familiar with dark-field imaging, were asked to grade the severity of emphysema for both dark-field and transmission images. RESULTS Histopathology and MCL quantification confirmed the introduction of different stages of emphysema, which could be clearly visualized and differentiated on the dark-field radiograms, whereas early stages were not detected on transmission images. The correlation between MCL and dark-field signal intensities (r = 0.85) was significantly higher than the correlation between MCL and transmission signal intensities (r = 0.37). The readers' visual ratings for dark-field images correlated significantly better with MCL (r = 0.85) than visual ratings for transmission images (r = 0.36). Interreader agreement and the diagnostic accuracy of both quantitative and visual assessment were significantly higher for dark-field imaging than those for conventional transmission images. CONCLUSIONS X-ray dark-field radiography can reliably visualize different stages of emphysema in vivo and demonstrates significantly higher diagnostic accuracy for early stages of emphysema than conventional attenuation-based radiography.
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17
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Molecular evaluation of thrombosis using X-ray phase contrast imaging with microbubbles targeted to P-selectin in mice. Eur Radiol 2015; 26:3253-61. [PMID: 26628067 DOI: 10.1007/s00330-015-4129-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2015] [Revised: 11/15/2015] [Accepted: 11/19/2015] [Indexed: 10/22/2022]
Abstract
OBJECTIVES X-ray phase contrast imaging (PCI) provides excellent image contrast by utilizing the phase shift. The introduction of microbubbles into tissues can cause a phase shift to make microbubbles visibly identified on PCI. In this study, we assessed the feasibility of targeted microbubble-based PCI for the detection of thrombosis. METHODS The absorption and phase contrast images of P-selectin-targeted microbubbles (MBP) were obtained and compared in vitro. MBP, control IgG-targeted microbubbles (MBC), and unbound microbubbles (MBU) were tested for binding specificity on thrombi expressing P-selectin. MBP were used as molecular PCI probes to evaluate P-selectin expression in a mouse model of arteriovenous shunt thrombosis that was created using PE tubes in the bypass outside of the mouse body. RESULTS PCI clearly showed the microbubbles not viewable via absorption contrast imaging (ACI). In vitro attachment of MBP (91.60 ± 11.63) to thrombi was significantly higher than attachment of MBC (17.80 ± 4.02, P < 0.001) or MBU (9.80 ± 2.59, P < 0.001). In the mouse model of arteriovenous shunt thrombosis, the binding affinity of MBP (15.50 ± 6.25) was significantly greater than that of MBC (0.50 ± 0.84, P < 0.001) or MBU (0.33 ± 0.52, P < 0.001). CONCLUSIONS Our results indicate that molecular PCI may be considered as a novel and promising imaging modality for the investigation of thrombosis. KEY POINTS • Small thrombi are rarely detected by conventional radiography. • Phase contrast imaging (PCI) provides higher contrast and spatial resolution than conventional radiography. • P-selectin targeted microbubbles detected by PCI may suggest early thrombosis.
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19
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Velroyen A, Yaroshenko A, Hahn D, Fehringer A, Tapfer A, Müller M, Noël PB, Pauwels B, Sasov A, Yildirim AÖ, Eickelberg O, Hellbach K, Auweter SD, Meinel FG, Reiser MF, Bech M, Pfeiffer F. Grating-based X-ray Dark-field Computed Tomography of Living Mice. EBioMedicine 2015; 2:1500-6. [PMID: 26629545 PMCID: PMC4634200 DOI: 10.1016/j.ebiom.2015.08.014] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2015] [Revised: 08/04/2015] [Accepted: 08/05/2015] [Indexed: 02/01/2023] Open
Abstract
Changes in x-ray attenuating tissue caused by lung disorders like emphysema or fibrosis are subtle and thus only resolved by high-resolution computed tomography (CT). The structural reorganization, however, is of strong influence for lung function. Dark-field CT (DFCT), based on small-angle scattering of x-rays, reveals such structural changes even at resolutions coarser than the pulmonary network and thus provides access to their anatomical distribution. In this proof-of-concept study we present x-ray in vivo DFCTs of lungs of a healthy, an emphysematous and a fibrotic mouse. The tomographies show excellent depiction of the distribution of structural – and thus indirectly functional – changes in lung parenchyma, on single-modality slices in dark field as well as on multimodal fusion images. Therefore, we anticipate numerous applications of DFCT in diagnostic lung imaging. We introduce a scatter-based Hounsfield Unit (sHU) scale to facilitate comparability of scans. In this newly defined sHU scale, the pathophysiological changes by emphysema and fibrosis cause a shift towards lower numbers, compared to healthy lung tissue. We present so far unreported x-ray scatter dark-field CT scans of living mice performed with a Talbot–Lau interferometer. Dark field gives access to structural information not provided by attenuation CT at scales below the detector pixel size. Changes of lung alveoli structure are clearly visualized by dark-field CT for emphysema and fibrosis.
Lung diseases pose one of the leading causes of death worldwide. They are often difficult to diagnose at an early stage due to low sensitivity of conventional medical imaging systems towards structural changes of the lung tissue. With dark-field imaging based on scattering of x-rays such structural changes can be visualized even at imaging system resolutions coarser than the lung alveoli, as opposed to conventional x-ray imaging based on attenuation. By overcoming experimental scan time and dose issues, we report the first dark-field computed tomography scans on living mice, demonstrating excellent depiction of the anatomical distribution of pathological lung changes.
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Affiliation(s)
- A Velroyen
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - A Yaroshenko
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - D Hahn
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - A Fehringer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - A Tapfer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - M Müller
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - P B Noël
- Department of Radiology, Technische Universität München, Munich, Germany
| | | | - A Sasov
- Bruker microCT, Kontich, Belgium
| | - A Ö Yildirim
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München and Ludwig-Maximilians-University Hospital Munich, Munich, Germany ; German Center for Lung Research (DZL), Germany
| | - O Eickelberg
- Comprehensive Pneumology Center, Institute of Lung Biology and Disease, Helmholtz Zentrum München and Ludwig-Maximilians-University Hospital Munich, Munich, Germany ; German Center for Lung Research (DZL), Germany
| | - K Hellbach
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - S D Auweter
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - F G Meinel
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - M F Reiser
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany ; German Center for Lung Research (DZL), Germany
| | - M Bech
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany ; Medical Radiation Physics, Lund University, Lund, Sweden
| | - F Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
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20
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Abstract
X-rays are commonly used as a means to image the inside of objects opaque to visible light, as their short wavelength allows penetration through matter and the formation of high spatial resolution images. This physical effect has found particular importance in medicine where x-ray based imaging is routinely used as a diagnostic tool. Increasingly, however, imaging modalities that provide functional as well as morphological information are required. In this study the potential to use x-ray phase based imaging as a functional modality through the use of microbubbles that can be targeted to specific biological processes is explored. We show that the concentration of a microbubble suspension can be monitored quantitatively whilst in flow using x-ray phase contrast imaging. This could provide the basis for a dynamic imaging technique that combines the tissue penetration, spatial resolution, and high contrast of x-ray phase based imaging with the functional information offered by targeted imaging modalities.
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21
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Velroyen A, Bech M, Tapfer A, Yaroshenko A, Müller M, Paprottka P, Ingrisch M, Cyran CC, Auweter SD, Nikolaou K, Reiser MF, Pfeiffer F. Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging. PLoS One 2015; 10:e0129512. [PMID: 26134130 PMCID: PMC4489901 DOI: 10.1371/journal.pone.0129512] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 05/08/2015] [Indexed: 12/22/2022] Open
Abstract
The investigation of dedicated contrast agents for x-ray dark-field imaging, which exploits small-angle scattering at microstructures for contrast generation, is of strong interest in analogy to the common clinical use of high-atomic number contrast media in conventional attenuation-based imaging, since dark-field imaging has proven to provide complementary information. Therefore, agents consisting of gas bubbles, as used in ultrasound imaging for example, are of particular interest. In this work, we investigate an experimental contrast agent based on microbubbles consisting of a polyvinyl-alcohol shell with an iron oxide coating, which was originally developed for multimodal imaging and drug delivery. Its performance as a possible contrast medium for small-animal angiography was examined using a mouse carcass to realistically consider attenuating and scattering background signal. Subtraction images of dark field, phase contrast and attenuation were acquired for a concentration series of 100%, 10% and 1.3% to mimic different stages of dilution in the contrast agent in the blood vessel system. The images were compared to the gold-standard iodine-based contrast agent Solutrast, showing a good contrast improvement by microbubbles in dark-field imaging. This study proves the feasibility of microbubble-based dark-field contrast-enhancement in presence of scattering and attenuating mouse body structures like bone and fur. Therefore, it suggests a strong potential of the use of polymer-based microbubbles for small-animal dark-field angiography.
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Affiliation(s)
- Astrid Velroyen
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
- * E-mail:
| | - Martin Bech
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
- Medical Radiation Physics, Lund University, Lund, Sweden
| | - Arne Tapfer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Andre Yaroshenko
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Mark Müller
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
| | - Philipp Paprottka
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Michael Ingrisch
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Clemens C. Cyran
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Sigrid D. Auweter
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Konstantin Nikolaou
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Maximilian F. Reiser
- Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Franz Pfeiffer
- Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany
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22
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Velroyen A, Bech M, Zanette I, Schwarz J, Rack A, Tympner C, Herrler T, Staab-Weijnitz C, Braunagel M, Reiser M, Bamberg F, Pfeiffer F, Notohamiprodjo M. X-ray phase-contrast tomography of renal ischemia-reperfusion damage. PLoS One 2014; 9:e109562. [PMID: 25299243 PMCID: PMC4192129 DOI: 10.1371/journal.pone.0109562] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 09/02/2014] [Indexed: 01/28/2023] Open
Abstract
Purpose The aim of the study was to investigate microstructural changes occurring in unilateral renal ischemia-reperfusion injury in a murine animal model using synchrotron radiation. Material and Methods The effects of renal ischemia-reperfusion were investigated in a murine animal model of unilateral ischemia. Kidney samples were harvested on day 18. Grating-Based Phase-Contrast Imaging (GB-PCI) of the paraffin-embedded kidney samples was performed at a Synchrotron Radiation Facility (beam energy of 19 keV). To obtain phase information, a two-grating Talbot interferometer was used applying the phase stepping technique. The imaging system provided an effective pixel size of 7.5 µm. The resulting attenuation and differential phase projections were tomographically reconstructed using filtered back-projection. Semi-automated segmentation and volumetry and correlation to histopathology were performed. Results GB-PCI provided good discrimination of the cortex, outer and inner medulla in non-ischemic control kidneys. Post-ischemic kidneys showed a reduced compartmental differentiation, particularly of the outer stripe of the outer medulla, which could not be differentiated from the inner stripe. Compared to the contralateral kidney, after ischemia a volume loss was detected, while the inner medulla mainly retained its volume (ratio 0.94). Post-ischemic kidneys exhibited severe tissue damage as evidenced by tubular atrophy and dilatation, moderate inflammatory infiltration, loss of brush borders and tubular protein cylinders. Conclusion In conclusion GB-PCI with synchrotron radiation allows for non-destructive microstructural assessment of parenchymal kidney disease and vessel architecture. If translation to lab-based approaches generates sufficient density resolution, and with a time-optimized image analysis protocol, GB-PCI may ultimately serve as a non-invasive, non-enhanced alternative for imaging of pathological changes of the kidney.
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Affiliation(s)
- Astrid Velroyen
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Martin Bech
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
- Medical Radiation Physics, Lund University, Lund, Sweden
| | - Irene Zanette
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Jolanda Schwarz
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Alexander Rack
- European Synchrotron Radiation Facility, Grenoble, France
| | - Christiane Tympner
- Institute of Pathology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Tanja Herrler
- Department of General, Trauma, Hand, and Plastic Surgery, Ludwig-Maximilians-University Hospital Munich, Munich, Germany
| | - Claudia Staab-Weijnitz
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
- Comprehensive Pneumology Center, University Hospital, Ludwig-Maximilians-University and Helmholtz Zentrum Munich, Munich, Germany
| | - Margarita Braunagel
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
| | - Maximilian Reiser
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
| | - Fabian Bamberg
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
- Department of Radiology, University Hospital Tuebingen, Tuebingen, Germany
| | - Franz Pfeiffer
- Chair of Biomedical Physics, Department of Physics (E17), Munich, Bavaria, Germany
| | - Mike Notohamiprodjo
- Institute for Clinical Radiology, University Hospitals Munich, Munich, Germany
- Department of Radiology, University Hospital Tuebingen, Tuebingen, Germany
- * E-mail:
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23
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Yaroshenko A, Hellbach K, Bech M, Grandl S, Reiser MF, Pfeiffer F, Meinel FG. Grating-based X-ray dark-field imaging: a new paradigm in radiography. CURRENT RADIOLOGY REPORTS 2014. [DOI: 10.1007/s40134-014-0057-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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25
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Yaroshenko A, Bech M, Potdevin G, Malecki A, Biernath T, Wolf J, Tapfer A, Schüttler M, Meiser J, Kunka D, Amberger M, Mohr J, Pfeiffer F. Non-binary phase gratings for x-ray imaging with a compact Talbot interferometer. OPTICS EXPRESS 2014; 22:547-556. [PMID: 24515015 DOI: 10.1364/oe.22.000547] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
X-ray imaging using a Talbot-Lau interferometer, consisting of three binary gratings, is a well-established approach to acquire x-ray phase-contrast and dark-field images with a polychromatic source. However, challenges in the production of high aspect ratio gratings limit the construction of a compact setup for high x-ray energies. In this study we consider the use of phase gratings with triangular-shaped structures in an x-ray interferometer and show that such gratings can yield high visibilities for significantly shorter propagation distances than conventional gratings with binary structures. The findings are supported by simulation and experimental results for both cases of a monochromatic and a polychromatic source.
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