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De Marco F, Andrejewski J, Urban T, Willer K, Gromann L, Koehler T, Maack HI, Herzen J, Pfeiffer F. X-Ray Dark-Field Signal Reduction Due to Hardening of the Visibility Spectrum. IEEE TRANSACTIONS ON MEDICAL IMAGING 2024; 43:1422-1433. [PMID: 38032773 DOI: 10.1109/tmi.2023.3337994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
X-ray dark-field imaging enables a spatially-resolved visualization of ultra-small-angle X-ray scattering. Using phantom measurements, we demonstrate that a material's effective dark-field signal may be reduced by modification of the visibility spectrum by other dark-field-active objects in the beam. This is the dark-field equivalent of conventional beam-hardening, and is distinct from related, known effects, where the dark-field signal is modified by attenuation or phase shifts. We present a theoretical model for this group of effects and verify it by comparison to the measurements. These findings have significant implications for the interpretation of dark-field signal strength in polychromatic measurements.
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Grating-based spectral X-ray dark-field imaging for correlation with structural size measures. Sci Rep 2020; 10:13195. [PMID: 32764614 PMCID: PMC7411057 DOI: 10.1038/s41598-020-70011-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 07/09/2020] [Indexed: 02/01/2023] Open
Abstract
X-ray dark-field (XDF) imaging accesses information on the small-angle scattering properties of the sample. With grating interferometry, the measured scattering signal is related to the sample's autocorrelation function, which was previously demonstrated for simple samples, such as mono-dispersed microspheres for which the autocorrelation function is mathematically given. However, in potential clinical applications of XDF imaging, complex microstructures, such as lung parenchyma are under investigation. Their bahaviour in XDF imaging is not yet known and no mathematical description of the autocorrelation function is derived so far. In this work we demonstrate the previously established correlation of the XDF data of complex sample structures with their autocorrelation function to be impractical. Furthermore, we propose an applicable correlation between XDF and the sample's structural parameter on the basis of mean chord length, a medically-approved measure for alveolar structure, known to be affected by structural lung diseases. Our findings reveal a correlation between energy-dependent XDF imaging and the sample's mean chord length. By that, a connection between a medical measure for alveoli and XDF is achieved, which is particularly important regarding potential future XDF lung imaging applications for the assessment of alveoli size in diagnostic lung imaging.
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Mechlem K, Sellerer T, Viermetz M, Herzen J, Pfeiffer F. Spectral Differential Phase Contrast X-Ray Radiography. IEEE TRANSACTIONS ON MEDICAL IMAGING 2020; 39:578-587. [PMID: 31380752 DOI: 10.1109/tmi.2019.2932450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We investigate the combination of two emerging X-ray imaging technologies, namely spectral imaging and differential phase contrast imaging. By acquiring spatially and temporally registered images with several different X-ray spectra, spectral imaging can exploit differences in the energy-dependent attenuation to generate material selective images. Differential phase contrast imaging uses an entirely different contrast generation mechanism: The phase shift that an X-ray wave exhibits when traversing an object. As both methods can determine the (projected) electron density, we propose a novel material decomposition algorithm that uses the spectral and the phase contrast information simultaneously. Numerical experiments show that the combination of these two imaging techniques benefits from the strengths of the individual methods while the weaknesses are mitigated: Quantitatively accurate basis material images are obtained and the noise level is strongly reduced, compared to conventional spectral X-ray imaging.
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Seki Y, Shinohara T, Parker JD, Ueno W, Samoto T, Yashiro W, Momose A, Otake Y, Kiyanagi Y. Efficient phase imaging using wavelength-resolved neutron Talbot-Lau interferometry with TOF method. ACTA ACUST UNITED AC 2018. [DOI: 10.1209/0295-5075/123/12002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Hetterich H, Webber N, Willner M, Herzen J, Birnbacher L, Auweter S, Schüller U, Bamberg F, Notohamiprodjo S, Bartsch H, Wolf J, Marschner M, Pfeiffer F, Reiser M, Saam T. Dark-field imaging in coronary atherosclerosis. Eur J Radiol 2017; 94:38-45. [PMID: 28941758 DOI: 10.1016/j.ejrad.2017.07.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 07/21/2017] [Indexed: 02/01/2023]
Abstract
OBJECTIVES Dark-field imaging based on small angle X-ray scattering has been shown to be highly sensitive for microcalcifications, e.g. in breast tissue. We hypothesized (i) that high signal areas in dark-field imaging of atherosclerotic plaque are associated with microcalcifications and (ii) that dark-field imaging is more sensitive for microcalcifications than attenuation-based imaging. METHODS Fifteen coronary artery specimens were examined at an experimental set-up consisting of X-ray tube (40kV), grating-interferometer and detector. Tomographic dark-field-, attenuation-, and phase-contrast data were simultaneously acquired. Histopathology served as standard of reference. To explore the potential of dark field imaging in a full-body CT system, simulations were carried out with spherical calcifications of different sizes to simulate small and intermediate microcalcifications. RESULTS Microcalcifications were present in 10/10 (100%) cross-sections with high dark-field signal and without evidence of calcifications in attenuation- or phase contrast. In positive controls with high signal areas in all three modalities, 10/10 (100%) cross-sections showed macrocalcifications. In negative controls without high signal areas, no calcifications were detected. Simulations showed that the microcalcifications generate substantially higher dark-field than attenuation signal. CONCLUSIONS Dark-field imaging is highly sensitive for microcalcifications in coronary atherosclerotic plaque and might provide complementary information in the assessment of plaque instability.
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Affiliation(s)
- Holger Hetterich
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany.
| | - Nicole Webber
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Marian Willner
- Physics Department & Institute for Medical Engineering, Technical University Munich, Garching, Germany
| | - Julia Herzen
- Physics Department & Institute for Medical Engineering, Technical University Munich, Garching, Germany
| | - Lorenz Birnbacher
- Physics Department & Institute for Medical Engineering, Technical University Munich, Garching, Germany
| | - Sigrid Auweter
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Ulrich Schüller
- Center for Neuropathology, Ludwig-Maximilians-University Hospital, Munich, Germany; Institute for Neuropathology, University Medical Center Hamburg, Germany; Department for Pediatric Hematology and Oncology, University Medical Center Hamburg, Germany
| | - Fabian Bamberg
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Susan Notohamiprodjo
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Harald Bartsch
- Institute of Pathology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Johannes Wolf
- Physics Department & Institute for Medical Engineering, Technical University Munich, Garching, Germany
| | - Mathias Marschner
- Physics Department & Institute for Medical Engineering, Technical University Munich, Garching, Germany
| | - Franz Pfeiffer
- Physics Department & Institute for Medical Engineering, Technical University Munich, Garching, Germany
| | - Maximilian Reiser
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
| | - Tobias Saam
- Institute of Clinical Radiology, Ludwig-Maximilians-University Hospital, Munich, Germany
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Sharma Y, Schaff F, Wieczorek M, Pfeiffer F, Lasser T. Design of Acquisition Schemes and Setup Geometry for Anisotropic X-ray Dark-Field Tomography (AXDT). Sci Rep 2017; 7:3195. [PMID: 28600544 PMCID: PMC5466688 DOI: 10.1038/s41598-017-03329-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2017] [Accepted: 04/26/2017] [Indexed: 11/23/2022] Open
Abstract
Anisotropic X-ray Dark-field Tomography (AXDT) is a new imaging technique for reconstructing the three-dimensional scattering profile within a sample using the dark-field signal measured in an X-ray grating interferometry setup. As in any tomographic measurement, the acquisition geometry plays a key role in the accurate reconstruction of the scattering information. More- over, the anisotropic nature of the dark-field signal poses additional challenges for designing the acquisition protocols. In this work, we present an efficient approach to measure scattering orientations spread over the unit sphere and prove its efficacy using the knowledge from conventional tomography. In addition, we conclude (using analytical and experimental results) that placing the gratings such that the grating bars make an angle of 45 degrees with respect to the vertical direction is the optimal setup configuration for AXDT.
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Affiliation(s)
- Y Sharma
- Chair of Biomedical Physics, Department of Physics and School of BioEngineering, Technical University of Munich, 85748, Garching, Germany.
- Computer Aided Medical Procedures, Technical University of Munich, 85748, Garching, Germany.
| | - F Schaff
- Chair of Biomedical Physics, Department of Physics and School of BioEngineering, Technical University of Munich, 85748, Garching, Germany
| | - M Wieczorek
- Computer Aided Medical Procedures, Technical University of Munich, 85748, Garching, Germany
| | - F Pfeiffer
- Chair of Biomedical Physics, Department of Physics and School of BioEngineering, 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
| | - T Lasser
- Computer Aided Medical Procedures, Technical University of Munich, 85748, Garching, Germany
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