Implementation of a double-grating interferometer for phase-contrast computed tomography in a conventional system nanotom® m

Khimchenko, Anna; Schulz, Georg; Thalmann, Peter; Müller, Bert

doi:10.1063/1.5022184

Cited by 14 publications

(8 citation statements)

References 44 publications

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“…Third, PCCT could provide detailed 3D vascular morphologic information and acquire a larger field of view (FOV) than liver biopsy, but the FOV is still smaller than clinical CT. Recent research has shown that PCI could be available in commercial CT systems with a larger FOV (40). Also, the imaging of the smallest capillaries with sizes below 4 μm is still limited by the resolution.…”

Section: Discussionmentioning

confidence: 99%

Vascular branching geometry relating to portal hypertension: a study of liver microvasculature in cirrhotic rats by X-ray phase-contrast computed tomography

Sun

Zhao

et al. 2020

Quant Imaging Med Surg

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Background: Portal hypertension is one of the major complications of cirrhosis. The changes in hepatic microvasculature are considered as critical pathophysiological characteristics of portal hypertension. X-ray phase-contrast computed tomography (PCCT) is a new imaging technique that can detect liver vessels at a micrometric level without contrast agents.Methods: In this study, male Sprague-Dawley rats with liver cirrhosis induced by carbon tetrachloride (CCl 4 ) or bile duct ligation (BDL) were investigated with PCCT. The portal pressures of rats were recorded before euthanasia. The branch angle and Murray's deviation (MD) were measured based on the branching geometry of the three-dimensional (3D) microvasculature of liver cirrhosis in rats. Statistical analyses were performed to determine the correlation between branching geometry and portal pressure in liver fibrosis. Results:The results demonstrated that the branch angle and MD significantly increased in the CCl 4 model and BDL model compared with their corresponding normal group or sham group. The portal pressure was significantly correlated with the branching morphologic features (all R≥0.761 and P<0.01). Conclusions:The branch angle and MD could accurately distinguish portal pressure in cirrhotic rats, suggesting that branching geometric characteristics of the microvasculature may be a promising marker in the prognosis of portal hypertension in liver cirrhosis.

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Section: Discussionmentioning

confidence: 99%

Vascular branching geometry relating to portal hypertension: a study of liver microvasculature in cirrhotic rats by X-ray phase-contrast computed tomography

Sun

Zhao

et al. 2020

Quant Imaging Med Surg

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“…A multi-modal comparison of different imaging methods for the characterization of cartilage degeneration revealed additional quantitative information on morphology and ultra-structure by GBPC-CT compared to MRI [156]. Khimchenko et al presented electron density GBPC-CT images of cartilage and bone using an adapted commercial micro-CT system [114]. Perfusion of ischemic kidneys was analyzed with X-ray phase contrast imaging in [157].…”

Section: Applications Of Quantitative Gbpc-ctmentioning

confidence: 99%

“…This so-called source grating is an absorption grating which provides sufficient partial coherence for the method to work with extended X-ray sources like clinical X-ray tubes [ 27 ]. As an alternative to the source grating, one can also utilize micro focus X-ray source with small focal spot sizes [ 113 , 114 ] or a structured anode [ 115 , 116 ].…”

Section: Grating Interferometrymentioning

confidence: 99%

Quantitative X-ray phase contrast computed tomography with grating interferometry

Birnbacher

Braig

Pfeiffer

et al. 2021

Eur J Nucl Med Mol Imaging

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The ability of biomedical imaging data to be of quantitative nature is getting increasingly important with the ongoing developments in data science. In contrast to conventional attenuation-based X-ray imaging, grating-based phase contrast computed tomography (GBPC-CT) is a phase contrast micro-CT imaging technique that can provide high soft tissue contrast at high spatial resolution. While there is a variety of different phase contrast imaging techniques, GBPC-CT can be applied with laboratory X-ray sources and enables quantitative determination of electron density and effective atomic number. In this review article, we present quantitative GBPC-CT with the focus on biomedical applications.

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“…However, commercial systems present many obstacles to such modifications, particularly due to their compact nature with respect to custom systems. In this work, we discuss the design of the XDGI setup in a commercial µCT system and demonstrate its operation [2].…”

mentioning

confidence: 99%

“…Visibility map of the XDGI setup (a) and cross-sections of a human knee joint obtained with a commercial laboratory µCT-system equipped with the described XDGI, for phase contrast (b). Simultaneously acquired absorption contrast (c) and optimized, dedicated absorption contrast measurements (d) in the same system show reduced contrast in cartilage (white arrow in b) [2].…”

mentioning

confidence: 99%

Double Grating Interferometry in a Commercial Micro Computed Tomography System for Biomedical Imaging

et al. 2018

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X-ray grating interferometry is a phase-contrast imaging technique that provides high contrast, local electron densities, and can be translated to laboratory and medical settings. This phase contrast modality is particularly suited for the visualization of physically soft tissues and specimens that contain both soft and hard tissue components with micro computed tomography (µCT) [1]. The integration of an X-ray double grating interferometer (XDGI) into a commercially available µCT system could provide access to this technique to a greater audience. However, commercial systems present many obstacles to such modifications, particularly due to their compact nature with respect to custom systems. In this work, we discuss the design of the XDGI setup in a commercial µCT system and demonstrate its operation [2].An X-ray double grating interferometer was incorporated into a nanotomÒ m commercial laboratory µCT machine. This system does not need a source grating thanks to its microfocus tube with a range of focal spot sizes between 0.9 and 2.3 µm, as measured from radiographs of a Siemens star pattern. The system allows for a maximum source-detector distance of nearly 60 cm, limiting the ability optimize angular sensitivity by going to higher Talbot orders. The interferometer was designed for operation in a symmetric setup that uses this full distance, with source-G1 and G1-G2 distances both set to 29.4 cm. The interferometer consists of a G1 with 7 µm period and gold lines 5.8 µm high, designed to achieve a p phase shift for operation at 30 keV and a first fractional Talbot distance at 29.4 cm in the specified geometry. The absorption grating G2 has 7 µm period and gold lines 70 µm high.A part of a human knee joint was selected for the phase-contrast µCT, because it contains both hard and soft tissues. For this reason, the knee of an 87-year-old female was fixed in 10 % formalin and a cylinder 5.4 mm in diameter containing bone and cartilage was extracted from the femoral-tibial joint.Measurements of visibility and counts were made over a range of acceleration voltages for each focal spot size. The angular sensitivity [3] was optimized for a spot size of 2.0 µm and an acceleration voltage of 42 kVp. Figure 1a shows the visibility map for our setup, which achieved a mean visibility of 25 % over a 3 cm ´ 6 cm region.Phase-and absorption-contrast µCT measurements of the knee joint specimen were performed. Figure 1 shows a cross section in phase-contrast (b), simultaneously acquired absorption-contrast (c), and optimized absorption-contrast data from the nanotom® m (d). The phase measurement shows sufficient contrast to resolve the cartilage, unlike both absorption measurements. The contrast-to-noise ratio (CNR) of cartilage to formalin was measured as 1.094 ± 0.152 for phase channel, 0.073 ± 0.007 for the absorption channel, and 0.287 ± 0.003 for the optimized conventional absorption measurement.A limitation of the current setup is the low count rate due to high X-ray absorption from an Al film in

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Implementation of a double-grating interferometer for phase-contrast computed tomography in a conventional system nanotom® m

Cited by 14 publications

References 44 publications

Vascular branching geometry relating to portal hypertension: a study of liver microvasculature in cirrhotic rats by X-ray phase-contrast computed tomography

Vascular branching geometry relating to portal hypertension: a study of liver microvasculature in cirrhotic rats by X-ray phase-contrast computed tomography

Quantitative X-ray phase contrast computed tomography with grating interferometry

Double Grating Interferometry in a Commercial Micro Computed Tomography System for Biomedical Imaging

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