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Developing a Microbubble-Based Contrast Agent for Synchrotron In-Line Phase Contrast Imaging.
- Source :
-
IEEE transactions on bio-medical engineering [IEEE Trans Biomed Eng] 2021 May; Vol. 68 (5), pp. 1527-1535. Date of Electronic Publication: 2021 Apr 21. - Publication Year :
- 2021
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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.<br />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 × 10 <superscript>7</superscript> , 5 × 10 <superscript>6</superscript> and 5 × 10 <superscript>5</superscript> 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.<br />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.<br />Conclusion: These data indicate that lipid-MBs larger than 4 μm are candidates for PCI, and 5 × 10 <superscript>6</superscript> MBs/ml may be the lowest concentration suitable for generating visible phase contrast in vivo.<br />Significance: Identifying a suitable MB for PCI may facilitate future clinical translation.
- Subjects :
- Canada
Synchrotrons
Ultrasonography
X-Ray Microtomography
Contrast Media
Microbubbles
Subjects
Details
- Language :
- English
- ISSN :
- 1558-2531
- Volume :
- 68
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- IEEE transactions on bio-medical engineering
- Publication Type :
- Academic Journal
- Accession number :
- 33232220
- Full Text :
- https://doi.org/10.1109/TBME.2020.3040079