title: Ex Vivo Perfusion-Simulation Measurements of Microbubbles as a Scattering Contrast Agent for Grating-Based X-Ray Dark-Field Imaging.
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.
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany.
authors.forename: Astrid
authors.initials: A
authors.lastname: Velroyen
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany; Medical Radiation Physics, Lund University, Lund, Sweden.
authors.forename: Martin
authors.initials: M
authors.lastname: Bech
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany.
authors.forename: Arne
authors.initials: A
authors.lastname: Tapfer
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany.
authors.forename: Andre
authors.initials: A
authors.lastname: Yaroshenko
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany.
authors.forename: Mark
authors.initials: M
authors.lastname: Müller
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Paprottka
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Ingrisch
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
authors.forename: Clemens C
authors.initials: CC
authors.lastname: Cyran
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
authors.forename: Sigrid D
authors.initials: SD
authors.lastname: Auweter
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
authors.forename: Konstantin
authors.initials: K
authors.lastname: Nikolaou
authors.affiliation: Institute for Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Munich, Germany.
authors.forename: Maximilian F
authors.initials: MF
authors.lastname: Reiser
authors.affiliation: Lehrstuhl für Biomedizinische Physik, Physik-Department & Institut für Medizintechnik, Technische Universität München, Garching, Germany.
authors.forename: Franz
authors.initials: F
authors.lastname: Pfeiffer
mesh_terms: D000792:Angiography / Q000295:instrumentation / Q000379:methods*; D000818:Animals; D003287:Contrast Media / Q000737:chemistry; D005290:Ferric Compounds / Q000737:chemistry; D007479:Iopamidol / Q000737:chemistry; D008027:Light; D051379:Mice; D045423:Microbubbles / Q000662:veterinary*; D057054:Molecular Imaging / Q000295:instrumentation / Q000379:methods*; D010477:Perfusion; D011142:Polyvinyl Alcohol / Q000737:chemistry; D053838:Scattering, Small Angle; D014057:Tomography, X-Ray Computed / Q000295:instrumentation / Q000379:methods*
chemical_list: D003287:Contrast Media; D005290:Ferric Compounds; C000499:ferric oxide; D011142:Polyvinyl Alcohol; D007479:Iopamidol