title: A Novel Inherently Radiopaque Bead for Transarterial Embolization to Treat Liver Cancer - A Pre-clinical Study.
abstract: OBJECTIVE
  Embolotherapy using microshperes is currently performed with soluble contrast to aid in visualization. However, administered payload visibility dimishes soon after delivery due to soluble contrast washout, leaving the radiolucent bead's location unknown. The objective of our study was to characterize inherently radiopaque beads (RO Beads) in terms of physicomechanical properties, deliverability and imaging visibility in a rabbit VX2 liver tumor model.
  
  
  METHODS
  RO Beads, which are based on LC Bead® platform, were compared to LC Bead. Bead size (light microscopy), equilibrium water content (EWC), density, X-ray attenuation and iodine distribution (micro-CT), suspension (settling times), deliverability and in vitro penetration were investigated. Fifteen rabbits were embolized with either LC Bead or RO Beads + soluble contrast (iodixanol-320), or RO Beads+dextrose. Appearance was evaluated with fluoroscopy, X-ray single shot, cone-beam CT (CBCT).
  
  
  RESULTS
  Both bead types had a similar size distribution. RO Beads had lower EWC (60-72%) and higher density (1.21-1.36 g/cc) with a homogeneous iodine distribution within the bead's interior. RO Beads suspension time was shorter than LC Bead, with durable suspension (>5 min) in 100% iodixanol. RO Beads ≤300 µm were deliverable through a 2.3-Fr microcatheter. Both bead types showed similar penetration. Soluble contrast could identify target and non-target embolization on fluoroscopy during administration. However, the imaging appearance vanished quickly for LC Bead as contrast washed-out. RO Beads+contrast significantly increased visibility on X-ray single shot compared to LC Bead+contrast in target and non-target arteries (P=0.0043). Similarly, RO beads demonstrated better visibility on CBCT in target arteries (P=0.0238) with a trend in non-target arteries (P=0.0519). RO Beads+dextrose were not sufficiently visible to monitor embolization using fluoroscopy.
  
  
  CONCLUSIONS
  RO Beads provide better conspicuity to determine target and non-target embolization compared to LC Bead which may improve intra-procedural monitoring and post-procedural evaluation of transarterial embolization.
authors.affiliation: 1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Johns Hopkins Hospital, Baltimore, MD, USA ; 2. Department of Diagnostic Radiology and Imaging Science, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Rafael
authors.initials: R
authors.lastname: Duran
authors.affiliation: 3. Department of Diagnostic Imaging and Radiology, Children's National Medical Center, Washington, DC, USA.
authors.forename: Karun
authors.initials: K
authors.lastname: Sharma
authors.affiliation: 4. Biocompatibles Inc, Oxford, CT, USA.
authors.forename: Matthew R
authors.initials: MR
authors.lastname: Dreher
authors.affiliation: 5. Biocompatibles UK Ltd, a BTG International group company, Farnham, Surrey, United Kingdom.
authors.forename: Koorosh
authors.initials: K
authors.lastname: Ashrafi
authors.affiliation: 1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Johns Hopkins Hospital, Baltimore, MD, USA.
authors.forename: Sahar
authors.initials: S
authors.lastname: Mirpour
authors.affiliation: 6. U/S Imaging and Interventions (UII), Philips Research North America, Briarcliff Manor, NY, USA.
authors.forename: MingDe
authors.initials: M
authors.lastname: Lin
authors.affiliation: 1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Johns Hopkins Hospital, Baltimore, MD, USA ; 2. Department of Diagnostic Radiology and Imaging Science, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Ruediger E
authors.initials: RE
authors.lastname: Schernthaner
authors.affiliation: 1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Johns Hopkins Hospital, Baltimore, MD, USA ; 2. Department of Diagnostic Radiology and Imaging Science, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Todd R
authors.initials: TR
authors.lastname: Schlachter
authors.affiliation: 1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Johns Hopkins Hospital, Baltimore, MD, USA.
authors.forename: Vania
authors.initials: V
authors.lastname: Tacher
authors.affiliation: 5. Biocompatibles UK Ltd, a BTG International group company, Farnham, Surrey, United Kingdom.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Lewis
authors.affiliation: 5. Biocompatibles UK Ltd, a BTG International group company, Farnham, Surrey, United Kingdom.
authors.forename: Sean
authors.initials: S
authors.lastname: Willis
authors.affiliation: 7. iXR, Philips Healthcare, Best, The Netherlands.
authors.forename: Mark
authors.initials: M
authors.lastname: den Hartog
authors.affiliation: 7. iXR, Philips Healthcare, Best, The Netherlands.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Radaelli
authors.affiliation: 8. Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Ayele H
authors.initials: AH
authors.lastname: Negussie
authors.affiliation: 8. Center for Interventional Oncology, Radiology and Imaging Sciences, Clinical Center, National Institutes of Health, Bethesda, MD, USA.
authors.forename: Bradford J
authors.initials: BJ
authors.lastname: Wood
authors.affiliation: 1. Russell H. Morgan Department of Radiology and Radiological Science, Division of Vascular and Interventional Radiology, Johns Hopkins Hospital, Baltimore, MD, USA ; 2. Department of Diagnostic Radiology and Imaging Science, Yale University School of Medicine, New Haven, CT, USA.
authors.forename: Jean-François H
authors.initials: JF
authors.lastname: Geschwind
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D004621:Embolization, Therapeutic / Q000379:methods*; D005471:Fluoroscopy; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000628:therapy*; D008863:Microspheres; D011817:Rabbits; D011859:Radiography / Q000379:methods*; D013194:Staining and Labeling / Q000379:methods*
keywords: Embolization; Hepatocellular carcinoma; TACE; VX2; radiopaque beads