title: The progression of thrombus in an ex-vivo shunt model evaluated by intravascular ultrasound radiofrequency analysis.
abstract: We tested the ability of ultrasound radiofrequency (RF) signal analysis to characterize thrombus accumulation in a Dacron graft incorporated into the exteriorized arteriovenous shunt in 3 baboons with constant blood flow for 60 min. Thrombus formation was quantified by sequential measurements of 111Indium-labeled platelet deposition. RF signals were acquired every 15 min at 2 sites in the graft, using a 2.9 Fr intravascular ultrasound catheter-based transducer (30 MHz) and digitized at 250 MHz in 8-bit resolution. Regions of interest were placed within a 0.5-mm perimeter adjacent to the graft wall. Integrated backscatter increased significantly (p < 0.001) with increasing platelet deposition. However, mean-to-standard deviation ratio of the RF envelope showed no significant change and the distribution pattern of the RF probability function remained constant and consistent with a Rayleigh scattering process. These results provide a basis for using RF analysis to monitor the time-course of thrombus formation.
authors.affiliation: Division of Cardiovascular Medicine, Stanford University School of Medicine, CA, USA. nkomiyam@aa.mbn.or.jp
authors.forename: N
authors.initials: N
authors.lastname: Komiyama
authors.forename: N A
authors.initials: NA
authors.lastname: Chronos
authors.forename: N G
authors.initials: NG
authors.lastname: Uren
authors.forename: M P
authors.initials: MP
authors.lastname: Moore
authors.forename: A B
authors.initials: AB
authors.lastname: Kelly
authors.forename: L A
authors.initials: LA
authors.lastname: Harker
authors.forename: S R
authors.initials: SR
authors.lastname: Hanson
authors.forename: J A
authors.initials: JA
authors.lastname: Metz
authors.forename: P G
authors.initials: PG
authors.lastname: Yock
authors.forename: P J
authors.initials: PJ
authors.lastname: Fitzgerald
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001166:Arteriovenous Shunt, Surgical; D001807:Blood Vessel Prosthesis; D004195:Disease Models, Animal; D018450:Disease Progression; D005263:Femoral Artery; D005268:Femoral Vein; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging; D010215:Papio; D011093:Polyethylene Terephthalates; D013927:Thrombosis / Q000000981:diagnostic imaging*; D013997:Time Factors; D018084:Ultrasonography, Interventional / Q000295:instrumentation / Q000379:methods* / Q000706:statistics & numerical data
chemical_list: D011093:Polyethylene Terephthalates