title: In vitro in-stent restenoses evaluated by 3D ultrasound.
abstract: The purpose of this study was to quantify in-stent restenoses with 3D B mode and power Doppler ultrasound (U.S.) imaging. In-stent restenoses were mimicked with vascular phantoms in which a nonferromagnetic prototype stent (Boston Scientific) and a ferromagnetic clinical stainless steel stent (Palmaz P295) were embedded. Each phantom had an 80% in-stent stenosis and a 75% stenosis located outside the stent. These phantoms were compared to a reference phantom reproducing both stenoses without stent. Data sets of 2D cross-sectional U.S. images were acquired in freehand scanning using a magnetic sensor attached to the U.S. probe and in mechanical linear scanning with the probe attached to a step motor device. Each 2D image was automatically segmented before 3D reconstruction of the vessel. Results indicate that the reference phantom (without stent) was accurately assessed with errors below 1.8% for the 75% stenosis and 3.2% for the 80% stenosis in both B mode and power Doppler for the two scanning methods. The 80% in-stent stenoses in Boston Scientific and Palmaz stents were, respectively, evaluated at 73.8 (+/-3.2)% and 75.8 (+/- 3)% in B mode and at 82 (+/- 2.5)% and 86.2 (+/- 6.4)% in power Doppler when freehand scans were used. For comparison, when linear scans were selected, in-stent stenoses in the Boston Scientific or Palmaz stent were, respectively, evaluated at 77.4 (+/- 2.0)% and 73.8 (+/- 2.5)% in B mode and at 87.0 (+/- 1.3)% and 85.6 (+/- 5.8)% in power Doppler. To conclude, 3D freehand U.S. is a valuable method to quantify in-stent restenoses, particularly in B mode. It is thus hoped that, in the clinical setting, noninvasive 3D U.S. may provide sufficient precision to grade in-stent restenoses.
authors.affiliation: Laboratory of Biorheology and Medical Ultrasonics, University of Montreal Hospital Research Center (CRCHUM), 2099 Alexandre de Sève (room Y-1619), Montréal, Québec H2L 2W5, Canada.
authors.forename: Myriam
authors.initials: M
authors.lastname: Lécart
authors.forename: Marie-Hélène Roy
authors.initials: MH
authors.lastname: Cardinal
authors.forename: Zhao
authors.initials: Z
authors.lastname: Qin
authors.forename: Gilles
authors.initials: G
authors.lastname: Soulez
authors.forename: Guy
authors.initials: G
authors.lastname: Cloutier
mesh_terms: D016477:Artifacts; D005290:Ferric Compounds; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging* / Q000209:etiology* / Q000473:pathology; D021621:Imaging, Three-Dimensional / Q000295:instrumentation*; D019047:Phantoms, Imaging; D015607:Stents / Q000009:adverse effects*; D014465:Ultrasonics; D014463:Ultrasonography
chemical_list: D005290:Ferric Compounds; C001215:ferrite