title: Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model.
abstract: OBJECTIVE
  Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design.
  
  
  METHODS
  A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components.
  
  
  RESULTS
  Hypodense artifacts volumes (mm³) were 1,029 ± 147, 535 ± 53, 371 ± 16, and 366 ± 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 ± 141, 2,387 ± 103, 2,003 ± 102, and 3,033 ± 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types).
  
  
  CONCLUSIONS
  Both valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed.
authors.affiliation: Department of Cardiothoracic Surgery, Onze Lieve Vrouwe Gasthuis, Amsterdam, The Netherlands. psymersky@gmail.com
authors.forename: Petr
authors.initials: P
authors.lastname: Symersky
authors.forename: Ricardo P J
authors.initials: RP
authors.lastname: Budde
authors.forename: Paul
authors.initials: P
authors.lastname: Westers
authors.forename: Bas A J M
authors.initials: BA
authors.lastname: de Mol
authors.forename: Mathias
authors.initials: M
authors.lastname: Prokop
mesh_terms: D000465:Algorithms; D016477:Artifacts; D002309:Cardiology / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D006350:Heart Valve Prosthesis; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D015233:Models, Statistical; D008962:Models, Theoretical; D009038:Motion; D061330:Multidetector Computed Tomography / Q000379:methods*; D011474:Prosthesis Design; D011673:Pulsatile Flow