title: Quantification of Multiple Mitral Regurgitant Jets: An In Vitro Validation Study Comparing Two- and Three-Dimensional Proximal Isovelocity Surface Area Methods.
abstract: BACKGROUND
  The accuracy of the proximal isovelocity surface area (PISA) method for the quantification of mitral regurgitation (MR), in the case of multiple jets, is unknown. The aim of this study was to evaluate different two-dimensional (2D) and three-dimensional (3D) PISA methods using 3D color Doppler data sets.
  
  
  METHODS
  Several regurgitant volumes (Rvols) were simulated using a pulsatile pump connected to a phantom equipped with single and double regurgitant orifices of different sizes and interspaces. A flowmeter served as the reference method. Transthoracic (TTE) and transoesophageal echocardiography (TEE) were used to acquire the 3D data sets. Offline, Rvols were calculated by 2D PISA methods based on hemispheric and hemicylindric assumptions and by 3D integrated PISA.
  
  
  RESULTS
  A fusion of the PISA was observed in the setting of narrow-spaced regurgitant orifices; compared with flowmeter, Rvol was underestimated using the single hemispheric PISA model (TTE: Bland-Altman bias ± limit of agreement, -17.5 ± 8.9 mL; TEE: -15.9 ± 7.3 mL) and overestimated using the double hemispheric PISA model (TTE: +7.1 ± 14.6 mL; TEE: +10.4 ± 11.9 mL). The combined approach (hemisphere for single orifice, hemicylinder with two bases for nonfused PISAs, and hemicylinder with one base for fused PISAs) was more precise (TTE: -3.4 ± 6.3 mL; TEE: -1.9 ± 5.6 mL). Three-dimensional integrated PISA was the most accurate method to quantify Rvol (TTE: -2.1 ± 6.5 mL; TEE -3.2 ± 4.8 mL).
  
  
  CONCLUSIONS
  In the setting of double MR orifices, the 2D combined approach and integrated 3D PISA appear to be superior as compared with the conventional hemispheric method, thus providing tools for the challenging quantification of MR with multiple jets.
authors.affiliation: Department of Cardiology, University Hospital, Bern, Switzerland.
authors.forename: Fabian
authors.initials: F
authors.lastname: Zürcher
authors.affiliation: Department of Cardiology, Hôpital Fribourgeois, Fribourg, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Brugger
authors.affiliation: ARTORG Center, University of Bern, Bern, Switzerland.
authors.forename: Silje Ekroll
authors.initials: SE
authors.lastname: Jahren
authors.affiliation: Department of Cardiology, University Hospital, Bern, Switzerland.
authors.forename: Stefano Fausto
authors.initials: SF
authors.lastname: de Marchi
authors.affiliation: Department of Cardiology, University Hospital, Bern, Switzerland. Electronic address: Christian.seiler@insel.ch.
authors.forename: Christian
authors.initials: C
authors.lastname: Seiler
mesh_terms: D001783:Blood Flow Velocity; D018618:Echocardiography, Doppler, Color / Q000295:instrumentation / Q000379:methods*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008944:Mitral Valve Insufficiency / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D019047:Phantoms, Imaging; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: 2D color Doppler echocardiography; 3D color Doppler echocardiography; Mitral regurgitation quantification; Multiple regurgitant orifices; Proximal isovelocity surface area