title: Experimental studies with a 9F forward-looking intracardiac imaging and ablation catheter.
abstract: OBJECTIVE
  The purpose of this study was to develop a high-resolution, near-field-optimized 14-MHz, 24-element broad-bandwidth forward-looking array for integration on a steerable 9F electrophysiology (EP) catheter.
  
  
  METHODS
  Several generations of prototype imaging catheters with bidirectional steering, termed microlinear (ML), were built and tested as integrated catheter designs with EP sensing electrodes near the tip. The wide-bandwidth ultrasound array was mounted on the very tip, equipped with an aperture of only 1.2 by 1.58 mm. The array pulse echo performance was fully simulated, and its construction offered shielding from ablation noise. Both ex vivo and in vivo imaging with a porcine animal model were performed.
  
  
  RESULTS
  The array pulse echo performance was concordant with Krimholtz-Leedom-Matthaei model simulation. Three generations of prototype devices were tested in the right atrium and ventricle in 4 acute pig studies for the following characteristics: (1) image quality, (2) anatomic identification, (3) visualization of other catheter devices, and (4) for a mechanism for stabilization when imaging ablation. The ML catheter is capable of both low-artifact ablation imaging on a standard clinical imaging system and high-frame rate myocardial wall strain rate imaging for detecting changes in cardiac mechanics associated with ablation.
  
  
  CONCLUSIONS
  The imaging resolution performance of this very small array device, together with its penetration beyond 2 cm, is excellent considering its very small array aperture. The forward-looking intracardiac catheter has been adapted to work easily on an existing commercial imaging platform with very minor software modifications.
authors.affiliation: University of California, Davis, California USA.
authors.forename: Douglas N
authors.initials: DN
authors.lastname: Stephens
authors.forename: Matthew
authors.initials: M
authors.lastname: O'Donnell
authors.forename: Kai
authors.initials: K
authors.lastname: Thomenius
authors.forename: Aaron
authors.initials: A
authors.lastname: Dentinger
authors.forename: Douglas
authors.initials: D
authors.lastname: Wildes
authors.forename: Peter
authors.initials: P
authors.lastname: Chen
authors.forename: K Kirk
authors.initials: KK
authors.lastname: Shung
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cannata
authors.forename: Pierre
authors.initials: P
authors.lastname: Khuri-Yakub
authors.forename: Omer
authors.initials: O
authors.lastname: Oralkan
authors.forename: Aman
authors.initials: A
authors.lastname: Mahajan
authors.forename: Kalyanam
authors.initials: K
authors.lastname: Shivkumar
authors.forename: David J
authors.initials: DJ
authors.lastname: Sahn
mesh_terms: D000818:Animals; D017115:Catheter Ablation / Q000295:instrumentation* / Q000379:methods; D004452:Echocardiography / Q000295:instrumentation* / Q000379:methods; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006325:Heart Atria / Q000000981:diagnostic imaging* / Q000601:surgery*; D006352:Heart Ventricles / Q000000981:diagnostic imaging* / Q000601:surgery*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013552:Swine; D014159:Transducers