First in vivo use of a capacitive micromachined ultrasound transducer array-based imaging and ablation catheter.
OBJECTIVE
The primary objective was to test in vivo for the first time the general operation of a new multifunctional intracardiac echocardiography (ICE) catheter constructed with a microlinear capacitive micromachined ultrasound transducer (ML-CMUT) imaging array. Secondarily, we examined the compatibility of this catheter with electroanatomic mapping (EAM) guidance and also as a radiofrequency ablation (RFA) catheter. Preliminary thermal strain imaging (TSI)-derived temperature data were obtained from within the endocardium simultaneously during RFA to show the feasibility of direct ablation guidance procedures.


METHODS
The new 9F forward-looking ICE catheter was constructed with 3 complementary technologies: a CMUT imaging array with a custom electronic array buffer, catheter surface electrodes for EAM guidance, and a special ablation tip, that permits simultaneous TSI and RFA. In vivo imaging studies of 5 anesthetized porcine models with 5 CMUT catheters were performed.


RESULTS
The ML-CMUT ICE catheter provided high-resolution real-time wideband 2-dimensional (2D) images at greater than 8 MHz and is capable of both RFA and EAM guidance. Although the 24-element array aperture dimension is only 1.5 mm, the imaging depth of penetration is greater than 30 mm. The specially designed ultrasound-compatible metalized plastic tip allowed simultaneous imaging during ablation and direct acquisition of TSI data for tissue ablation temperatures. Postprocessing analysis showed a first-order correlation between TSI and temperature, permitting early development temperature-time relationships at specific myocardial ablation sites.


CONCLUSIONS
Multifunctional forward-looking ML-CMUT ICE catheters, with simultaneous intracardiac guidance, ultrasound imaging, and RFA, may offer a new means to improve interventional ablation procedures.
University of California, Davis, California, USA.
Douglas N
DN
Stephens
Uyen T
UT
Truong
Amin
A
Nikoozadeh
Omer
O
Oralkan
Chi Hyung
CH
Seo
Jonathan
J
Cannata
Aaron
A
Dentinger
Kai
K
Thomenius
Alan
A
de la Rama
Tho
T
Nguyen
Feng
F
Lin
Pierre
P
Khuri-Yakub
Aman
A
Mahajan
Kalyanam
K
Shivkumar
Matt
M
O'Donnell
David J
DJ
Sahn
D000818:Animals; D006328:Cardiac Catheterization / Q000295:instrumentation*; D017115:Catheter Ablation / Q000295:instrumentation*; D004452:Echocardiography / Q000295:instrumentation*; D022062:Electrophysiologic Techniques, Cardiac / Q000295:instrumentation; D004867:Equipment Design; D005471:Fluoroscopy; D013552:Swine; D014159:Transducers; D018084:Ultrasonography, Interventional / Q000295:instrumentation*