Challenges and implementation of radiation-force imaging with an intracardiac ultrasound transducer

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2007-05, Vol.54 (5), p.996-1009
• Main Authors: Hsu, S.J., Fahey, B.J., Dumont, D.M., Wolf, P.D., Trahey, G.E.
• Format: Article
• Language: English
• Subjects: Ablation; Acoustic imaging; Acoustic signal processing; Acoustic transducers; Acoustics; Algorithms; Animals; Biological and medical sciences; Breast cancer; Cardiac Catheterization - instrumentation; Catheter Ablation - instrumentation; Catheter Ablation - methods; Echocardiography - instrumentation; Echocardiography - methods; Equipment Design; Equipment Failure Analysis; Exact sciences and technology; Feasibility Studies; Fundamental areas of phenomenology (including applications); High-resolution imaging; Ice; Image contrast; Image Enhancement - instrumentation; Image Enhancement - methods; Imaging; Investigative techniques, diagnostic techniques (general aspects); Lesions; Medical sciences; Miscellaneous. Technology; Monitoring; Monitors; Optical imaging; Physics; Probes; Reproducibility of Results; Sensitivity and Specificity; Sheep; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery, Computer-Assisted - instrumentation; Surgery, Computer-Assisted - methods; Transducers; Transduction; acoustical devices for the generation and reproduction of sound; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonic transducers; Ultrasound
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2007.345

Intracardiac echocardiography (ICE) has been demonstrated to be an effective imaging modality for the guidance of several cardiac procedures, including radiofrequency ablation (RFA). However, assessing lesion size during the ablation with conventional ultrasound has been limited, as the associated changes within the B-mode images often are subtle. Acoustic radiation force impulse (ARFI) imaging is a promising modality to monitor RFAs as it is capable of visualizing variations in local stiffnesses within the myocardium. We demonstrate ARPI imaging with an intracardiac probe that creates higher quality images of the developing lesion. We evaluated the performance of an ICE probe with ARFI imaging in monitoring RFAs. The intracardiac probe was used to create high contrast, high resolution ARFI images of a tissue-mimicking phantom containing stiffer spherical inclusions. The probe also was used to examine an excised segment of an ovine right ventricle with a RFA-created surface lesion. Although the lesion was not visible in conventional B-mode images, the ARFI images were able to show the boundaries between the lesion and the surrounding tissue. ARFI imaging with an intracardiac probe then was used to monitor cardiac ablations in vivo. RFAs were performed within the right atrium of an ovine heart, and B-mode and ARFI imaging with the intracardiac probe was used to monitor the developing lesions. Although there was little indication of a developing lesion within the B-mode images, the corresponding ARFI images displayed regions around the ablation site that displaced less