Quantitative evaluation of atrial radio frequency ablation using intracardiac shear‐wave elastography. Issue 11 (20th October 2014)

• Record Type: Journal Article
• Authors: Kwiecinski, Wojciech; Provost, Jean; Dubois, Rémi; Sacher, Frédéric; Haïssaguerre, Michel; Legros, Mathieu; Nguyen‐Dinh, An; Dufait, Rémi; Tanter, Mickaël; Pernot, Mathieu
• Is Part Of: Medical physics. Volume 41:Issue 11(2014)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2014-10-20
• Subjects: biological tissues -- biomechanics -- biomedical transducers -- biomedical ultrasonics -- cardiology -- catheters -- radiation therapy -- radiofrequency heating -- shear modulus -- surgery -- ultrasonic transducer arrays; Ultrasonographic imaging -- Therapeutic applications -- Mechanical and electrical properties of tissues and organs; Diagnosis using ultrasonic, sonic or infrasonic waves -- Surgical instruments, devices or methods, e.g. tourniquets -- Catheters; Hollow probes -- Radiation therapy -- Processes or apparatus for generating mechanical vibrations of infrasonic, sonic or ultrasonic frequency -- Biological material, e.g. blood, urine; Haemocytometers -- Heating by electric, magnetic, or electromagnetic fields; shear‐wave elastography -- ultrasound -- thermal ablation monitoring -- intracardiac echocardiography -- atrial fibrillation; Tissue ablation -- Ultrasonography -- Cardiac dynamics -- Elastic moduli -- Tissues -- Heart -- Thermal imaging -- Transducers -- Pathology; Medical physics -- Periodicals; Medical physics; Geneeskunde; Natuurkunde; Toepassingen; Biophysics; Periodicals; Periodicals; Electronic journals; 610.153
• DOI: 10.1118/1.4896820
• Languages: English
• ISSNs: 0094-2405

Abstract

Abstract : Purpose: Radio frequency catheter ablation (RFCA) is a well‐established clinical procedure for the treatment of atrial fibrillation (AF) but suffers from a low single‐procedure success rate. Recurrence of AF is most likely attributable to discontinuous or nontransmural ablation lesions. Yet, despite this urgent clinical need, there is no clinically available imaging modality that can reliably map the lesion transmural extent in real time. In this study, the authors demonstrated the feasibility of shear‐wave elastography (SWE) to map quantitatively the stiffness of RFCA‐induced thermal lesions in cardiac tissues in vitro and in vivo using an intracardiac transducer array. Methods: SWE was first validated in ex vivo porcine ventricular samples ( N = 5). Both B‐mode imaging and SWE were performed on normal cardiac tissue before and after RFCA. Areas of the lesions were determined by tissue color change with gross pathology and compared against the SWE stiffness maps. SWE was then performed in vivo in three sheep ( N = 3). First, the stiffness of normal atrial tissues was assessed quantitatively as well as its variation during the cardiac cycle. SWE was then performed in atrial tissue after RFCA. Results: A large increase in stiffness was observed in ablated ex vivo regions (average shear modulus across samples in normal tissue: 22 ± 5 kPa, average shear‐wave speed ( ct ): 4.5 ± 0.4 m s −1 and in determined ablated zones: 99 ± 17 kPa, average ct : 9.0 ± 0.5 m s −1 for a mean shear modulus increase ratio of 4.5 ± 0.9). In vivo, a threefold increase of the shear modulus was measured in the ablated regions, and the lesion extension was clearly visible on the stiffness maps. Conclusions: By its quantitative and real‐time capabilities, Intracardiac SWE is a promising intraoperative imaging technique for the evaluation of thermal ablation during RFCA.