Contrast in Intracardiac Acoustic Radiation Force Impulse Images of Radiofrequency Ablation Lesions

Eyerly, Stephanie A.; Bahnson, Tristram D.; Koontz, Jason I.; Bradway, David; Dumont, Douglas M.; Trahey, Gregg E.; Wolf, Patrick D.

doi:10.1177/0161734613519602

Cited by 10 publications

(9 citation statements)

References 55 publications

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“…Also, recent studies have concluded that current methods of MRI assessment of atrial RFA lesions show limited resolution for characterizing small gaps in an ablation line . Intracardiac ARFI imaging provides higher spatial resolution (sub‐millimeter) than current MRI methods …”

Section: Discussionsupporting

confidence: 68%

“…RFA induced tissue heating causes irreversible thermocoagulation of intracellular and contractile proteins, which in turn reduces tissue viscoelasticity . Although RFA does not produce long lasting detectable tissue changes in standard 2‐D ultrasound images, it has been previously shown that ARFI imaging identifies discrete stiff regions that coincide with pathological RFA lesions both in vitro , and when imaging during diastole in vivo using animal models , . Further, in several of these in vivo studies, ARFI imaging was implemented using conventional intracardiac echocardiography (ICE) imaging catheters and clinically available cardiac ablation mapping systems, and regions with “gaps” in the ablation line as identified with ARFI imaging were correlated with intact conduction …”

Section: Introductionmentioning

confidence: 99%

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Feasibility of Near Real‐Time Lesion Assessment During Radiofrequency Catheter Ablation in Humans Using Acoustic Radiation Force Impulse Imaging

Bahnson

Eyerly

Hollender

et al. 2014

Cardiovasc electrophysiol

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Background Visual confirmation of radiofrequency ablation (RFA) lesions during clinical cardiac ablation procedures could improve procedure efficacy, safety, and efficiency. It was previously shown that acoustic radiation force impulse (ARFI) imaging can identify RFA lesions in vitro and in vivo in an animal model. This is the “first-in-human” feasibility demonstration of intracardiac ARFI imaging of RFA lesions in patients undergoing catheter ablation for atrial flutter (AFL) or atrial fibrillation (AF). Methods and Results Patients scheduled for right atrial (RA) ablation for AFL or left atrial (LA) ablation for drug refractory AF were eligible for imaging. Diastole-gated intracardiac ARFI images were acquired using one of two equipment configurations: (1) a Siemens ACUSON S2000™ ultrasound scanner and 8/10Fr AcuNav™ ultrasound catheter, or (2) a CARTO 3™ integrated Siemens SC2000™ and 10Fr SoundStar™ ultrasound catheter. A total of 11 patients (AFL = 3; AF = 8) were imaged. ARFI images were acquired of ablation target regions, including the RA cavotricuspid isthmus (CTI), and the LA roof, pulmonary vein ostia, posterior wall, posterior mitral valve annulus, and the ridge between the pulmonary vein and LA appendage. ARFI images revealed increased relative myocardial stiffness at ablation catheter contact sites after RFA and at anatomical mapping-tagged RFA treatment sites. Conclusions ARFI images from a pilot group of patients undergoing catheter ablation for AFL and AF demonstrate the ability of this technique to identify intra-procedure RFA lesion formation. The results encourage further refinement of ARFI imaging clinical tools and continued investigation in larger clinical trials.

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Section: Discussionsupporting

confidence: 68%

Section: Introductionmentioning

confidence: 99%

Feasibility of Near Real‐Time Lesion Assessment During Radiofrequency Catheter Ablation in Humans Using Acoustic Radiation Force Impulse Imaging

Bahnson

Eyerly

Hollender

et al. 2014

Cardiovasc electrophysiol

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“…The measured ARFI‐induced displacement magnitude is inversely proportional to tissue stiffness and presents a representation of the relative stiffness . We have previously shown in vitro that ARFI imaging can visualize RFA lesions, and that in vivo intracardiac echocardiography (ICE) based diastolic ARFI imaging can provide high‐contrast visualization of stiff atrial lesions consistent with electrical block at the imaging site . Initial results from a clinical feasibility study demonstrated that ARFI imaging could identify stiffness changes consistent with RF ablation in human patients …”

Section: Introductionmentioning

confidence: 99%

The Evolution of Tissue Stiffness at Radiofrequency Ablation Sites During Lesion Formation and in the Peri‐Ablation Period

Eyerly

Vejdani‐Jahromi

Dumont

et al. 2015

Cardiovasc electrophysiol

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Peri‐Ablation Monitoring of RFA Lesion StiffnessIntroductionElastography imaging can provide radiofrequency ablation (RFA) lesion assessment due to tissue stiffening at the ablation site. An important aspect of assessment is the spatial and temporal stability of the region of stiffness increase in the peri‐ablation period. The aim of this study was to use 2 ultrasound‐based elastography techniques, shear wave elasticity imaging (SWEI) and acoustic radiation force impulse (ARFI) imaging, to monitor the evolution of tissue stiffness at ablation sites in the 30 minutes following lesion creation.Methods and ResultsIn 6 canine subjects, SWEI measurements and 2‐D ARFI images were acquired at 6 ventricular endocardial RFA sites before, during, and for 30 minutes postablation. An immediate increase in tissue stiffness was detected during RFA, and the area of the postablation region of stiffness increase (RoSI) as well as the relative stiffness at the RoSI center was stable approximately 2 minutes after ablation. Of note is the observation that relative stiffness in the region adjacent to the RoSI increased slightly during the first 15 minutes, consistent with local fluid displacement or edema. The magnitude of this increase, ∼0.5‐fold from baseline, was significantly less than the magnitude of the stiffness increase directly inside the RoSI, which was greater than 3‐fold from baseline.ConclusionsUltrasound‐based SWEI and ARFI imaging detected an immediate increase in tissue stiffness during RFA, and the stability and magnitude of the stiffness change suggest that consistent elasticity‐based lesion assessment is possible 2 minutes after and for at least 30 minutes following ablation.

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“…However, in these previous studies, atrial function in ablated patients was measured after several months follow-up whereas in this study strains are measured several minutes to hours before, during and after ablation. Eyerly et al investigated the change of acoustic radiation force induced displacement of myocardial tissue with ICE in canines during an RF ablation [24, 50]. They reported that displacements in ablated sites were inferior to displacement in unablated sites.…”

Section: Discussionmentioning

confidence: 99%

Intracardiac myocardial elastography in canines and humans in vivo

Grondin

Wan

Gambhir

et al. 2015

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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Intracardiac echocardiography (ICE) is a useful imaging modality which is used during radiofrequency (RF) ablation procedures to help identify anatomical structures. Utilizing ICE in adjunct with myocardial elastography (ME) can provide additional information on the mechanical properties of cardiac tissue and provide information on mechanical changes due to ablation. The objective of this study was to demonstrate that ICE can be used at high frame rate using a diverging beam transmit sequence to image myocardial strain and differentiate myocardial tissue properties before, during and after ablation for a clinical ablation procedure. In this feasibility study, three normal canines and eight patients with atrial fibrillation (AF) were studied in vivo. A 5.8-MHz ICE transducer was used to image the heart with a diverging beam transmit method achieving 1200 frames per second (fps). Cumulative axial displacement estimation was performed using 1-D cross-correlation with a window size of 2.7mm and 95% overlap. Axial cumulative strains were estimated in left atrium (LA) and right atrium (RA) using a least-squares estimator with a kernel of 2mm on the axial displacements. In the canine case, radial thickening was detected in the lateral wall and in the interatrial septum during LA emptying. For AF patients, mean absolute strain in the ablated region was lower (6.7±3.1%) than before the ablation (17.4±9.3%) in LA at end LA emptying. In the cavotricuspid isthmus (CTI) region, mean absolute strain magnitude at end RA emptying was found to be higher during ablation (43.0±18.1%) compared to after ablation (33.7±15.8%). Myocardial strains in the LA of an AF patient were approximately 2.6 times lower in the ablated region than before ablation. This initial feasibility may suggest ME as a new imaging modality to be used in adjunct with ICE in RF ablation guidance and lesion monitoring.

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Contrast in Intracardiac Acoustic Radiation Force Impulse Images of Radiofrequency Ablation Lesions

Cited by 10 publications

References 55 publications

Feasibility of Near Real‐Time Lesion Assessment During Radiofrequency Catheter Ablation in Humans Using Acoustic Radiation Force Impulse Imaging

Feasibility of Near Real‐Time Lesion Assessment During Radiofrequency Catheter Ablation in Humans Using Acoustic Radiation Force Impulse Imaging

The Evolution of Tissue Stiffness at Radiofrequency Ablation Sites During Lesion Formation and in the Peri‐Ablation Period

Intracardiac myocardial elastography in canines and humans in vivo

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