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Peri-Ablation Monitoring of RFA Lesion Stiffness. Introduction: Elastography imaging can provide ... more Peri-Ablation Monitoring of RFA Lesion Stiffness. Introduction: Elastography 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 Results: In 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, ß0.5-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. Conclusions: Ultrasound-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. acoustic radiation force impulse imaging, elastography, intraprocedure radiofrequency ablation lesion assessment , shear wave elasticity imaging
Journal of cardiovascular electrophysiology, Jan 12, 2015
Elastography imaging can provide radiofrequency ablation (RFA) lesion assessment due to tissue st... more Elastography 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 two 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. In 6 canine subjects, SWEI measurements and 2-D ARFI images were acquired at six ventricular endocardial RFA sites before, during, and for 30 minutes post ablation. An immediate increase in tissue stiffness was detected during RFA, and the area of the post-ablation region of stiffness increase (RoSI) as well as the relative stiffness at the RoSI center were stable approximately 2 minutes after ablation. Of note is the observation that relative stiffnes...
Background: Visual confirmation of radiofrequency ablation (RFA) lesions during clinical cardiac ... more 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-inhuman " 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 TM ultrasound scanner and 8/10Fr AcuNav TM ultrasound catheter, or (2) a CARTO 3 TM integrated Siemens SC2000 TM and 10Fr SoundStar TM 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. (J Cardiovasc Electrophysiol, Vol. pp. 1-9) acoustic radiation force impulse imaging, atrial fibrillation, atrial flutter, electroanatomical mapping, intracardiac echocardiography, lesion assessment, transcatheter radiofrequency ablation
We have previously shown that intracardiac acoustic radiation force impulse (ARFI) imaging visual... more We have previously shown that intracardiac acoustic radiation force impulse (ARFI) imaging visualizes tissue stiffness changes caused by radiofrequency ablation (RFA). The objectives of this in vivo study were to (1) quantify measured ARFI-induced displacements in RFA lesion and unablated myocardium and (2) calculate the lesion contrast (C) and contrast-to-noise ratio (CNR) in two-dimensional ARFI and conventional intracardiac echo images. In eight canine subjects, an ARFI imaging-electroanatomical mapping system was used to map right atrial ablation lesion sites and guide the acquisition of ARFI images at these sites before and after ablation. Readers of the ARFI images identified lesion sites with high sensitivity (90.2%) and specificity (94.3%) and the average measured ARFI-induced displacements were higher at unablated sites (11.23 ± 1.71 µm) than at ablated sites (6.06 ± 0.94 µm). The average lesion C (0.29 ± 0.33) and CNR (1.83 ± 1.75) were significantly higher for ARFI images than for spatially registered conventional B-mode images (C = −0.03 ± 0.28, CNR = 0.74 ± 0.68).
Journal of Cardiovascular Electrophysiology, Nov 2012
Heart Rhythm, Nov 2012
Background: Arrhythmia recurrence after cardiac radiofrequency ablation (RFA) for atrial fibrilla... more Background: Arrhythmia recurrence after cardiac radiofrequency ablation (RFA) for atrial fibrillation has been linked to conduction through discontinuous lesion lines. Intraprocedural visualization and corrective ablation of lesion line discontinuities could decrease postprocedure atrial fibrillation recurrence. Intracardiac acoustic radiation force impulse (ARFI) imaging is a new imaging technique that visualizes RFA lesions by mapping the relative elasticity contrast between compliant-unablated and stiff RFA-treated myocardium.
Objective: To determine whether intraprocedure ARFI images can identify RFA-treated myocardium in vivo.
Methods: In 8 canines, an electroanatomical mapping–guided intracardiac echo catheter was used to acquire 2-dimensional ARFI images along right atrial ablation lines before and after RFA. ARFI images were acquired during diastole with the myocardium positioned at the ARFI focus (1.5 cm) and parallel to the intracardiac echo transducer for maximal and uniform energy delivery to the tissue. Three reviewers categorized each ARFI image as depicting no lesion, noncontiguous lesion, or contiguous lesion. For comparison, 3 separate reviewers confirmed RFA lesion presence and contiguity on the basis of functional conduction block at the imaging plane location on electroanatomical mapping activation maps.
Results: Ten percent of ARFI images were discarded because of motion artifacts. Reviewers of the ARFI images detected RFA-treated sites with high sensitivity (95.7%) and specificity (91.5%). Reviewer identification of contiguous lesions had 75.3% specificity and 47.1% sensitivity.
Conclusions: Intracardiac ARFI imaging was successful in identifying endocardial RFA treatment when specific imaging conditions were maintained. Further advances in ARFI imaging technology would facilitate a wider range of imaging opportunities for clinical lesion evaluation.
Journal of …, May 2010
Introduction: Lesion placement and transmurality are critical factors in the success of cardiac t... more Introduction: Lesion placement and transmurality are critical factors in the success of cardiac transcatheter radiofrequency ablation (RFA) treatments for supraventricular arrhythmias. This study investigated the capabilities of catheter transducer based acoustic radiation force impulse (ARFI) ultrasound imaging for quantifying ablation lesion dimensions.
Methods and Results: RFA lesions were created in vitro in porcine ventricular myocardium and imaged with an intracardiac ultrasound catheter transducer capable of acquiring spatially registered B-mode and ARFI images. The myocardium was sliced along the imaging plane and photographed. The maximum ARFI-induced displacement images of the lesion were normalized and spatially registered with the photograph by matching the surfaces of the tissue in the B-mode and photographic images. The lesion dimensions determined by a manual segmentation of the photographed lesion based on the visible discoloration of the tissue were compared to automatic segmentations of the ARFI image using 2 different calculated thresholds. ARFI imaging accurately localized and sized the lesions within the myocardium. Differences in the maximum lateral and axial dimensions were statistically below 2 mm and 1 mm, respectively, for the 2 thresholding methods, with mean percent overlap of 68.7 ± 5.21% and 66.3 ± 8.4% for the 2 thresholds used.
Conclusion: ARFI imaging is capable of visualizing myocardial RFA lesion dimensions to within 2 mm in vitro. Visualizing lesions during transcatheter cardiac ablation procedures could improve the success of the treatment by imaging lesion line discontinuity and potentially reducing the required number of ablation lesions and procedure time.
(J Cardiovasc Electrophysiol, Vol. 21, pp. 557-563, May 2010)
Journal Covers by Stephanie Eyerly
JCE Cover Figure, May 2010
Heart Rhythm Cover Nov. 2012
Posters by Stephanie Eyerly
Conference Abstracts and Proceedings by Stephanie Eyerly
2013 IEEE International Ultrasonics Symposium (IUS), 2013
ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generati... more ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generating a contiguous series of discrete radiofrequency ablation (RFA) lesions in the myocardium to destroy or isolate arrhythmogenic conduction pathways. The size of each lesion is controlled by the duration and power of the delivered RF energy, and by the temperature of the tissue at the surface, but feedback on the extent and transmurality of the generated lesion are unavailable with current technology. Intracardiac Echocardiography (ICE) may provide a solution through Acoustic Radiation Force Impulse (ARFI) imaging or Shear Wave Imaging (SWI), which each generate images of local mechanical compliance from very small ultrasonically-induced waves. This work compares ARFI and SWI in an ex vivo experiment for lesion boundary assessment and lesion gap resolution.
IEEE Ultrasonic Symposium 2009 Proceedings, Sep 2009
Cardiovascular disease remains the most likely cause of death in developed countries, accounting ... more Cardiovascular disease remains the most likely cause of death in developed countries, accounting for approximately 870,000 deaths in the United States alone in 2004. Virtually every form of cardiovascular disease involves modifications in tissue stiffness. Acoustic radiation force impulse (ARFI) imaging shows great promise in the regional characterization of tissue stiffness in a variety of clinical applications. Cardiovascular tissues present unique challenges to ARFI imaging because of their dynamic changes in stiffness, high-amplitude physiological motion, and elevated stiffness levels compared to other tissues. We have implemented ARFI and shear wave elasticity imaging (SWEI) on a commercially available scanner. These imaging methods were employed on: canine and ovine heart models. Myocardial stiffness measurements were obtained throughout the cardiac cycle and with various manipulations of tissue status (ie: radiofrequency ablation, myocardial ischemia, and heart rate) under epicardial and transthoracic imaging conditions. ARFI imaging resolution was similar to corresponding B-mode images. The ARFI-induced displacement and recovery curves exhibited cyclic variations that reflected the expected changes in stiffness through the cardiac cycle. Shear wave velocimetry was successfully implemented. Also, ARFI imaging was capable of visualizing changes in myocardial stiffness due to the presence of a radiofrequency ablation-created lesion, varying heart rates, and acute myocardial ischemia. A parametric pressure-volume and ARFI imaging analysis also suggests that ARFI imaging provides unique and previously unavailable information into myocardial performance and function.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generati... more ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generating a contiguous series of discrete radiofrequency ablation (RFA) lesions in the myocardium to destroy or isolate arrhythmogenic conduction pathways. The size of each lesion is controlled by the duration and power of the delivered RF energy, and by the temperature of the tissue at the surface, but feedback on the extent and transmurality of the generated lesion are unavailable with current technology. Intracardiac Echocardiography (ICE) may provide a solution through Acoustic Radiation Force Impulse (ARFI) imaging or Shear Wave Imaging (SWI), which each generate images of local mechanical compliance from very small ultrasonically-induced waves. This work compares ARFI and SWI in an ex vivo experiment for lesion boundary assessment and lesion gap resolution.
2014 IEEE International Ultrasonics Symposium, 2014
Peri-Ablation Monitoring of RFA Lesion Stiffness. Introduction: Elastography imaging can provide ... more Peri-Ablation Monitoring of RFA Lesion Stiffness. Introduction: Elastography 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 Results: In 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, ß0.5-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. Conclusions: Ultrasound-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. acoustic radiation force impulse imaging, elastography, intraprocedure radiofrequency ablation lesion assessment , shear wave elasticity imaging
Journal of cardiovascular electrophysiology, Jan 12, 2015
Elastography imaging can provide radiofrequency ablation (RFA) lesion assessment due to tissue st... more Elastography 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 two 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. In 6 canine subjects, SWEI measurements and 2-D ARFI images were acquired at six ventricular endocardial RFA sites before, during, and for 30 minutes post ablation. An immediate increase in tissue stiffness was detected during RFA, and the area of the post-ablation region of stiffness increase (RoSI) as well as the relative stiffness at the RoSI center were stable approximately 2 minutes after ablation. Of note is the observation that relative stiffnes...
Background: Visual confirmation of radiofrequency ablation (RFA) lesions during clinical cardiac ... more 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-inhuman " 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 TM ultrasound scanner and 8/10Fr AcuNav TM ultrasound catheter, or (2) a CARTO 3 TM integrated Siemens SC2000 TM and 10Fr SoundStar TM 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. (J Cardiovasc Electrophysiol, Vol. pp. 1-9) acoustic radiation force impulse imaging, atrial fibrillation, atrial flutter, electroanatomical mapping, intracardiac echocardiography, lesion assessment, transcatheter radiofrequency ablation
We have previously shown that intracardiac acoustic radiation force impulse (ARFI) imaging visual... more We have previously shown that intracardiac acoustic radiation force impulse (ARFI) imaging visualizes tissue stiffness changes caused by radiofrequency ablation (RFA). The objectives of this in vivo study were to (1) quantify measured ARFI-induced displacements in RFA lesion and unablated myocardium and (2) calculate the lesion contrast (C) and contrast-to-noise ratio (CNR) in two-dimensional ARFI and conventional intracardiac echo images. In eight canine subjects, an ARFI imaging-electroanatomical mapping system was used to map right atrial ablation lesion sites and guide the acquisition of ARFI images at these sites before and after ablation. Readers of the ARFI images identified lesion sites with high sensitivity (90.2%) and specificity (94.3%) and the average measured ARFI-induced displacements were higher at unablated sites (11.23 ± 1.71 µm) than at ablated sites (6.06 ± 0.94 µm). The average lesion C (0.29 ± 0.33) and CNR (1.83 ± 1.75) were significantly higher for ARFI images than for spatially registered conventional B-mode images (C = −0.03 ± 0.28, CNR = 0.74 ± 0.68).
Journal of Cardiovascular Electrophysiology, Nov 2012
Heart Rhythm, Nov 2012
Background: Arrhythmia recurrence after cardiac radiofrequency ablation (RFA) for atrial fibrilla... more Background: Arrhythmia recurrence after cardiac radiofrequency ablation (RFA) for atrial fibrillation has been linked to conduction through discontinuous lesion lines. Intraprocedural visualization and corrective ablation of lesion line discontinuities could decrease postprocedure atrial fibrillation recurrence. Intracardiac acoustic radiation force impulse (ARFI) imaging is a new imaging technique that visualizes RFA lesions by mapping the relative elasticity contrast between compliant-unablated and stiff RFA-treated myocardium.
Objective: To determine whether intraprocedure ARFI images can identify RFA-treated myocardium in vivo.
Methods: In 8 canines, an electroanatomical mapping–guided intracardiac echo catheter was used to acquire 2-dimensional ARFI images along right atrial ablation lines before and after RFA. ARFI images were acquired during diastole with the myocardium positioned at the ARFI focus (1.5 cm) and parallel to the intracardiac echo transducer for maximal and uniform energy delivery to the tissue. Three reviewers categorized each ARFI image as depicting no lesion, noncontiguous lesion, or contiguous lesion. For comparison, 3 separate reviewers confirmed RFA lesion presence and contiguity on the basis of functional conduction block at the imaging plane location on electroanatomical mapping activation maps.
Results: Ten percent of ARFI images were discarded because of motion artifacts. Reviewers of the ARFI images detected RFA-treated sites with high sensitivity (95.7%) and specificity (91.5%). Reviewer identification of contiguous lesions had 75.3% specificity and 47.1% sensitivity.
Conclusions: Intracardiac ARFI imaging was successful in identifying endocardial RFA treatment when specific imaging conditions were maintained. Further advances in ARFI imaging technology would facilitate a wider range of imaging opportunities for clinical lesion evaluation.
Journal of …, May 2010
Introduction: Lesion placement and transmurality are critical factors in the success of cardiac t... more Introduction: Lesion placement and transmurality are critical factors in the success of cardiac transcatheter radiofrequency ablation (RFA) treatments for supraventricular arrhythmias. This study investigated the capabilities of catheter transducer based acoustic radiation force impulse (ARFI) ultrasound imaging for quantifying ablation lesion dimensions.
Methods and Results: RFA lesions were created in vitro in porcine ventricular myocardium and imaged with an intracardiac ultrasound catheter transducer capable of acquiring spatially registered B-mode and ARFI images. The myocardium was sliced along the imaging plane and photographed. The maximum ARFI-induced displacement images of the lesion were normalized and spatially registered with the photograph by matching the surfaces of the tissue in the B-mode and photographic images. The lesion dimensions determined by a manual segmentation of the photographed lesion based on the visible discoloration of the tissue were compared to automatic segmentations of the ARFI image using 2 different calculated thresholds. ARFI imaging accurately localized and sized the lesions within the myocardium. Differences in the maximum lateral and axial dimensions were statistically below 2 mm and 1 mm, respectively, for the 2 thresholding methods, with mean percent overlap of 68.7 ± 5.21% and 66.3 ± 8.4% for the 2 thresholds used.
Conclusion: ARFI imaging is capable of visualizing myocardial RFA lesion dimensions to within 2 mm in vitro. Visualizing lesions during transcatheter cardiac ablation procedures could improve the success of the treatment by imaging lesion line discontinuity and potentially reducing the required number of ablation lesions and procedure time.
(J Cardiovasc Electrophysiol, Vol. 21, pp. 557-563, May 2010)
JCE Cover Figure, May 2010
Heart Rhythm Cover Nov. 2012
2013 IEEE International Ultrasonics Symposium (IUS), 2013
ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generati... more ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generating a contiguous series of discrete radiofrequency ablation (RFA) lesions in the myocardium to destroy or isolate arrhythmogenic conduction pathways. The size of each lesion is controlled by the duration and power of the delivered RF energy, and by the temperature of the tissue at the surface, but feedback on the extent and transmurality of the generated lesion are unavailable with current technology. Intracardiac Echocardiography (ICE) may provide a solution through Acoustic Radiation Force Impulse (ARFI) imaging or Shear Wave Imaging (SWI), which each generate images of local mechanical compliance from very small ultrasonically-induced waves. This work compares ARFI and SWI in an ex vivo experiment for lesion boundary assessment and lesion gap resolution.
IEEE Ultrasonic Symposium 2009 Proceedings, Sep 2009
Cardiovascular disease remains the most likely cause of death in developed countries, accounting ... more Cardiovascular disease remains the most likely cause of death in developed countries, accounting for approximately 870,000 deaths in the United States alone in 2004. Virtually every form of cardiovascular disease involves modifications in tissue stiffness. Acoustic radiation force impulse (ARFI) imaging shows great promise in the regional characterization of tissue stiffness in a variety of clinical applications. Cardiovascular tissues present unique challenges to ARFI imaging because of their dynamic changes in stiffness, high-amplitude physiological motion, and elevated stiffness levels compared to other tissues. We have implemented ARFI and shear wave elasticity imaging (SWEI) on a commercially available scanner. These imaging methods were employed on: canine and ovine heart models. Myocardial stiffness measurements were obtained throughout the cardiac cycle and with various manipulations of tissue status (ie: radiofrequency ablation, myocardial ischemia, and heart rate) under epicardial and transthoracic imaging conditions. ARFI imaging resolution was similar to corresponding B-mode images. The ARFI-induced displacement and recovery curves exhibited cyclic variations that reflected the expected changes in stiffness through the cardiac cycle. Shear wave velocimetry was successfully implemented. Also, ARFI imaging was capable of visualizing changes in myocardial stiffness due to the presence of a radiofrequency ablation-created lesion, varying heart rates, and acute myocardial ischemia. A parametric pressure-volume and ARFI imaging analysis also suggests that ARFI imaging provides unique and previously unavailable information into myocardial performance and function.
2013 IEEE International Ultrasonics Symposium (IUS), 2013
ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generati... more ABSTRACT Radiofrequency ablation (RFA) is commonly used to treat cardiac arrhythmias, by generating a contiguous series of discrete radiofrequency ablation (RFA) lesions in the myocardium to destroy or isolate arrhythmogenic conduction pathways. The size of each lesion is controlled by the duration and power of the delivered RF energy, and by the temperature of the tissue at the surface, but feedback on the extent and transmurality of the generated lesion are unavailable with current technology. Intracardiac Echocardiography (ICE) may provide a solution through Acoustic Radiation Force Impulse (ARFI) imaging or Shear Wave Imaging (SWI), which each generate images of local mechanical compliance from very small ultrasonically-induced waves. This work compares ARFI and SWI in an ex vivo experiment for lesion boundary assessment and lesion gap resolution.
2014 IEEE International Ultrasonics Symposium, 2014
2013 IEEE International Ultrasonics Symposium (IUS), 2013
2014 Ieee International Ultrasonics Symposium, Sep 1, 2014