Advanced Real-time MR-Guided Radiofrequency Ablation of Cardiac Arrhythmias
Lead Research Organisation:
King's College London
Department Name: Imaging & Biomedical Engineering
Abstract
Cardiac arrhythmias affect 2 million people a year in the UK. Radio-frequency (RF) ablation (RFA) procedures are clinically available to treat the majority of cardiac arrhythmias. Overall, ~20,000 RFA of cardiac arrhythmias are being performed every year in the UK. RFA uses catheter-based localized delivery of radio-frequency energy resulting in localized tissue heating. Sufficient temperature increase (~30-50C for ~30-60sec) is necessary to create permanent tissue destruction (necrosis). The aim of RFA procedures is to create permanent tissue destruction of critical heart tissues causing arrhythmias. This is often achieved by creating lines of permanent ablation lesions to electrically block/isolate these critical sites. Since each ablation point has a maximum size of ~6-8mm, multiple ablations are commonly performed to create ablation lines. Currently, 30-50% of RFA procedures fail due to the presence of gaps in ablation lines and the incorrect location/extent of the permanent RFA lesions. Furthermore, RFA procedures may have severe complications including cardiac perforation which can arise from steam explosion occurring when tissue temperature exceeds 100C. Finally, potential catheter drift during RFA should be prevented to avoid ablation of undesired tissues. Current real time RFA guidance systems (X-ray, electro-anatomical mapping) are unable to monitor tissue temperature and extent of permanent RFA lesions. Indirect parameters such as RF power/duration, catheter tip temperature, catheter contact force/impedance are monitored during RFA but have low predictive values of tissue temperature and permanent RFA lesion extent. Notably, the discrepancy between the catheter-tip temperature and tissue temperature can be >30C. Therefore, real time accurate monitoring of tissue temperature and prediction of permanent RFA lesion extent is very likely to improve the outcome and safety of the procedure.
Magnetic resonance (MR)-thermometry is a non-invasive MRI technique which enables real time pixel-wise assessment of temperature, deep in tissue. Permanent tissue destruction can be predicted using the concept of thermal dose (thereafter referred to as MR-dosimetry) which is based on a model of temperature elevation and time of exposure. However, current cardiac MR-thermometry/dosimetry methods that are not ideal for clinical translation (long acquisition window, low spatial resolution, sensitivity to physiological motion, and high noise level in temperature maps) and a clinically feasible method remains still to be demonstrated, as does its accuracy for prevention of ablation gaps and prediction of chronic permanent RFA lesion extent.
This research proposal aims to develop a novel clinically feasible real-time cardiac MR-thermometry/dosimetry framework which addresses the current unmet need, to evaluate its performance in a pre-clinical study, and to demonstrate its feasibility in a first-in-man clinical study.
Magnetic resonance (MR)-thermometry is a non-invasive MRI technique which enables real time pixel-wise assessment of temperature, deep in tissue. Permanent tissue destruction can be predicted using the concept of thermal dose (thereafter referred to as MR-dosimetry) which is based on a model of temperature elevation and time of exposure. However, current cardiac MR-thermometry/dosimetry methods that are not ideal for clinical translation (long acquisition window, low spatial resolution, sensitivity to physiological motion, and high noise level in temperature maps) and a clinically feasible method remains still to be demonstrated, as does its accuracy for prevention of ablation gaps and prediction of chronic permanent RFA lesion extent.
This research proposal aims to develop a novel clinically feasible real-time cardiac MR-thermometry/dosimetry framework which addresses the current unmet need, to evaluate its performance in a pre-clinical study, and to demonstrate its feasibility in a first-in-man clinical study.
Planned Impact
This research will deliver impact at multiple levels.
A) Impact on healthcare and the NHS
Cardiac arrhythmias affect 2 million people a year in the UK. Radio-frequency ablation (RFA) procedures are clinically available to treat a majority of cardiac arrhythmias such as atrial fibrillation or ventricular tachycardia (VT). Overall, ~20,000 RFA of cardiac arrhythmias are being performed every year in the UK. Currently, 30-50% of RFA procedures fail because of the presence of gaps in ablation lines and incorrect location/extent of permanent RFA lesions. Our initial clinical target will be CMR-guided VT ablation procedures. 28,000 individuals die annually of sudden cardiac death (SCD) as a consequence of VT in England and Wales. Implantable cardioverter defibrillator (ICD) therapy is a first line treatment for SCD prevention but is not curative. VT ablation is an additional treatment which reduces the morbidity/mortality in patients with ICD. Although VT ablation is a curative therapy, this procedure currently fails in 50% of cases, requires repeat procedures and is associated with complications (3% mortality). This research aim at developing a novel approach to VT ablation using real-time cardiac magnetic resonance imaging (CMR) guidance.
A method of VT ablation that has a much higher success rate would have substantial impact on healthcare and the NHS. First, it would reduce adverse events and poor quality of life related to appropriate and inappropriate ICD shocks. Second, it could also transform the current care pathway by simply alleviating the need of costly ICDs. An efficient method to VT ablation would also substantially reduce the need of repeat procedures, further contributing to healthcare cost reduction.
B) Impact on patients
In addition to potential long term healthcare benefit, short term impact on patients will be achieved by engaging patient groups in our research. Our research findings will be presented to patients through organised events but also to more specific patient groups undergoing VT ablation procedures.
C) Impact on general public
A range of public engagement activities (including organised events, use of social media, and release from the KCL press office) will be used to enhance general public awareness of our research findings but also to stimulate the curiosity and creativity of children/teenagers who will be the next generation of researchers.
D) Impact on industry
We believe industrial partnership is key in this project to ensure rapid clinical impact in this field. Our industrial partners will provide critical feedback to this project. The proposed technical innovations developed in this research will be made available to others sites to ensure maximum spread of the technique. The proposed technical developments also have potential to generate associated IP and will be first protected in consultation with the King's College IP & Licensing team.
E) Impact on UK research competitiveness
This research will also impact UK research competitiveness by maintaining an internationally leading MR-guided cardiac ablation programme at St' Thomas Hospital/KCL with a world leading expertise in CMR, cardiac electrophysiology, and CMR-guided procedures. This project has the potential to make CMR-guided VT ablation accessible throughout the UK by dissemination through academic, clinical and industrial links with other Trusts around the country that perform VT ablation procedures.
F) Impact on research communities
This research will generate knowledge in a multi-disciplinary fashion, both within the UK and internationally. This knowledge will benefit several communities including the engineering and image/signal processing communities, the CMR community, the cardiology/cardiac electrophysiology community.
G) Impact on team members
A range of activities will be conducted to ensure maximum impact on the career of the team members and to help them becoming independent researchers.
A) Impact on healthcare and the NHS
Cardiac arrhythmias affect 2 million people a year in the UK. Radio-frequency ablation (RFA) procedures are clinically available to treat a majority of cardiac arrhythmias such as atrial fibrillation or ventricular tachycardia (VT). Overall, ~20,000 RFA of cardiac arrhythmias are being performed every year in the UK. Currently, 30-50% of RFA procedures fail because of the presence of gaps in ablation lines and incorrect location/extent of permanent RFA lesions. Our initial clinical target will be CMR-guided VT ablation procedures. 28,000 individuals die annually of sudden cardiac death (SCD) as a consequence of VT in England and Wales. Implantable cardioverter defibrillator (ICD) therapy is a first line treatment for SCD prevention but is not curative. VT ablation is an additional treatment which reduces the morbidity/mortality in patients with ICD. Although VT ablation is a curative therapy, this procedure currently fails in 50% of cases, requires repeat procedures and is associated with complications (3% mortality). This research aim at developing a novel approach to VT ablation using real-time cardiac magnetic resonance imaging (CMR) guidance.
A method of VT ablation that has a much higher success rate would have substantial impact on healthcare and the NHS. First, it would reduce adverse events and poor quality of life related to appropriate and inappropriate ICD shocks. Second, it could also transform the current care pathway by simply alleviating the need of costly ICDs. An efficient method to VT ablation would also substantially reduce the need of repeat procedures, further contributing to healthcare cost reduction.
B) Impact on patients
In addition to potential long term healthcare benefit, short term impact on patients will be achieved by engaging patient groups in our research. Our research findings will be presented to patients through organised events but also to more specific patient groups undergoing VT ablation procedures.
C) Impact on general public
A range of public engagement activities (including organised events, use of social media, and release from the KCL press office) will be used to enhance general public awareness of our research findings but also to stimulate the curiosity and creativity of children/teenagers who will be the next generation of researchers.
D) Impact on industry
We believe industrial partnership is key in this project to ensure rapid clinical impact in this field. Our industrial partners will provide critical feedback to this project. The proposed technical innovations developed in this research will be made available to others sites to ensure maximum spread of the technique. The proposed technical developments also have potential to generate associated IP and will be first protected in consultation with the King's College IP & Licensing team.
E) Impact on UK research competitiveness
This research will also impact UK research competitiveness by maintaining an internationally leading MR-guided cardiac ablation programme at St' Thomas Hospital/KCL with a world leading expertise in CMR, cardiac electrophysiology, and CMR-guided procedures. This project has the potential to make CMR-guided VT ablation accessible throughout the UK by dissemination through academic, clinical and industrial links with other Trusts around the country that perform VT ablation procedures.
F) Impact on research communities
This research will generate knowledge in a multi-disciplinary fashion, both within the UK and internationally. This knowledge will benefit several communities including the engineering and image/signal processing communities, the CMR community, the cardiology/cardiac electrophysiology community.
G) Impact on team members
A range of activities will be conducted to ensure maximum impact on the career of the team members and to help them becoming independent researchers.
Publications
McElroy S
(2022)
Simultaneous multislice steady-state free precession myocardial perfusion with full left ventricular coverage and high resolution at 1.5 T.
in Magnetic resonance in medicine
McElroy S
(2022)
Simultaneous multi-slice steady-state free precession myocardial perfusion with iterative reconstruction and integrated motion compensation.
in European journal of radiology
Nazir MS
(2018)
Simultaneous multi slice (SMS) balanced steady state free precession first-pass myocardial perfusion cardiovascular magnetic resonance with iterative reconstruction at 1.5 T.
in Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
Neofytou AP
(2023)
Retrospective motion correction through multi-average k-space data elimination (REMAKE) for free-breathing cardiac cine imaging.
in Magnetic resonance in medicine
Vidya Shankar R
(2024)
Real-time automatic image-based slice tracking of gadolinium-filled balloon wedge catheter during MR-guided cardiac catheterization: A proof-of-concept study.
in Magnetic resonance in medicine
Aimo A
(2022)
Quantitative susceptibility mapping (QSM) of the cardiovascular system: challenges and perspectives.
in Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
Nazir M
(2022)
Quantitative Myocardial Perfusion With Simultaneous-Multislice Stress CMR for Detection of Significant Coronary Artery Disease
in JACC: Cardiovascular Imaging
López K
(2020)
Quantitative magnetization transfer imaging for non-contrast enhanced detection of myocardial fibrosis
in Magnetic Resonance in Medicine
McElroy S
(2021)
Quantification of balanced SSFP myocardial perfusion imaging at 1.5 T: Impact of the reference image
in Magnetic Resonance in Medicine
Velasco Forte MN
(2021)
MRI for Guided Right and Left Heart Cardiac Catheterization: A Prospective Study in Congenital Heart Disease.
in Journal of magnetic resonance imaging : JMRI
Whitaker J
(2021)
Late Gadolinium Enhancement Cardiovascular Magnetic Resonance Assessment of Substrate for Ventricular Tachycardia With Hemodynamic Compromise
in Frontiers in Cardiovascular Medicine
Veeram Reddy SR
(2020)
Invasive cardiovascular magnetic resonance (iCMR) for diagnostic right and left heart catheterization using an MR-conditional guidewire and passive visualization in congenital heart disease.
in Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
Whitaker J
(2019)
Improved co-registration of ex-vivo and in-vivo cardiovascular magnetic resonance images using heart-specific flexible 3D printed acrylic scaffold combined with non-rigid registration.
in Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance
Mooiweer R
(2023)
Feasibility of cardiac MR thermometry at 0.55 T.
in Frontiers in cardiovascular medicine
Huang L
(2020)
FASt single-breathhold 2D multislice myocardial T1 mapping (FAST1) at 1.5T for full left ventricular coverage in three breathholds.
in Journal of magnetic resonance imaging : JMRI
Huang L
(2019)
Fast myocardial T 1 mapping using shortened inversion recovery based schemes
in Journal of Magnetic Resonance Imaging
Campos FO
(2019)
Factors Promoting Conduction Slowing as Substrates for Block and Reentry in Infarcted Hearts.
in Biophysical journal
Mukherjee RK
(2019)
Evaluation of a real-time magnetic resonance imaging-guided electrophysiology system for structural and electrophysiological ventricular tachycardia substrate assessment.
in Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology
Mukherjee RK
(2018)
Epicardial electroanatomical mapping, radiofrequency ablation, and lesion imaging in the porcine left ventricle under real-time magnetic resonance imaging guidance-an in vivo feasibility study.
in Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology
Elliott M
(2022)
Effect of scar and pacing location on repolarization in a porcine myocardial infarction model
in Heart Rhythm O2
Huang L
(2021)
Editorial for "Impact of Wideband Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging on Device-Related Artifacts in Different Implantable Cardioverter-Defibrillator Types"
in Journal of Magnetic Resonance Imaging
Wang S
(2020)
Development and Testing of an Ultrasound-Compatible Cardiac Phantom for Interventional Procedure Simulation Using Direct Three-Dimensional Printing.
in 3D printing and additive manufacturing
López K
(2020)
Contrast-free high-resolution 3D magnetization transfer imaging for simultaneous myocardial scar and cardiac vein visualization.
in Magma (New York, N.Y.)
McElroy S
(2020)
Combined simultaneous multislice bSSFP and compressed sensing for first-pass myocardial perfusion at 1.5 T with high spatial resolution and coverage.
in Magnetic resonance in medicine
Neofytou AP
(2023)
Automatic image-based tracking of gadolinium-filled balloon wedge catheters for MRI-guided cardiac catheterization using deep learning.
in Frontiers in cardiovascular medicine
Description | - Improved measurement of tissue temperature during thermal ablation of cardiac arrhythmia to better monitor ablation lesions. - Improved dynamic cardiac MRI with higher spatial coverage and spatial resolution. - Improved prospective respiratory motion correction in dynamic cardiac MRI. - Improved tracking of interventional devices during interventional cardiac MRI procedures. - Demonstration of the technology during MRI-guided cardiac ablation procedures in pre-clinical studies. |
Exploitation Route | The outcome may be used for the development of an MRI-guided cardiac ablation product platform. |
Sectors | Healthcare Pharmaceuticals and Medical Biotechnology |
Description | Real-time MR-thermometry for interventional MRI at low field in moving organs |
Amount | £185,340 (GBP) |
Organisation | Innovate UK |
Sector | Public |
Country | United Kingdom |
Start | 01/2021 |
End | 12/2023 |
Description | Siemens - CMR developments |
Organisation | Siemens Healthcare |
Country | Germany |
Sector | Private |
PI Contribution | We developed several novel acquisition, reconstruction and post-processing approaches which have resulted in several joint publications and patents. |
Collaborator Contribution | Siemens has supported all our developments through their on-site clinical scientists at St Thomas Hospital. This has been instrumental in the successful development of the technology and its translation in patients. |
Impact | All outcomes (publications and patents) related to this award and listed in appropriate section have been made jointly with Siemens. |
Start Year | 2015 |
Title | A method and apparatus for controlling the generation of a magnetic resonance imaging sequence |
Description | A method using a magnetic resonance apparatus to control an imaging sequence, by generating a tracking sequence to track the position of an active MR device, obtaining signals from the device because of the tracking sequence, processing to determine the position, determining if the position satisfies a trigger condition and generating the imaging sequence if the trigger is satisfied. If not, the images aren't generated, and the method may be repeated. The imaging sequence may be started a predetermined time after the trigger is met, the time may be selected to be generated during a specific point in the subjects' motion, such as cardiac or respiratory cycles, the point may correspond to a resting state. The image sequence may be an MR thermometry sequence. The active device may be a receive coil and may be part of an invasive device such as a catheter. The imaging sequence may be for use in a cardiac region or the abdomen. The tracking sequence may further comprise a spatially non-selective excitation pulse followed by a magnetic field gradient pulse along a first spatial direction. |
IP Reference | GB2582795 |
Protection | Patent granted |
Year Protection Granted | 2020 |
Licensed | No |
Impact | NA |
Title | METHOD FOR USE IN CORRECTING A MAGNETIC RELAXATION TIME CONSTANT VALUE |
Description | Techniques are disclosed for determining coefficients for use in correcting a magnetic relaxation time constant, T, value obtained via magnetic resonance imaging when a pulse rate was at a first pulse rate value to a T value reflecting the T value that would have been obtained if the pulse rate was at a second pulse rate value. The technique includes, for each region of interest, pairing an obtained derivative, m, and an obtained offset, c, as an ordered pair (c, m). The technique further includes fitting the obtained plurality of ordered pairs (c, m) to a polynomial function, and determining the values of the coefficients from the polynomial function. |
IP Reference | US2020132796 |
Protection | Patent granted |
Year Protection Granted | 2020 |
Licensed | No |
Impact | NA |
Title | METHOD OF PERFORMING MAGNETIC RESONANCE IMAGING AND A MAGNETIC RESONANCE APPARATUS |
Description | In a method of performing magnetic resonance imaging and a magnetic resonance apparatus, first MR data are acquired of a region of interest of a subject in the absence of a B1 field. Second MR data are acquired of the region of interest in the presence of a B1 field, and within a short time interval after generation of the B1 field. The first and second MR data are processed to determine a B1 field map, and a T1 map is generated using the B1 field map. The T1 map is a B1 corrected T1 map. The first and second MR data 103, 109 may be acquired as part of a T1 mapping sequence, such as a MOLLI or SASHA type cardiac T1 mapping sequence. |
IP Reference | US2019064294 |
Protection | Patent granted |
Year Protection Granted | 2019 |
Licensed | No |
Impact | NA |
Title | METHOD OF PROCESSING MR IMAGES TO ESTIMATE A LONGITUDINAL RELAXATION TIME CONSTANT |
Description | A method of estimating a longitudinal magnetic relaxation T1 time for a region of a subject. The method includes providing a computer with at least two magnetic resonance (MR) images of the region of the subject that were respectively acquired at different times after the generation of a preparation pulse during a MR pulse sequence; in said computer, analyzing said at least two MR images in order to obtain, from the same location in each of the MR images, a pixel value, wherein each of the pixel values and the time at which their respective MR image was acquired form a data point; and in said computer, fitting the data points to a model representing said longitudinal magnetic relaxation by varying a single adjustable parameter to estimate the T1 time constant for the region of interest, wherein the single adjustable parameter represents a T1 time constant within the model. |
IP Reference | US2019369189 |
Protection | Patent granted |
Year Protection Granted | 2019 |
Licensed | No |
Impact | NA |
Title | Method and system for double contrast perfusion imaging |
Description | A method for cardiac perfusion imaging of a heart comprising: applying at least two saturation pulses during cardiac cycle; S110,S106 performing at least two image acquisitions S104,S110; each image acquisition taking place after one of the saturation pulses and after a different saturation time delay S102,S108; each image acquisition comprising simultaneously exciting at least two different slice locations in the heart and simultaneously obtaining at least two image slices. The step of performing at least two image acquisitions may comprise two-dimensional imaging, simultaneous multi-slice (SMS) imaging or three-dimensional imaging. The first image acquisition S104 may comprise simultaneously obtaining at least two image slices during a first cardiac phase which may be end-systole and the second image acquisition S110 may be during a second cardiac phase which may be mid-diastole. The step of performing at least two image acquisitions may comprise using any of the following readout modules balanced steady state free precession, gradient echo, and echoplanar imaging. |
IP Reference | GB2591300 |
Protection | Patent granted |
Year Protection Granted | 2021 |
Licensed | No |
Impact | NA |
Title | Method of performing magnetic resonance imaging and a magnetic resonance apparatus |
Description | In a method and apparatus for performing magnetic resonance (MR) imaging for generating multiple T1 maps of separate regions of interest of a subject along a first spatial axis, multiple MR pulse sequences are generated, each MR pulse sequence being for imaging a respective one of the separate regions of interest of the subject. In order to generate each of the plurality of MR pulse sequences, a spatially selective preparation pulse is generated exciting the region of interest of the subject and a number of imaging sequences that follow the application of the spatially selective preparation pulse are generated. MR imaging data are acquired during the generation of the multiple imaging sequences. The multiple MR pulse sequences are generated during a period not exceeding 30 seconds. |
IP Reference | US11194001 |
Protection | Patent granted |
Year Protection Granted | 2021 |
Licensed | No |
Impact | NA |
Description | IGT network |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Postgraduate students |
Results and Impact | Presentation at the Image-guided therapy (IGT) network which brought awareness of our iCMR work to the general post-graduate cohort in the UK interested in a much broader area of IGT. |
Year(s) Of Engagement Activity | 2019 |