A novel technique for the three-dimensional visualisation of radio-frequency ablation lesions using delayed enhancement magnetic resonance imaging (original) (raw)
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Medical Imaging 2009: Visualization, Image-Guided Procedures, and Modeling, 2009
The detection of radio-frequency ablation lesions has been shown to be feasible using delayed enhancement magnetic resonance imaging (MRI). However, it is the determination of the lesion patterns that is of import for correlation with clinical outcome and location of gaps. Visualisation of ablation patterns on twodimensional (2D) MR images is not intuitive. We present a technique for the three-dimensional (3D) visualisation of ablation patterns by creating a surface from a segmentation of the cardiac chamber of interest, fusing with the delayed enhancement MRI and integrating the MR signal along vectors normal to the cardiac surface. Areas of delayed enhancement will have a larger integral value than healthy myocardium. Maximum intensity projection (MIP) values were used to colour code the cardiac surface for 3D visualisation of the areas of delayed enhancement. The technique was applied to three patients with a cardiac arrhythmia, with successful visualisation of the ablation pattern. Patterns of delayed enhancement were correlated with ablation points derived from electro-anatomical mapping systems (EAMS) and were found to have similar patterns. This visualisation technique allows for the intuitive visualisation of ablation lesions and has many applications for use in electrophysiology.
2009
The detection of radio-frequency ablation lesions has been shown to be feasible using delayed enhancement magnetic resonance imaging (MRI). However, it is the determination of the lesion patterns that is of import for correlation with clinical outcome and location of gaps. Visualisation of ablation patterns on two-dimensional (2D) MR images is not intuitive. We present a technique for the three-dimensional (3D) visualisation of ablation patterns by creating a surface from a segmentation of the cardiac chamber of interest, fusing with the delayed enhancement MRI and integrating the MR signal along vectors normal to the cardiac surface. Areas of delayed enhancement will have a larger integral value than healthy myocardium. Maximum intensity projection (MIP) values were used to colour code the cardiac surface for 3D visualisation of the areas of delayed enhancement. The technique was applied to three patients with a cardiac arrhythmia, with successful visualisation of the ablation pattern. Patterns of delayed enhancement were correlated with ablation points derived from electro-anatomical mapping systems (EAMS) and were found to have similar patterns. This visualisation technique allows for the intuitive visualisation of ablation lesions and has many applications for use in electrophysiology.
IEEE Transactions on Biomedical Engineering, 2010
Catheter ablation using RF energy is a common treatment for atrial arrhythmias. Although this treatment provides a potential cure, currently, there remains a high proportion of patients returning for repeat ablations. Electrophysiologists have little information to verify that a lesion has been created in the myocardium. Temporary electrical block can be created from edema, which will subside. MRI can visualize acute and chronic ablation lesions using delayed-enhancement techniques. However, the ablation patterns cannot be determined from 2-D images alone.
Circulation. Arrhythmia and electrophysiology, 2012
Radiofrequency ablation is routinely used to treat cardiac arrhythmias, but gaps remain in ablation lesion sets because there is no direct visualization of ablation-related changes. In this study, we acutely identify and target gaps using a real-time magnetic resonance imaging (RT-MRI) system, leading to a complete and transmural ablation in the atrium. A swine model was used for these studies (n=12). Ablation lesions with a gap were created in the atrium using fluoroscopy and an electroanatomic system in the first group (n=5). The animal was then moved to a 3-tesla MRI system where high-resolution late gadolinium enhancement MRI was used to identify the gap. Using an RT-MRI catheter navigation and visualization system, the gap area was ablated in the MR scanner. In a second group (n=7), ablation lesions with varying gaps in between were created under RT-MRI guidance, and gap lengths determined using late gadolinium enhancement MR images were correlated with gap length measured from...
Technical note: on cardiac ablation lesion visualization for image-guided therapy monitoring
2018
The delivery of insufficient thermal dose is a significant contributor to incomplete tissue ablation and leads to arrhythmia recurrence and a large number of patients requiring repeat procedures. In concert with ongoing research efforts aimed at better characterizing the RF energy delivery, here we propose a method that entails modeling and visualization of the lesions in real time. The described image-based ablation model relies on classical heat transfer principles to estimate tissue temperature in response to the ablation parameters, tissue properties, and duration. The ablation lesion quality, geometry, and overall progression is quantified on a voxelby-voxel basis according to each voxel’s cumulative temperature and time exposure. The model was evaluated both numerically under different parameter conditions, as well as experimentally, using ex vivo bovine tissue samples. This study suggests that the proposed technique provides reasonably accurate and sufficiently fast visualiza...
T2*-weighted MRI technique for visualization of RF ablation lesions
Journal of Cardiovascular Magnetic Resonance, 2016
Background LGE-MRI is widely used to assess cardiac RF ablation lesions. However, LGE-MRI requires contrast injection and the appearance, dimensions and visibility of lesions in LGE-MRI noticeably change with time after ablation and time after contrast injection. Recently proposed non-contrast T1-weighted (T1w) technique is only applicable to visualize acute (< 3 days) RF lesions. The main goal of this study was to develop and validate a non-contrast MRI technique for assessment of sub-acute (> 3 days) RF ablations.
Magnetic resonance guided radiofrequency ablation: Creation and visualization of cardiac lesions
Lecture Notes in Computer Science, 1998
Current management of atrial fibrillation (AF) refractory to pharmacological therapy involves the creation of lines of conduction block in the atrial tissue either by direct surgical incision or fluoroscopy guided radiofrequency (RF) ablation. While these techniques have been shown to be effective in terminating atrial fibrillation, open heart surgery carries considerable inherent risk and fluoroscopy guided approaches are technically difficult and result in extremely long radiation exposure times. Magnetic resonance (MR) guided ablation therapy may represent a safer and more practical alternative for creating lines of conduction block in patients with AF. We have developed a novel MR compatible system that permits simultaneous high resolution MR imaging, cardiac electrical mapping, and RF energy delivery. This system has, for the first time, made it possible to perform a comprehensive MR guided electrophysiology study including guidance, delivery, and monitoring of cardiac ablation therapy.
Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance, 2018
Radiofrequency (RF) ablation has become a mainstay of treatment for ventricular tachycardia, yet adequate lesion formation remains challenging. This study aims to comprehensively describe the composition and evolution of acute left ventricular (LV) lesions using native-contrast cardiovascular magnetic resonance (CMR) during CMR-guided ablation procedures. RF ablation was performed using an actively-tracked CMR-enabled catheter guided into the LV of 12 healthy swine to create 14 RF ablation lesions. Tmaps were acquired immediately post-ablation to visualize myocardial edema at the ablation sites and T-weighted inversion recovery prepared balanced steady-state free precession (IR-SSFP) imaging was used to visualize the lesions. These sequences were repeated concurrently to assess the physiological response following ablation for up to approximately 3 h. Multi-contrast late enhancement (MCLE) imaging was performed to confirm the final pattern of ablation, which was then validated using...
Lecture Notes in Computer Science, 2005
Radio-frequency (RF) ablation uses electrode-catheters to destroy abnormally conducting myocardial areas that lead to potentially lethal tachyarrhythmias. The procedure is normally guided with x-rays (2D), leading to errors in location and excessive radiation exposure. One of our goals is to provide pre-and intra-operative 3D MR guidance in XMR systems (combined X-ray and MRI room) by locating myocardial regions with abnormal electrical conduction patterns. We address the inverse electro-mechanical relation by using motion in order to infer electrical propagation. For this purpose we define a probabilistic measure of the onset of regional myocardial activation derived from motion fields. The 3D motion fields are obtained using non-rigid registration of tagged MR sequences to track the heart. The myocardium is subdivided in segments and the derived activation isochrones maps compared. We also compare regional motion between two different image acquisitions, thus assisting in diagnosing arrhythmia, in follow up of treatment, and particularly in determining whether the electro-physiological intervention succeeded. We validate our methods using an electro-mechanical model of the heart, synthetic data from a cardiac motion simulator for tagged MRI, a cardiac MRI atlas of motion and geometry, MRI data from 6 healthy volunteers (one of them subjected to stress), and an MRI study on one patient with tachyarrhythmia, before and after RF ablation. Results seem to corroborate that the ablation had the desired effect of regularising cardiac contraction.
Journal of …, 2010
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)