Ablation Lesion Assessment with MRI

Abstract

Late gadolinium enhancement (LGE) MRI is capable of detecting not only native cardiac fibrosis, but also ablation-induced scarring. Thus, it offers the unique opportunity to assess ablation lesions non-invasively. In the atrium, LGE-MRI has been shown to accurately detect and localise gaps in ablation lines. With a negative predictive value close to 100% it can reliably rule out pulmonary vein reconnection non-invasively and thus may avoid unnecessary invasive repeat procedures where a pulmonary vein isolation only approach is pursued. Even LGE-MRI-guided repeat pulmonary vein isolation has been demonstrated to be feasible as a standalone approach. LGE-MRI-based lesion assessment may also be of value to evaluate the efficacy of ventricular ablation. In this respect the elimination of LGE-MRI-detected arrhythmogenic substrate may serve as a potential endpoint, but validation in clinical studies is lacking. Despite holding great promise, the widespread use of LGE-MRI is still limited by the absence of standardised protocols for image acquisition and post-processing. In particular, reproducibility across different centres is impeded by inconsistent thresholds and internal references to define fibrosis. Thus, uniform methodological and analytical standards are warranted to foster a broader implementation in clinical practice.

Tissue characterization of acute lesions during cardiac magnetic resonance-guided ablation of cavo-tricuspid isthmus-dependent atrial flutter: a feasibility study

“…The most established hypothesis is that the destroyed microvasculature prevents gadolinium to be present at the central ablation core, while there is a peripheral rim of hyper-enhancement due to contrast entering the ablation lesions via diffusion from the lesion periphery. 11 , 33 Histological analysis of ablation lesions in the left ventricle of pigs demonstrated that the peripheral rim of hyper-enhancement reflects oedema in the border zone of the acute lesion, which would fit studies reporting LGE areas to be larger in the acute phase than in chronic ablation scar. 34 In our study, 2D LGE was performed, despite its lower spatial resolution, as a useful alternative to time-consuming 3D LGE.…”

State of the Art and New Advances: Cardiac MRI

“…Patients presenting with arrhythmias causing SCD from a variety of etiologies benefit from a CMR to identify and understand myocardial characteristics and abnormalities. In patients with arrhythmias, mapping techniques, such as T1/T2, can identify edema, necrosis, and scarring contributing to arrhythmias [44] which is further enhanced by identification of LGE in DE imaging. Further characterization of these lesions and anatomical geometry with CMR also allows for stratifying patients most suitable for ablation [45], along with identifying focus of arrhythmia to assist with ablation procedures.…”

Pulsed field ablation for atrial fibrillation – Lessons from magnetic resonance imaging

“…Cardiovascular magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE) is an established scientific tool in the analysis of myocardial fibrosis representing atrial cardiomyopathy as well as ablation-induced atrial scar formation following catheter ablation with thermal energy sources. 5 In this review article, assessment and validation of PFA-induced lesions based on CMR and the needs to adopt imaging approaches to the cellular mechanisms of electroporation are discussed.…”

“…Cardiovascular magnetic resonance imaging (CMR) using late gadolinium enhancement (LGE) is an established scientific tool in the analysis of myocardial fibrosis representing atrial cardiomyopathy as well as ablation‐induced atrial scar formation following catheter ablation with thermal energy sources 5 …”