- Poster presentation
- Open Access
Dynamic TI for late gadolinium enhancement imaging in atrial fibrillation
© Keegan et al; licensee BioMed Central Ltd. 2012
- Published: 1 February 2012
- Atrial Fibrillation
- Late Gadolinium Enhancement
- Late Gadolinium Enhancement Imaging
- Longitudinal Magnetisation
- Repeat Time Interval
There has been considerable interest in high resolution 3D late gadolinium enhancement (LGE) imaging in the atrial fibrillation (AF) population, both pre and post RF ablation. Unlike conventional studies, these are performed with single R-wave gating to reduce the acquisition duration and the effects of gadolinium wash-out. For AF, the heart rate variability results in variable magnetization recovery between sequence repeats which, with a fixed inversion time (TI), causes ghosting and poor nulling of normal tissue. This is exacerbated by missed triggers and the number of poor quality studies is high. An adaptive inversion recovery preparation has previously been demonstrated in a 2D phantom acquisition . The purpose of this study is to implement such a technique (dynamic_TI) for improved imaging in the AF population.
An inversion-prepared segmented FLASH sequence was modified so that the inversion time was varied automatically from beat-to-beat based on the time since the last sequence repeat . The gating delay was also modified for each cardiac cycle so that the timing of the acquisition window remained fixed. The sequence was demonstrated in a phantom mimicking a short axis slice of the myocardium and in patients with fast AF. Acquisitions were performed with single R-wave gating, both with and without the dynamic_TI algorithm. For phantom studies, both 2D and 3D data were acquired, while in vivo, time constraints only allowed the acquisition of 2D studies. The sequence repeat times were stored for subsequent simulation of the evolution of the longitudinal magnetisation through the acquisition.
We have shown that dynamic adaptation of the inversion time for each cardiac cycle is feasible and results in less ghosting and improved nulling of normal myocardium in 2D acquisitions in the AF population. Application to 3D studies should result in improved acceptability rates.
Wellcome Trust(grant reference: P32451) and NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.