Optimal Techniques for Late Gadolinium-Enhanced MRI: Comparison of Delay Time, Slice Thickness, and Multiplanar Reconstruction vs Maximum Intensity Projection for Assessment of Fibrosis in Atrial Fibrillation

Abstract

Background Left atrial (LA) late gadolinium enhancement (LGE) magnetic resonance imaging (MRI) has varying protocols, which may limit interstudy comparisons. This study evaluates whether changes in image acquisition and reconstruction parameters affect quantification of LA LGE MRI. Methods A total of 200 LGE MRI scans were prepared using various techniques from 5 subjects. 3D respiratory and ECG-gated LGE images were acquired at 15, 20, 25, and 30 minutes after contrast. Multiplanar reconstructions (MPR) and maximum intensity projections (MIP) were created from 3D data at various slice thicknesses. LA LGE was quantified with image intensity ratio (IIR, atrial wall signal intensity divided by blood pool). Mean IIR was calculated for the entire LA as a metric of LGE burden. Additionally, in 42 consecutive preablation patients, local IIR values from 3.5-mm MPR and MIP reconstructions were separately registered to LA electroanatomic voltage maps (EAM) obtained prior to ablation procedure. Results Multitime point LGE-MRI showed a rise in baseline mean IIR of 0.5% ± 0.1% per minute ( P P P P Conclusions Variations in timing of acquisition, image reconstruction methods, and slice thickness result in changes in LA LGE quantity.