Accelerated 3d left atrial late gadolinium enhancement in patients with atrial fibrillation at 1.5 t: Technical development

Abstract

Purpose: To develop an accelerated three-dimensional (3D) late gadolinium enhancement (LGE) pulse sequence using balanced steady-state free precession readout with stack-of-stars k-space sampling and extra motion-state golden-angle radial sparse parallel (XD-GRASP) reconstruction and test the performance for detecting atrial scar and fibrosis in patients with atrial fibrillation (AF). Materials and Methods: Twenty-five patients with AF (20 paroxysmal and five persistent; 65 years 6 7 [standard deviation]; 18 men) were imaged at 1.5 T using the proposed LGE sequence with 1.3 mm 3 1.3 mm 3 2-mm spatial resolution and predictable imaging time. The resulting images were compared with historic images of 25 patients with AF (18 paroxysmal and seven persistent; 67 years 6 10; 14 men) obtained using a reference 3D left atrial (LA) LGE sequence with 1.3 mm 3 1.3 mm 3 2.5-mm spatial resolution. Two readers visually graded the 3D LGE images (conspicuity, artifact, noise) on a five-point Likert scale (1 = worst, 3 = acceptable, 5 = best), in which the summed visual score (SVS) of 9 or greater was defined as clinically acceptable. Appropriate statistical analyses (Cohen k coef-ficient, Mann-Whitney U test, t tests, and intraclass correlation) were performed, where a P value, .05 was considered significant. Results: Mean imaging time was significantly shorter (P, .01) for the proposed pulse sequence (5.9 minutes 6 1.3) than for the reference pulse sequence (10.6 minutes 6 2). Median SVS was significantly higher (P, .01) for the proposed (SVS = 11) than reference (SVS = 9.5) 3D LA LGE images. Interrater reproducibility in visual scores was higher for the proposed (k = 0.78–1) than reference 3D LA LGE (k = 0.44–0.75). Intrareader repeatability in fibrosis quantification was higher for the reference cohort (intraclass correlation coefficient [ICC] = 0.94) than the prospective cohort (ICC = 0.79). Conclusion: The proposed 3D LA LGE method produced clinically acceptable image quality with 1.5 mm 3 1.5 mm 3 2-mm nomi-nal spatial resolution and 6-minute predictable imaging time for quantification of LA scar and fibrosis in patients with AF.