RESUMO
PURPOSE: Late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (MRI) studies were performed on healthy individuals to establish signal intensity thresholds for reproducible left atrial (LA) patchy LGE detection. Using established criteria, differences in LA patchy LGE between healthy volunteers (HV) and patients with atrial fibrillation (AF) or hypertension were analyzed. METHODS: Fifty-three patents with AF (mean age 56 years, 60% men), 25 patients with hypertension and no history of AF (mean age 54 years, 40% men), and 28 HV (mean age 50 years, 52% men) were enrolled in an observational, non-interventional, case-control prospective study. LA patchy LGE quantification was performed using LGE MRI (1.5 T scanner, voxel size 1.25x1.25x2.5 mm) and the custom-built software based on estimation of LA voxel image intensity ratio and comparison with threshold value obtained from HV data. RESULTS: Based on analysis of healthy individuals' data, the optimal threshold value for the left atrial patchy LGE quantification was determined at 1.38. Patients with AF had a higher extent of LA patchy LGE (9.1 [1.72; 18.58] %) than patients with hypertension (3.81 [0.57; 9.51] %) and HV (0.78 [0.05; 3.5] %). The predominant location of LA patchy LGE in AF was in the pulmonary vein ostia region, in hypertension - LA posterior wall, and in HV - lower part of LA posterior wall. In AF patients, the extent of LA patchy LGE correlated with LA end-diastolic volume (r=0.37) and LA ejection fraction (r=-0.4), in HV - with age (r=0.66) and LA end-diastolic volume (r=0.4). CONCLUSION: AF and hypertension are associated with higher extent and different location of LA patchy LGE compared to changes caused by natural aging. The extent of LA patchy enhancement correlates with LA dilatation.
RESUMO
BACKGROUND: In the recent years, there has been an increasing number of publications postulating that data on left atrial (LA) structure obtained by late gadolinium enhancement magnetic resonance imaging (LGE MRI) can improve the management of patients with atrial fibrillation (AF). At the same time, similar data regarding healthy LA myocardium is limited. AIM: To assess structural and functional properties of LA in healthy volunteers (HV) using cardiac magnetic resonance (CMR) (including LGE MRI); to compare these properties in patients with AF and HV. MATERIALS AND METHODS: We included in this study 53 patients with AF (28 without signs of cardiovascular disease, 28 with hypertension) and 23 HV of similar age. All enrolled persons underwent MRI. Cine-MRI was used to assess end diastolic volume of LA (LA EDV), LA ejection fraction (LA EF), left ventricular diastolic index (LV DI). High resolution LGE MRI was performed 15-20 min after gadoversetamide injection using IR 3D gradient echo pulse sequence with fat saturation (TI 290-340 ms, TE 2.44 ms, TR 610-1100ms). On obtained images LA was segmented semiautomatically. LA fibrosis quantification was performed using developed software LGE Heart Analyzer. The extent of fibrosis was represented as percent of LA myocardium volume. Fibrosis location was determined on reconstructed rotating 3D LA model. RESULTS: Compared with patients HV had lower LA EDV (59 [54; 78] ml and 79 [65.5; 86.6] ml, Ñ=0.043, respectively), higher LA EF (56.1 [49; 63.2] % and 44.5 [34.5, 54.5] %, Ñ=0.03, respectively), and lower extent of LA fibrosis (0.7 [0.05; 3.5] % and 9.1 [1.7; 18] %, Ñ.