Institute of Cardiometabolism And Nutrition, La Pitié-Salpêtrière Hospital, Paris, France.
Sorbonne University, INSERM 1146, CNRS 7371, Laboratoire d'Imagerie Biomédicale, Paris, France.
PLoS One. 2018 Oct 8;13(10):e0205104. doi: 10.1371/journal.pone.0205104. eCollection 2018.
Atrial fibrillation is associated with an atrial cardiomyopathy composed mainly of fibrosis and adipose tissue accumulation. We hypothesized that MRI, when used in an optimal ex vivo setting allowing high spatial resolution without motion artifacts, can help characterizing the complex 3D left atrial (LA) wall composition in human myocardial samples, as compared to histology.
This prospective case-control study was approved by the institutional review board. 3D MRI acquisitions including saturation-recovery T1 mapping and DIXON imaging was performed at 4.0 T on 9 human LA samples collected from patients who underwent cardiac surgery. Histological quantification of fibrosis and fat was obtained. MRI T1 maps were clustered based on a Gaussian Mixture Model allowing quantification of total, interstitial and fatty fibrosis components. Fat maps were computed from DIXON images and fat fractions were calculated. MRI measurements were performed on the same location as the histological analysis (plane) and on the entire sample volume (3D).
High correlations and levels of agreement were observed between MRI and histology for total (r = 0.93), interstitial (r = 0.93) and fatty fibrosis (r = 0.98) and fat (r = 0.96). Native T1 correlated with the amount of fibrosis from MRI and histology. The 3D MRI total, interstitial and fatty fibrosis ranges were between 6% and 23%, 4% and 17.3%; and 1.4% and 19.7% respectively.
High Field ex vivo MRI was able to quantify different LA myocardial components with high agreement in 2D with histology and moreover to provide 3D quantification of such components whereas in vivo application remains a challenge.
心房颤动与主要由纤维化和脂肪组织堆积组成的心房心肌病有关。我们假设，在允许高空间分辨率而无运动伪影的最佳离体设置下使用 MRI 可以帮助对人体心肌样本的复杂 3D 左心房（LA）壁组成进行特征描述，与组织学相比。
这项前瞻性病例对照研究得到了机构审查委员会的批准。在 4.0 T 上对从接受心脏手术的患者中收集的 9 个人 LA 样本进行了包括饱和恢复 T1 映射和 DIXON 成像的 3D MRI 采集。获得了纤维化和脂肪的组织学定量。根据高斯混合模型对 MRI T1 图进行聚类，从而可以定量总、间质和脂肪纤维化成分。从 DIXON 图像计算脂肪图，并计算脂肪分数。MRI 测量是在与组织学分析相同的位置（平面）和整个样本体积（3D）上进行的。
MRI 和组织学之间在总（r = 0.93）、间质（r = 0.93）和脂肪纤维化（r = 0.98）和脂肪（r = 0.96）方面观察到高度相关性和一致性。固有 T1 与 MRI 和组织学上的纤维化量相关。3D MRI 的总、间质和脂肪纤维化范围分别为 6%-23%、4%-17.3%和 1.4%-19.7%。
高磁场离体 MRI 能够在 2D 上与组织学高度一致地定量不同的 LA 心肌成分，并且能够提供这些成分的 3D 定量，而体内应用仍然是一个挑战。
