Journal Article

Differentiation and quantification of fibrosis, fat and fatty fibrosis in human left atrial myocardium using ex vivo MRI

Cluzel, Philippe, Defrance, Carine, Kachenoura, Nadjia, Hatem, Stéphane N., Kusmia, Slawomir, Evin, Morgane, Atassi, Fabrice, Bouazizi, Khaoula, Leprince, Pascal, Lebreton, Guillaume, Redheuil, Alban, Berthet, Myriam, Rahhal, Amer

2018

Overview

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.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Adipose tissue / Adipose Tissue - diagnostic imaging / Adipose Tissue - pathology / Atrial fibrillation / Bioaccumulation / Bioengineering / Biology and Life Sciences / Cardiac arrhythmia / Cardiology / Cardiology and cardiovascular system / Cardiomyopathy / Case-Control Studies / Control methods / Diagnosis, Differential / Fibrillation / Fibrosis / Fibrosis - diagnostic imaging / Fibrosis - pathology / Health aspects / Heart Atria - diagnostic imaging / Heart atrium / Heart Diseases - diagnostic imaging / Heart Diseases - pathology / Heart Diseases - surgery / Heart surgery / Histology / Human health and pathology / Humans / Hypertension / Image Interpretation, Computer-Assisted / Imaging / Imaging, Three-Dimensional / Life Sciences / Magnetic Resonance Imaging / Medical imaging / Medicine and Health Sciences / Metabolism / Myocardium / Myocardium - pathology / NMR / Nuclear magnetic resonance / Nutrition / Probabilistic models / Prospective Studies / Research and Analysis Methods / Spatial discrimination / Spatial resolution / Surgery / Thoracic surgery