Trajectory correction enables free-running chemical shift encoded imaging for accurate cardiac proton-density fat fraction quantification at 3T

• Published in: Journal of cardiovascular magnetic resonance 2024, Vol.26 (2), p.101048, Article 101048
• Main Authors: Daudé, Pierre, Troalen, Thomas, Mackowiak, Adèle L.C., Royer, Emilien, Piccini, Davide, Yerly, Jérôme, Pfeuffer, Josef, Kober, Frank, Gouny, Sylviane Confort, Bernard, Monique, Stuber, Matthias, Bastiaansen, Jessica A.M., Rapacchi, Stanislas
• Format: Article
• Language: English
• Subjects: Adipose Tissue - diagnostic imaging; Adiposity; Adult; Aged; Bioengineering; Cardiac fat-water MRI; Case-Control Studies; Computer Simulation; Epicardial adipose tissue; Female; Free-running MRI; Gradient impulse response function; Humans; Image Interpretation, Computer-Assisted; Imaging; Life Sciences; Magnetic Resonance Imaging; Magnetic Resonance Imaging, Cine; Male; Middle Aged; Original Research; Pericardium - diagnostic imaging; Phantoms, Imaging; Predictive Value of Tests; Protons; Reproducibility of Results
• ISSN: 1097-6647; 1532-429X; 1532-429X
• DOI: 10.1016/j.jocmr.2024.101048

Metabolic diseases can negatively alter epicardial fat accumulation and composition, which can be probed using quantitative cardiac chemical shift encoded (CSE) cardiovascular magnetic resonance (CMR) by mapping proton-density fat fraction (PDFF). To obtain motion-resolved high-resolution PDFF maps, we proposed a free-running cardiac CSE-CMR framework at 3T. To employ faster bipolar readout gradients, a correction for gradient imperfections was added using the gradient impulse response function (GIRF) and evaluated on intermediate images and PDFF quantification. Ten minutes free-running cardiac 3D radial CSE-CMR acquisitions were compared in vitro and in vivo at 3T. Monopolar and bipolar readout gradient schemes provided 8 echoes (TE1/ΔTE = 1.16/1.96 ms) and 13 echoes (TE1/ΔTE = 1.12/1.07 ms), respectively. Bipolar-gradient free-running cardiac fat and water images and PDFF maps were reconstructed with or without GIRF correction. PDFF values were evaluated in silico, in vitro on a fat/water phantom, and in vivo in 10 healthy volunteers and 3 diabetic patients. In monopolar mode, fat-water swaps were demonstrated in silico and confirmed in vitro. Using bipolar readout gradients, PDFF quantification was reliable and accurate with GIRF correction with a mean bias of 0.03% in silico and 0.36% in vitro while it suffered from artifacts without correction, leading to a PDFF bias of 4.9% in vitro and swaps in vivo. Using bipolar readout gradients, in vivo PDFF of epicardial adipose tissue was significantly lower compared to subcutaneous fat (80.4 ± 7.1% vs 92.5 ± 4.3%, P < 0.0001). Aiming for an accurate PDFF quantification, high-resolution free-running cardiac CSE-MRI imaging proved to benefit from bipolar echoes with k-space trajectory correction at 3T. This free-breathing acquisition framework enables to investigate epicardial adipose tissue PDFF in metabolic diseases. [Display omitted]