Application of a 2D frequency encoding sectoral approach to hyperpolarized 129Xe MRI at low field

• Published in: Journal of magnetic resonance (1997) 2022-03, Vol.336, p.107159-107159, Article 107159
• Main Authors: Perron, Samuel, Ouriadov, Alexei, Wawrzyn, Krzysztof, Hickling, Susannah, Fox, Matthew S., Serrai, Hacene, Santyr, Giles
• Format: Article
• Language: English
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2022.107159

[Display omitted] •Frequency Encoding Sectoral (FES) is a fast, ultra short-TE, Cartesian pulse sequence.•Both 1H &129Xe FES provide high image quality compared to FGRE at low field (0.074 T).•FES is a promising imaging method for in vivo hyperpolarized 129Xe low field lung MRI.•FES drawbacks (blurring and white pixels) caused by the MRI hardware can be overcome.•FES can be extended for human scans at higher fields utilizing a long 129Xe T2*-decay. Inhaled hyperpolarized 129Xe MRI is a non-invasive and radiation risk free lung imaging method, which can directly measure the business unit of the lung where gas exchange occurs: the alveoli and acinar ducts (lung function). Currently, three imaging approaches have been demonstrated to be useful for hyperpolarized 129Xe MR in lungs: Fast Gradient Recalled Echo (FGRE), Radial Projection Reconstruction (PR), and spiral/cones. Typically, non-Cartesian acquisitions such as PR and spiral/cones require specific data post-processing, such as interpolating, regridding, and density-weighting procedures for image reconstruction, which often leads to smoothing effects and resolution degradation. On the other hand, Cartesian methods such as FGRE are not short-echo time (TE) methods; they suffer from imaging gradient-induced diffusion-weighting of the k-space center, and employ a significant number of radio-frequency (RF) pulses. Due to the non-renewable magnetization of the hyperpolarized media, the use of a large number of RF pulses (FGRE/PR) required for full k-space coverage is a significant limitation, especially for low field (