Fluorinated Gas MR Imaging at Ultra Short Echo Time: Initial Results on a 1.5 T Clinical System

Pascal Hagot¹, Ludovic De Rochefort¹, Jean-Christophe Ginefri¹, Rose-Marie Dubuisson¹, Marie Poirier-Quinot¹, Jean-Pierre Ruaud¹, Hongchen Wang¹, Xavier Matre¹, Luc Darrasse¹

Using inert fluorinated gas as sulfur hexafluoride have proven its feasibility without the need of polarizing the gas thanks to its short T1 (few ms) that allows rapid repetition of RF pulse and thus a high number of signal averages. On the other hand, its short T2* ~ 1 ms reduces significantly the available time to acquire NMR signal after an excitation RF pulse. To overcome this constraint, ultra-short echo time sequences can be used. Preliminary UTE experiments using SF6 on a clinical 1.5T scanner and show the significant gain over standard gradient-echo acquisition.