Balanced UTE-SSFP for 19F MR Imaging of Complex Spectra

Purpose A novel technique for highly sensitive detection of multiresonant fluorine imaging agents was designed and tested with the use of dual-frequency F-19/1H ultrashort echo times (UTE) sampled with a balanced steady-state free precession (SSFP) pulse sequence and three-dimensional (3D) radial readout. Methods Feasibility of 3D radial balanced UTE-SSFP imaging was demonstrated for a phantom comprising liquid perfluorooctyl bromide (PFOB). Sensitivity of the pulse sequence was measured and compared with other sequences imaging the PFOB (CF2)(6) line group including UTE radial gradient-echo (GRE) at a?=? 30 degrees, as well as Cartesian GRE, balanced SSFP, and fast spin-echo (FSE). The PFOB CF3 peak was also sampled with FSE. Results The proposed balanced UTE-SSFP technique exhibited a relative detection sensitivity of 51 inline imagemin-1/2 (a?=?30 degrees), at least twice that of other sequence types with either 3D radial (UTE GRE: 20 inline imagemin-1/2) or Cartesian k-space filling (GRE: 12 inline imagemin(-1/2); FSE: 16 inline imagemin-1/2; balanced SSFP: 23 inline imagemin-1/2). In vivo imaging of angiogenesis-targeted PFOB nanoparticles was demonstrated in a rabbit model of cancer on a clinical 3 Tesla scanner. Conclusion A new dual 19F/1H balanced UTE-SSFP sequence manifests high SNR, with detection sensitivity more than two-fold better than traditional techniques, and alleviates imaging problems caused by dephasing in complex spectra. Magn Reson Med 74:537543, 2015. (C) 2014 Wiley Periodicals, Inc.