Spectrally selective three‐dimensional dynamic balanced steady‐state free precession for hyperpolarized C‐13 metabolic imaging with spectrally selective radiofrequency pulses

Purpose Balanced steady‐state free precession (bSSFP) sequences can provide superior signal‐to‐noise ratio efficiency for hyperpolarized (HP) carbon‐13 (13C) magnetic resonance imaging by efficiently utilizing the nonrecoverable magnetization, but managing their spectral response is challenging in the context of metabolic imaging. A new spectrally selective bSSFP sequence was developed for fast imaging of multiple HP 13C metabolites with high spatiotemporal resolution. Theory and Methods This novel approach for bSSFP spectral selectivity incorporates optimized short‐duration spectrally selective radiofrequency pulses within a bSSFP pulse train and a carefully chosen repetition time to avoid banding artifacts. Results The sequence enabled subsecond 3D dynamic spectrally selective imaging of 13C metabolites of copolarized [1‐13C]pyruvate and [13C]urea at 2‐mm isotropic resolution, with excellent spectral selectivity (∼100:1). The sequence was successfully tested in phantom studies and in vivo studies with normal mice. Conclusion This sequence is expected to benefit applications requiring dynamic volumetric imaging of metabolically active 13C compounds at high spatiotemporal resolution, including preclinical studies at high field and, potentially, clinical studies. Magn Reson Med 78:963–975, 2017. © 2016 International Society for Magnetic Resonance in Medicine.