Fast low-angle positive contrast steady-state free precession imaging of USPIO-labeled macrophages: theory and in vitro experiment - Mascheri, Nicole; Dharmakumar, Rohan; Zhang, Zhuoli; Paunesku, Tatjana; Woloschak, Gayle; Li, Debiao (Magnetic Resonance Imaging (0730725X), 2009)