Karczmar GS, Fan X, Al-Hallaq HA, Zamora M, River JN, Rinker-Schaeffer C, Zaucha M, Tarlo K, Kellar K. Uptake of a superparamagnetic contrast agent imaged by MR with high spectral and spatial resolution. Magn Reson Med. 2000 May; 43(5):633-9.