Different uptake of unpurified and purified LPS+Gd-DOTA in rat inner ear after transtympanic injection shown by MPR single view of T1-weighted 3D MR imaging. Unpurified LPS+Gd-DOTA were efficiently taken up in the inner ear at 40 min after transtympanic injection at a concentration of 1 mM (containing 500 mM Gd-DOTA) (A and B). The signal intensity of purified LPS+Gd-DOTA (B and C) in the inner ear was significantly lower than that of unpurified LPS+Gd-DOTA judged by vision. LW: lateral wall; Mod: modiolus; MPR: multiplanar reconstruction; SM: scala media; ST: scala tympani; SV: scala vestibuli; Vest: vestibule; SCCs: semicircular canals; unpur: unpurified LPS+Gd-DOTA; pur: purified LPS+Gd-DOTA. Particle sizes = 300 ± 20 nm. Sacle bar = 500 μm.