Visualization of LPS+Gd-DOTA in the middle ear cavity and inner ear of rat after transtympanic injection using T1-weighted 2D MRI. LPS+Gd-DOTA nanoparticles (1.0 mM LPS+Gd-DOTA containing 500 mM Gd-DOTA) were delivered to the left middle ear. At 3 h time point (A-C), they were detected in the middle ear cavity, vestibule, and cochlea. Aftert 6 h (D-F), these regions with uptake of nanoparticles showed brighter signal and the second turn and apex of the cochlea became more visible. 1st: the basal turn; 2nd: the second turn; BS: brainstem; L: left ear; ME: middle ear; R: right ear; ST: scala tympani; SV: scala vestibuli; Vest: vestibule. Particle sizes = 150 ± 20 nm. Scale bar = 1 mm.