Magnetic resonance imaging of the membranous labyrinth during in vivo gadolinium (Gd-DTPA-BMA) uptake in the normal and lesioned cochlea

MRI with a T-1 contrast agent was used to investigate the normal and noise- damaged cochlea. The time course and distribution of the in vivo uptake of the gadodiamide chelate bound paramagnetic Gd ion (GdDTPA-BMA) throughout t he membranous labyrinth of normal and impulse noise-damaged guinea pig coch leae were measured by MRI at 4.7 T. Simultaneous signal enhancement of the basal, medial and apical scala tympani (ST) and scala vestibuli (SV) was ob served within 10 min following i.v. injection, reaching maximum levels at a round 100 min. ANOVA and post hoc paired t-tests showed statistically signi ficant differences in the levels and rates of Gd uptake-enhancement between the scalae. The ST revealed the most rapid and extensive enhancement throu ghout the period of active Gd uptake, while the SV showed comparatively slo wer and less enhancement, and the intact scala media (SM) indicated insigni ficant enhancement. The in vivo Gd penetration and enhancement of the membr anous SM increased significantly in the noise-damaged cochlea, suggesting l esioning of the cochlear membranes. NeuroReport 11:3979-3983 (C) 2000 Lippi ncott Williams & Wilkins.