HEAD AND NECK RADIOLOGY Gadolinium distribution in cochlear perilymph: differences between intratympanic and intravenous gadolinium injection Masahiro Yamazaki & Shinji Naganawa & Hisashi Kawai & Michihiko Sone & Tsutomu Nakashima Received: 23 April 2012 / Accepted: 23 July 2012 / Published online: 3 August 2012 # Springer-Verlag 2012 Abstract Introduction Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging 24 h after intratympanic gad- olinium injection (IT method) or 4 h after intravenous injec- tion (IV method) has been used to visualize endolymphatic hydrops in Ménière’ s disease. The aims of this study were to evaluate the difference in gadolinium distribution in cochlear perilymph between the two methods by comparing the en- hancement of the basal and apical turns and clarify the phar- macokinetics in cochlear perilymph. Methods A total of 24 ears of 22 patients who underwent the IT method (gadolinium-diethylene-triamine pentaacetic acid was diluted eightfold with saline) and 28 ears of 17 patients who underwent the IV method (double dose of gadoteridol (0.5 mmol/ml); 0.2 mmol/kg body weight in total amount) at 3 T was analyzed retrospectively. Regions of interest of the perilymph of the cochlear basal turn (B), of the apical turn (A), and the medulla oblongata (M) were determined on each patient. The signal intensity ratios be- tween B and M (BMR), A and M (AMR), and A and B (ABR) were subsequently evaluated. Results The IT-BMR (2.63±1.22) was higher than the IV- BMR (1.46±0.45) (p <0.001). There was no significant dif- ference between the IT- (1.46±0.76) and IV-AMRs (1.21± 0.48) (p 0 0.15). The IT-ABR (0.58±0.17) was lower than the IV-ABR (0.84±0.22) (p <0.001). Conclusion Gadolinium was predominantly distributed in the basal turn compared with the apical turn in the IT method, whereas it was more uniformly distributed in the IV method. These characteristics might reflect the distribution of thera- peutic medications administered either intratympanically or systemically. Keywords Magnetic resonance imaging . Three- dimensional fluid-attenuated inversion recovery (3D-FLAIR) . Intratympanic gadolinium injection . Intravenous gadolinium injection . Cochlear pharmacokinetics Introduction Three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) imaging can minimize the undesired ghosts of fluid flow [1] and enable recognition of the subtle compositional changes and the contrast effect in the lymph fluid in the inner ear [2–4]. 3D-FLAIR imaging 24 h after intratympanic gadolinium injection (IT meth- od) has been reported to visualize perilymph and endo- lymph fluid separately and to identify the presence of endolymphatic hydrops [ 5–7]. 3D-FLAIR has been reported to be suited for contrast enhancement assess- ment 24 h after intratympanic gadolinium injection [8]. On the other hand, 3D-FLAIR imaging 4 h after intra- venous gadolinium injection (IV method) has also been recently reported to visualize endolymphatic hydrops [9, 10]. The characteristics of the distribution of gadolinium in the cochlear perilymph after intratympanic or intra- venous injection might reflect the distribution of thera- peutic medications administered either intratympanically or systemically, such as gentamicin or steroids [11–16]. However, to the best of our knowledge, a detailed M. Yamazaki (*) : S. Naganawa : H. Kawai Department of Radiology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan e-mail: yamazaki@med.nagoya-u.ac.jp M. Sone : T. Nakashima Department of Otorhinolaryngology, Nagoya University Graduate School of Medicine, Nagoya, Japan Neuroradiology (2012) 54:1161–1169 DOI 10.1007/s00234-012-1078-9