Masahiro Yamazaki MD, Presenter: Nothing to Disclose

Shinji Naganawa MD, Abstract Co-Author: Nothing to Disclose

Hisashi Kawai, Abstract Co-Author: Nothing to Disclose

Tsutomu Nakashima MD, PhD, Abstract Co-Author: Nothing to Disclose

Gadolinium contrast agent (Gd) injected either by intratympanically or intravenously distributes preferentially in perilymph space. 3D-FLAIR images obtained 24 hours after intratympanic Gd injection (IT-method) and 4 hours after intravenous injection (IV-method) have been utilized to visualize the endolymphatic hydrops in Ménière’s disease. The purpose of this study was to evaluate the difference of Gd distribution in cochlear perilymph between two methods by comparing the degree of enhancement of basal and apical turn perilymph.

Thirty-nine clinically suspected Ménière’s disease patients included in this study. 22 patients who underwent IT-method (Gd-DTPA was diluted 8-fold with saline) and 17 patients who underwent IV-method (a double-dose of Gd-HP-DO3A (0.5mmol/ml); 0.2 mmol/kg body weight in total amount) at 3 Tesla were analyzed retrospectively. The evaluations were performed only on clinically affected and gadolinium injected side cochleae. 24 ears of IT-method and 28 ears of IV-method patients were evaluated. ROI of the perilymph of cochlear basal turn (B), that of apical turn (A), and medulla oblongata (M) were determined on each patient, and the signal intensity ratio between A and B (ABR), B and M (BMR), A and M (AMR) were subsequently evaluated.

IV-method ABR (0.84 ± 0.22) was higher than IT-method ABR (0.58 ± 0.17) (p<0.001). IT-method BMR (2.63 ± 1.22) was higher than IV-method BMR (1.46 ± 0.45) (p<0.001). There was no significant difference between IT- (1.46 ± 0.76) and IV-method AMR (1.21 ± 0.48) (p=0.15).

The results of the present study suggest that IV-method would provide homogenous distribution of Gd in cochlear perilymph than IT-method. Although IT-method would provide higher perilymph enhancement than IV-method on basal turn in general, the variation of contrast effect on IV-method was smaller than that on IT-method. On apical turn, the contrast effect of perilymph was not different between IT- and IV-method.

IV-method provides images with stable quality for the evaluation of endolymphatic hydrops in Ménière’s disease, because the distribution of Gd in cochlear perilymph would be homogenous.

Yamazaki, M, Naganawa, S, Kawai, H, Nakashima, T, Distribution of Gadolinium Contrast Agent in Cochlear Perilymph: Comparison of Intratympanic and Intravenous Gadolinium Injection.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11034210.html