Simple Estimation of the Endolymphatic Volume Ratio after Intravenous Administration of a Single-dose of Gadolinium Contrast

抄録

Purpose: To evaluate the feasibility of a simple estimation for the endolymphatic volume ratio (endolymph volume/total lymph volume = %EL_volume) from an area ratio obtained from only one slice (%EL_1slice) or from three slices (%EL_3slices). The %EL_volume, calculated from a time-consuming measurement on all magnetic resonance (MR) slices, was compared to the %EL_1slice and the %EL_3slices.
Methods: In 40 ears of 20 patients with a clinical suspicion of endolymphatic hydrops, MR imaging was performed 4 hours after intravenous administration of a single dose of gadolinium-based contrast material (IV-SD-GBCM). Using previously reported HYDROPS2-Mi2 MR imaging, the %EL_volume values in the cochlea and the vestibule were measured separately by two observers. The correlations between the %EL_1slice or the %EL_3slices and the %EL_volume values were evaluated.
Results: A strong linear correlation was observed between the %EL_volume and the %EL_3slices or the %EL_1slice in the cochlea. The Pearson correlation coefficient (r) was 0.968 (3 slices) and 0.965 (1 slice) for observer A, and 0.968 (3 slices) and 0.964 (1 slice) for observer B (P < 0.001, for all). A strong linear correlation was also observed between the %EL_volume and the %EL_3slices or the %EL_1slice in the vestibule. The Pearson correlation coefficient (r) was 0.980 (3 slices) and 0.953 (1 slice) for observer A, and 0.979 (3 slices) and 0.952 (1 slice) for observer B (P < 0.001, for all). The high intra-class correlation coefficients (0.991–0.997) between the endolymph volume ratios by two observers were observed in both the cochlea and the vestibule for values of the %EL_volume, the %EL_3slices and the %EL_1slice.
Conclusion: The %EL_volume might be easily estimated from the %EL_3slices or the %EL_1slice.