Time course for measuring endolymphatic size in healthy volunteers following intravenous administration of gadoteridol.
OBJECTIVE
We developed semi-quantitative methods to measure endolymphatic size on images obtained 4 hours after intravenous administration of single-dose gadolinium-based contrast medium (IV-SD-GBCM) and found little variation in results between observers. We used the methods to measure the size of the endolymph in healthy volunteers at various times after IV-SD-GBCM and attempted to determine the optimal timing for the evaluation.


METHODS
In 8 healthy male volunteers, we obtained heavily T2-weighted 3-dimensional fluid-attenuated inversion recovery (hT2W-3D-FLAIR) images 1.5, 3, 4.5, and 6 hours after IV-SD-GBCM as positive perilymph images (PPI) as well as acquiring positive endolymph images (PEI) and magnetic resonance cisternography (MRC). To evaluate the endolymph, we generated 2 kinds of processed images (HYDROPS-Mi2 and HYDROPS2-Mi2) by subtracting PEI or MRC from PPI as previously proposed. We semi-quantitatively measured the ratio of the area of the endolymph (%EL) to that of total lymph on the 2 kinds of generated images for the cochlea and vestibule according to the previously proposed method. We analyzed statistics to evaluate the change in %EL over time and used analysis of variance (ANOVA) for a 2 × 4 repeated-measures design to assess difference in image type. We adopted 5% as a significance level.


RESULTS
The %EL was significantly larger at 1.5 hours after IV-SD-GBCM than at 3, 4.5, and 6 hours in both the cochlea and vestibule for both kinds of generated images. Between 4.5 and 6 hours, the %EL plateaued for both the cochlea and vestibule, and the 2 kinds of generated images did not differ significantly.


CONCLUSIONS
A delay of 1.5 hours after IV-SD-GBCM is not sufficient to evaluate endolymphatic size. The %EL plateaus between 4.5 and 6 hours. These data might be valuable for further clinical studies.
Department of Radiology, Nagoya University Graduate School of Medicine.
Shinji
S
Naganawa
Kojiro
K
Suzuki
Masahiro
M
Yamazaki
Yasuo
Y
Sakurai
Mitsuru
M
Ikeda
D000328:Adult; D003287:Contrast Media / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004710:Endolymph / Q000378:metabolism*; D018159:Endolymphatic Hydrops / Q000473:pathology; D005682:Gadolinium / Q000008:administration & dosage / Q000493:pharmacokinetics; D064368:Healthy Volunteers; D006571:Heterocyclic Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics*; D006801:Humans; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D007275:Injections, Intravenous; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015588:Observer Variation; D009942:Organometallic Compounds / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013997:Time Factors
D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium