Preliminary exploration of Gd-DTPA enhanced inner ear image of guinea pig using magnetic resonance scan
10.3760/cma.j.issn.1673-0860.2011.08.012
- VernacularTitle:豚鼠内耳钆喷酸葡胺MRI显像的初步探讨
- Author:
Chang DONG
1
;
Yang LIU
;
Qing-Quan HUA
;
Wei LIN
;
Jian-Jun SUN
;
Wei-Ning HUANG
;
Fang LIU
;
Xu-Hui LIU
Author Information
1. 武汉大学人民医院
- Keywords:
Gadolinium DTPA;
Magnetic resonance imaging;
Ear,inner;
Pharmacokinetics;
Guinea pigs
- From:
Chinese Journal of Otorhinolaryngology Head and Neck Surgery
2011;46(8):669-674
- CountryChina
- Language:Chinese
-
Abstract:
Objective To observe the distribution of Gd-DTPA in the inner ear of guinea pig by MRI at different time points after intratympanic administration, explore the optical time for observing the whole inner ear. To study the pharmacokinetic feature of Gd-DTPA in the inner ear, and find out whether discrimination of endolymph and perilymph can be obtained under current conditions. Methods Sixty-five guinea pigs were randomly divided into 13 groups, after diluted Gd-DTPA intratympanic injection, each group of guinea pigs were scanned through MRI(3D-T1 FSE sequence) at different time points(0 h, 0. 5 h,1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 24 h, 48 h, 72 h, 96 h). Pixel intensity values of some locations in the inner ear were analyzed using e-Film software, then pixel intensity was converted into concentration using the results of previous in-vitro study. ABR thresholds of bilateral ears before, 1 d and 7 d after intratympanic injection were compared. Results Six hours after transtympanic Gd-DTPA injection was the time point when contrast agent was distributed all over the inner ear, and reached a high concentration: 589. 29,552. 54, 570. 17,255.08, 107.09 and 139. 18 μmol/L in the vestibule, scala vestibuli and scala tympani of basal turn, the 2nd, the 3rd and the apical turn individually, that was also the optimal time for observing the whole inner ear by MRI. Perilymph appeared to be preferentially enhanced relative to the endolymph,resulting in a distinction between the scalaes of the inner ear. There was no significant difference between the experimental ear( diluted GD-DTPA injected ear) and contrast ear( physiological saline injected ear) on 1 d and 7 d. Conclusions The best time getting MRI imaging after intratympanic diluted GD-DTPA injection is 6 h. After diluted agent injection perilymph can be enhanced so as to be differentiated with endolymph by MRI, diluted agent have no obvious effect on the ABR threshold. The pharmacokinetic feature of Gd-DTPA in the inner can be studied using MRI.
