鼓室注射Gd-DTPA后内耳MRI增强强度与造影剂浓度关系体外试验初步探讨

A Preliminary in Vitro Study of the Relationship between MRI Contrast Enhancement and Gd-DTPA Concentration in the Inner Ear after Transtympanic Delivery

目的为探讨鼓室注射钆喷酸葡胺(Gd-DTPA)内耳增强显影的造影剂药物代谢动力学,设计体外试验探索造影剂浓度与核磁信号增强强度之间的相关性。方法配制不同浓度Gd-DTPA溶液,行3D-T1 FSE序列扫描后使用核磁工作站读取图像信号强度(SI),并将其与造影剂浓度行相关性及回归分析。结果 Gd-DT-PA在较低浓度范围内(≤1 mmol/L),SI与造影剂浓度呈良好的线性关系,并得到回归方程:Y=23 388X+8 120.1(决定系数r2=0.96,Y为SI;X为Gd-DTPA浓度,单位mmol/L)。结论应用此体外试验所得的回归方程,将鼓室注射造影剂后内耳扫描获得的增强信号强度转化为造影剂浓度,即可用来研究造影剂内耳药物代谢动力学规律。

Objective To explore whether there is any correlation between MRI contrast enhancement and Gd-DTPA concentration,for further study of the pharmacokinetic characteristics of MRI contrast agent in inner ear.Methods Tubes filled with different concentrations of Gd-DTPA were scanned through MRI using 3D-T1 FSE sequence,signal intensities（SI） were obtained using GE workstation,then coefficient of determination（r^2） and linear regression equation between SI and Gd-DTPA concentration were calculated.Results When Gd-DTPA concentration was low,SI correlated well with concentration of the Gd-DTPA（Y=23 388X＋8 120.1,r^2=0.96,Y represents SI;X represents Gd-DTPA concentration,unit mmol/L）.Conclusion Signal intensity in inner ear which was enhanced by Gd-DTPA through transtympanic delivery can be converted into different concentrations of Gd-DTPA,which could be another way for the pharmacokinetic study in inner ear.