钆对比剂顺磁性弛豫增强效能比较的体模研究

Comparison of Efficiency of Paramagnetic Relaxation Enhancement of Gadolinium-Based Contrast Agents:a Phantom Study

【目的】比较5种常用钆对比剂(GBCAs)在实验室条件下在相同的稀释比和摩尔浓度下的顺磁性弛豫增强效能。【方法】收集5种常用GBCAs,包括2种线性及3种大环类GBCAs,并按照相同稀释比用蒸馏水将其制备成相同摩尔浓度的体模。在3.0 T MR扫描仪上对人体志愿者及5组体模按照相同扫描方案和参数进行扫描后,在图像后处理工作站上画ROI测量体模、邻近小腿肌肉和周围空气的T_(1)WI信号强度和T_(1)值,并计算T_(1)WI相对信号强度(RSI)和T_(1)-mapping的T_(1)弛豫速率(R_(1))、计算信噪比(SNR)、对比噪声比(CNR)。分析5组体模溶液信号强度(Sp)、RSI、T_(1)值、R_(1)、SNR、CNR与GBCAs摩尔浓度的相关性,并比较5种GBCAs之间的Sp、RSI、T_(1)值、R_(1)、SNR和CNR的差异。【结果】5种GBCAs配备成相同摩尔浓度的稀释液,钆布醇原液使用容积最小。5种GBCAs的Sp、RSI与摩尔浓度均呈曲线相关(r_(s)=0),T_(1)值、SNR与摩尔浓度呈负相关(r_(s<)0),R_(1)、CNR和摩尔浓度呈正相关(r_(s)>0)。5种GBCAs之间的Sp、RSI、T_(1)值、R_(1)、SNR和CNR的差异无统计学意义,线性与大环类GBCAs之间的Sp、RSI、T_(1)值、R_(1)、SNR和CNR的差异无统计学意义。【结论】5种线性和大环类GBCAs蒸馏水体模在相同摩尔浓度下的T_(1)WI信号强度和T_(1)值无差异,并且过高和过低的GBCAs摩尔浓度都将使体模的T_(1)WI信号强度下降,而T_(1)值会随摩尔浓度的增加而持续下降。

【Objective】To compare the efficiency of paramagnetic relaxation enhancement of five gadolinium-based contrast agents(GBCAs)at the same dilution ratio and molar concentration.【Methods】Five commonly used GBCAs,including 2 linear and 3 macrocyclic GBCAs,were employed and prepared to phantoms with the same molar concentration and dilution rate using distilled water.The phantoms were scanned in a 3.0 T MRI scanner under the same sequences and parameters.The regions of interest(ROIs)were drawn on the T_(1)WI SE and T_(1) mapping images to quantitatively measure the T_(1)WI signal intensity and T_(1) value from phantoms,calf muscles and surrounding air.The T_(1) relaxation rate(R_(1)),signal to noise ratio(SNR)and contrast noise ratio(CNR)were then calculated based on the T_(1)WI signal intensity and T_(1) value.The relationship from signal intensity(Sp),RSI,T_(1) value,R_(1),SNR,CNR and molar concentration were analyzed.The differences from Sp,RSI,T_(1) value,R_(1),SNR,CNR in 5 GBCAs were compared.【Results】In the process of phantoms’s preparation,the total used dose of Gd-DO3A-butrol was lowest.Sp and RSI were curvilinearly correlated with the molar concentration of GBCAs(r_(s)=0).While T_(1)p and SNR were negatively correlated with the molar concentration of GBCAs(r_(s)<0),R_(1) and CNR were positively correlated with the molar concentration of GBCAs.The Sp,T_(1) values,RSI,SNR and CNR from these five GBCAs were detected to be similar to each other,even between linear and macrocyclic GBCAs.【Conclusions】Under the same molar concentration,there are no significant difference of T_(1)WI signal intensity and T_(1) value between linear and macrocyclic GBCAs phantoms found from Magnetic resonance imaging.What’s more,both high and low molar concentration of gadolinium-based contrast agents can decrease the T_(1)WI signal intensity of phantom,but the T_(1) value will continue to decrease with the increase of the molar concentration.