大鼠血清和生理盐水中Mn^(2+)浓度与MRI弛豫率变化的关系

Relationship of Mn^(2+) concentration and MRI relaxation ratio in rat serum and saline

目的探讨在大鼠血清和生理盐水中Mn^(2+)浓度与MR T1值及弛豫率间的变化关系。方法配制Mn^(2+)浓度为0、0.1、0.2、0.3、0.4、0.5、0.6、0.7及0.8 mmol/L的生理盐水和大鼠血清样本,采用小动物MR成像仪对各样本行T1W及T1-mapping成像,测量各样本T1值,并计算弛豫率。比较相同Mn^(2+)浓度时2种介质间和不同Mn^(2+)浓度间T1值的差异,并分析Mn^(2+)浓度与弛豫率的关系。结果 Mn^(2+)浓度为0时,生理盐水呈低信号,大鼠血清呈中等信号;随着Mn^(2+)浓度升高,生理盐水和大鼠血清的T1W信号均逐渐增高,大鼠血清T1WI信号上升更快。相同Mn^(2+)浓度的2种介质间,大鼠血清的T1值均小于生理盐水(P均<0.001)。大鼠血清和生理盐水中,不同Mn^(2+)浓度样本间T1值差异均有统计学意义(P均<0.001),随着Mn^(2+)浓度增大,T1值均逐渐减小,两两Mn^(2+)浓度间比较差异均有统计学意义(P均<0.001)。大鼠血清及生理盐水中,Mn^(2+)浓度与弛豫率呈近似线性关系。结论 Mn^(2+)可缩短大鼠血清和生理盐水这2种液体介质的T1值,且Mn^(2+)浓度与弛豫率呈线性关系。

Objective To explore the relationship of Mn 2+concentration and MRI T1 value and relaxation ratio in rat serum and saline.Methods All samples of rat serum and saline containing Mn 2+concentration of 0,0.1,0.2,0.3,0.4,0.5,0.6,0.7 and 0.8 mmol/L were prepared and used for T1W and T1-mapping imaging with a small animal MR instrument,the T1 value of each sample was measured,and relaxation ratio was calculated.The difference of T1 value between these two medium containing the same Mn 2+concentration and medium containing different Mn 2+concentration were compared,and the relationship between Mn 2+concentration and relaxation ratio was analyzed.Results With the absence of Mn 2+,saline showed low signal intensity and rat serum showed medium signal intensity on T1WI.As Mn 2+concentration increased,T1WI signal intensity of both saline and rat serum increased gradually,and T1WI signal intensity of rat serum in rats increased faster.T1 value of rat serum was lower than that of normal saline(all P<0.001)of every Mn 2+concentration.T1 values in rat serum and saline containing different Mn 2+concentrations were statistically different(both P<0.001).When Mn 2+concentration increased,T1 value decreased gradually,and the difference between any two Mn 2+concentration were all statistically significant(all P<0.001).The relaxation ratio showed nearly a linear dependence on Mn 2+concentration in rat serum and saline.Conclusion Mn 2+can shorten T1 value of rat serum and saline,and relaxation ratio has a linear relationship with Mn 2+concentration.