MR无对比剂肾动脉血管成像的参数优化及其与年龄的关系

Parameter optimization for non-contrast-enhanced renal MR angiography and its relationship with age

目的探讨利用时间—空间双重标记翻转恢复(Time-SLIP)技术进行MR无对比剂肾动脉血管成像的可行性,得出最佳反转时间(TI)值,并分析其与年龄的关系。方法将61名健康志愿者按年龄分为22~50岁组(n=32)及51~80岁组(n=29),分别于6个不同TI值(1 200、1 300、1 400、1 500、1 600、1 700ms)水平下行MR扫描。分别测量及分析肾血管—肾实质信号强度比(VKR)、肾动脉分支显示评分及肾动脉图像质量评分。结果左侧及右侧肾的VKR值均在TI值为1 500ms时最高。肾动脉分支显示评分在TI值为1 200~1 400ms水平逐渐上升,之后趋于平缓。全部受试者中,TI值为1 500ms时图像质量评分最高;22~50岁组中,TI值为1 500ms时肾动脉图像质量评分最高;51~80岁组中,TI值为1 600ms时肾动脉图像质量评分最高。22~50岁组各部分肾动脉图像质量评分均高于51~80岁组(P均<0.05)。结论利用Time-SLIP技术可在不使用对比剂的情况下完成MR肾动脉成像,最佳TI值为1 500ms。年龄是影响TI值选择的重要因素之一。

Objective To investigate the feasibility of non-contrast-enhanced renal MR angiography （NCE-MRA） using time spatial labeling inversion pulse （Time-SLIP） technique, and to discuss the optimized inversion time （TI） and its relationship with age. Methods A total of 61 healthy volunteers were divided into two groups by age, 22—50 years （n=32） and 51—80 years （n=29）. All volunteers underwent 3.0T MRI examination with 6 different TIs sequences （1 200, 1 300, 1 400, 1 500, 1 600, 1 700 ms）. The vessel-to-kidney signal ratio （VKR）, grade of renal artery branches, grade of renal artery imaging quality were measured and analyzed. Results The VKR values were the highest at TI=1 500 ms in both sides of kidneys. The scores of renal artery branches were gradually rising up but tending to be steady higher than 1 400 ms. Among all the subjects, the highest score of renal artery imaging quality was at TI=1 500 ms. In 22—50 years group, the highest score of renal artery imaging quality was at TI=1 500 ms. Meanwhile, the highest score was found at TI=1 600 ms in 51—80 years group. Moreover, the grade of renal artery imaging in the 22—50 years group acquired better scores compared to the 51—80 years group （all P〈0.05）. Conclusion Time-SLIP technique is helpful to obtain renal MRA without contrast medium. The optimized TI value is 1 500 ms. Moreover, age can affect the optimized TI value.