体素内非相干运动(IVIM)扩散加权成像对骨骼肌运动血流灌注变化的相关性研究

Correlation between non-coherent motion within a voxel(IVIM) diffusion-weighted imaging skeletal muscle movement perfusion changes

目的旨在探究以IVIM加权成像无创性评价骨骼肌静息状态及运动后其灌注功能、扩散功能的改变情况。方法 15名健康志愿者,在静息状态下对其前臂行IVIM序列扫描,然后于标准化手柄运动后立即行IVIM扫描。将扫描图像传入工作站,于指浅/深屈肌、肱桡肌及桡侧腕长伸肌选取感兴趣区(ROI),分别重复计算各肌肉运动前后的弥散系数(D)、假扩散系数(D*)及灌注分数(Fp),并得到各参数的伪彩图。不同肌群组各数据的差异及不同时间点同组肌群各数据的差异使用重复测量方差分析,统计各差异是否有统计学意义。结果静息状态下的各参数值如下:D*为(28.4±11.0)×10-3mm2/s,Fp为0.03±0.01,D为(1.45±0.08)×10-3mm2/s;运动后各IVIM参数发生明显变化,在指浅/深屈肌(FDS/FDP),D*增加279±225%(P<0.029),Fp增加136±55%(P<0.01),D增加18±9%(P<0.01)。肱桡肌的各IVIM参数同样有相应的增高,但程度低于FDS/FDP。20 min后,FDS/FDP各IVIM参数仍处于高值状态,但是肱桡肌各IVIM参数与静息状态下相比无明显差异。结论 IVIM扩散加权成像可以同时无创性的提供肌肉静息状态及运动后其灌注及弥散功能的变化情况,为应用于类似周围血管闭塞等与肌肉血流灌注相关的疾病提供可能。

Objective：The purpose of this work was to evaluate the feasibility of intravoxel incoherent motion imaging （ IVIM）for quantification of perfusion and diffusion effects noninvasivly in skeletal muscle at rest and following exercise. Methods：Fifteen healthy volunteers underwent diffusion-weighted MRI of the forearm at rest,then,after a standardized handgrip exercise,dynamic images were acquired. Diffusion（ D）and pseudodiffusion（ D＊）coefficients as well as the per-fusion fraction（ Fp）were measured in regions of interest in different skeletal muscle by using the workstation,with paramet-rical maps produced. Differences in D,D＊,and FP between muscle groups and between time points were calculated using a repeated measures analysis of variance with post hoc Bonferroni tests. Results：Mean values and standard deviations at rest were the following：D＊（28. 4 ± 11. 0）× 10-3 mm2/s,Fp（0. 03 ± 0. 01）,D（1. 45 ± 0. 08）× 10-3 mm2/s;three param-eters changed after exercising：In the FDS/FDP,D＊ increased by（279 ±225%）（P﹤0.029）,Fp by（136 ±55%）（P﹤0. 01）,and D by（18 ± 9%）（P﹤0. 01）. A significant increase of IVIM parameters could also be detected in the bra-chioradialis muscle,which however was significantly lower than in the FDS/FDP. After 20 min,all parameters were still significantly elevated in the FDS/FDP but not in the brachioradialis muscle compared with the resting state. Conclusion：The IVIM approach allows simultaneous quantification of muscle perfusion and diffusion effects at rest and following exercise, thus,it is possibile to be used in perfusion-related muscle diseases,such as peripheral arterial occlusive disease.