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目的探索血氧水平依赖(BOLD)、体素内不相干运动(IVIM)、动脉自旋标记(ASL)磁共振技术研究小腿肌肉缺血灌注的可行性。方法对15名健康志愿者的一侧大腿根部给予不同程度压力,分别在加压前(P_0),收缩压基础上20 mmHg(P_(20))、收缩压基础上40 mmHg(P_(40))和释放压力后(Precovery)在3.0 T磁共振扫描仪上进行双小腿BOLD、IVIM和ASL成像。通过相应后处理软件对加压腿和对侧未加压小腿胫骨前肌、腓骨长肌、比目鱼肌、腓肠肌的BOLD-T_2~*值、IVIM-f值和ASL-BF值进行测量。通过经皮氧分压仪在成像区域测得4种状态下的经皮氧分压(TcPO_2)值作为对比参考。结果 4种不同状态下,加压侧小腿肌肉BF值、f值和T_2~*值都具有统计学意义(P<0.05),但胫骨前肌f值没有统计学意义。在P_(20)和P_(40)这两种状态下,加压侧小腿肌肉BF值和T_2~*值均明显低于加压前(P<0.008)而f值均高于加压前。在P_(40)状态下,加压侧和对照侧相比,除胫骨前肌T_2~*值无统计学意义外,其余肌肉BF值、f值和T_2~*值具有显著性差异。在P_(20)状态下加压侧和对照侧相比,两组腓肠肌的BF值和T_2~*值存在显著性差异。释放压力后所有的值趋向基线值。BF值和T_2~*值与TcPO_2呈正相关(分别ρ=0.465,P=0.001、ρ=0.522,P<0.001〗)。f值与TcPO_2呈负相关(ρ=-0.351,P=0.018)。结论 ASL-BF、BOLDT_2~*、IVIM-f值的变化可以评估小腿肌肉血流灌注情况,BF值和T_2~*值与TcPO_2值具有正相关性而f值与TcPO_2值具有负相关性。
Objective To explore the feasibility of studying the muscular ischemic perfusion in the lower leg with the blood oxygen level dependent (BOLD), the non-coherent motion within the voxel (IVIM) and the arterial spin labeling (ASL) magnetic resonance imaging. Methods Fifteen healthy volunteers were given different degrees of pressure on the thighs. The pressure of 40 mmHg (P 40) was calculated on the basis of systolic pressure and 20 mmHg (P 20) before systolic pressure (P 0) ) And post-release (Precovery) dual-leg BOLD, IVIM and ASL imaging on a 3.0 T MRI scanner. The BOLD-T 2 * value, IVIM-f value and ASL-BF value of the ankle tibial anterior tibialis, peroneus longus, soleus muscle and gastrocnemius were measured by corresponding post-processing software. The percutaneous oxygen partial pressure (TcPO_2) values of the four states measured by the percutaneous oxygen pressure meter in the imaging area were taken as a reference for comparison. Results The BF value, f value and T_2 ~ * value of the calf muscles in the pressure side were statistically significant (P <0.05) under four different conditions, but the f value of tibialis anterior muscle had no statistical significance. Under P_ (20) and P_ (40) conditions, BF and T_2 ~ * values of calf muscle in pressure side were significantly lower than those before pressure (P <0.008) and f values were higher than those before pressure. Compared with the control side, there was significant difference in BF value, f value and T_2 ~ * value of muscle in P_ (40) state, except T_2 ~ * of tibialis anterior muscle was not statistically significant. In the P 20 state, the BF and T 2 - * values of the gastrocnemius muscle were significantly different between the pressure side and the control side. After releasing the pressure all the values tend towards the baseline value. BF and T_2 ~ * values were positively correlated with TcPO_2 (ρ = 0.465, P = 0.001, ρ = 0.522, P <0.001, respectively). The value of f was negatively correlated with TcPO_2 (ρ = -0.351, P = 0.018). Conclusion The changes of ASL-BF, BOLDT_2 ~ * and IVIM-f can evaluate the blood perfusion of calf muscles. There is a positive correlation between BF value and T_2 ~ * value and TcPO_2 value, while f value has a negative correlation with TcPO_2 value.