正常中脑导水管脑脊液流动磁共振定量研究

MR quantitative study of normal aqueduct cerebrospinal fluid flow

目的 :运用磁共振相位对比电影法非侵袭性测量中脑导水管脑脊液流动方向、流速及流量改变情况。方法 :测量 15例正常志愿者 (年龄 2 1～ 4 7岁 ,平均 31 4岁 )中脑导水管脑脊液流动情况 ,在正中矢状位T1WI图像上选择垂直于导水管层面 ,编码速率 2 0cm/s。测量相应层面导水管截面积 ,计算相应导水管区脑脊液流量 ,并研究在一个心动周期内CSF流动改变情况。结果 :正常中脑导水管脑脊液流动在一个心动周期内表现为双向流动 ,即收缩期向下流动和舒张期向上流动 ,收缩期平均向下峰流速和舒张期平均向上峰流速分别为 12 6 7± 3 5 8mm/s和 11 5 8± 3 96mm/s,平均向下及向上流量分别为 1 311± 0 74 0ml/min(0 0 18± 0 0 12ml/心动周期 )和 1 0 6 8± 0 5 6 8ml/min(0 0 14± 0 0 0 9ml/心动周期 ) ,平均净流量为 0 2 6 0± 0 2 4 9ml/min(0 0 0 4± 0 0 0 4ml/心动周期 ) ;脑脊液向下流动平均最大峰速发生在一个心动周期的R波后平均 18%时间点 (心动周期的 5 7ms,平均心动周期 85 7ms) ,向上最大峰流速出现在心动周期的 87%时间点 (心动周期的6 86ms,平均心动周期 85 7ms) ,而逆向流动发生在R波后平均 4 4 %～ 5 8%时间点 (心动周期的 343～ 4 5 7ms,平均心动周期85 7ms)。结论 :磁共振相位对比?

Objective:To measure the CSF flow of the aqueduct by MR phase-contrast cine (PC-cine) technique.Methods:15 healthy volunteers (21 to 47 years of age, average 31.4 years) were studied. The aqueduct cerebrospinal fluid flow image was positioned perpendicular to the midbrain aqueduct at the middle sagittal T 1WI image. This pulse sequence used a velocity encoding of 20cm/s. The waveforms were analyzed for the maximum flow velocity, flow volume and the change of the figures.From the velocity and area measurements on the cine images, mean CSF flow were calculated in millimeters per second and milliliters per cardiac cycle.Results:The normal CSF flow of the aqueduct has two directions which is downward (caudal) flow during the systolic period and upward (cranial) flow during the diastolic period of the cardiac cycle. The out and in flow peak velocity were 12.67±3.58mm/s and 11.58±3.96mm/s respectively. The mean out and in flow volume were 1.311±0.740ml/min (0.018±0.012ml/cycle) and 1.068±0.568ml/min (0.014±0.009ml/cycle) respectively, mean net flux was 0.260±0.249/min (0.004±0.004ml/cycle). The peak velocity of downward (caudal) CSF flow during the systolic period was appeared at 57ms during the cardiac cycle, while the peak velocity of upward (cranial) CSF flow was appeared at the 686ms of the cardiac cycle after the peripheral triggered.Conclusion:MR PC-cine technique provides a direct quantitative technique to evaluate the CSF flow and also enrich the diagnosis information of CSF circulation diseases.