磁共振中脑导水管脑脊液流动成像在正常小儿的研究分析

Magnetic resonance imaging flow quantification of normal pediatric midbrain aqueduct cerebruspinal fluid in children

目的分析正常小儿中脑导水管处脑脊液磁共振流动成像表现，并进一步了解脑脊液的循环过程及原理。方法使用3T超导磁共振机器（西门子verio）对正常小儿中脑导水管进行磁共振脑脊液流动成像检查。按其年龄分为〈1．5岁（14例）和1．5～14岁（25例）两组。磁共振检查序列包括经过中脑导水管的横断位、矢状位和冠状位T2WI像，经过中脑导水管的矢状位3D-CISS序列和相位对比-电影序列（PC-Cine），以及垂直中脑导水管截面的相位对比-电影序列。观察各组的影像学改变和脑脊液电影循环情况，并测定每组小儿中脑导水管的截面积、脑脊液不同方向峰流速及净流量，比较两组数据有无统计学差异。结果在经过中脑导水管矢状位和垂直中脑导水管截面的PC-Cine序列上均可观察到在一个心动周期内脑脊液信号呈明暗交替变化，心脏收缩期峰流速方向向下，舒张期方向向上。1．5～14岁组脑脊液向下峰流速为（8．371±1．511）cm／s显著高于〈1．5岁组（6．538±1．264）cm／s，差异有统计学意义（P=0．0005）；1．5～14岁组向上峰流速为（7．163±1．806）cm／s略高于〈1．5岁组（6．073±1．096）cm／s，差异亦有统计学意义（P=0．0475），小儿中脑导水管的截面积和净流量在两组间差异无统计学意义（P〉0．05）。结论磁共振脑脊液流动成像能清晰的显示中脑导水管脑脊液循环过程，为了解小儿脑脊液循环特点及疾病进展提供准确的影像依据。

Objective To measure cerebrospinal fluid （CSF） flow through normal pediatric midbrain aqueduct using magnetic resonance imaging （MRI） and to provide insight into CSF hydrodynamics and theory. Methods A total of 25 normal children aged from 1.5 to 14 years were compared with 14 normal controls aged from 8 months to 1.5 years. MRI flow quantifieations were performed. T2WI, 3D-CISS and PC-Cine sequences （midbrain aqueduct level and through midhrain aqueduct level） were examined by 3. 0T superconductive magnetic resonance scanner. At midhrain aqueduct level,aqueductal area （mm2）, peak flow velocity （cm/s） and net flow volume （ml/cycle） were studied. Results The direction and signal intensity of CSF flow changed with PC-Cine during cardiac cycle in normal children. The direction of flow was downward during systolic period and upward flow during diastolic period. The outflow peak velocity was significantly higher in 1.5-14 years group than that in 〈1.5 years group （8. 371 ± 1.511 vs 6. 538 ± 1.264 cm/s,P = 0. 0005）. In 1.5-14 years group, the inflow peak velocity was of a similar magnitude higher than 〈1.5 years group （7. 163 ± 1. 806 vs 6. 073 ± 1. 096 cm/s,P = 0. 0475）. No inter-group difference existed in aqueduetal area or net flow volume （P〉0. 05）. Conclusions The patterns of aqueduct CSF flow support the current theories of CSF hydrodynamics in children. And MR PC-Cine may provide an accurate diagnosis of CSF circulatory diseases.