颅脑外伤后视神经蛛网膜下腔扩张与颅内压增高的MRI相关性研究

MRI correlative study of dilated subarachnoid space of optic nerve with intracranial pressure in craniocerebral injury

目的:探讨颅脑外伤患者眶内段视神经蛛网膜下腔扩张与颅内压增高的关系。方法:14例颅脑外伤并颅内压增高及蛛网膜下腔出血患者,在伤后2d内进行MRI检查,并在斜冠状位重T2加权图像上测量视神经球后4mm、10mm、16mm处蛛网膜下腔的外径,MRI检查结束后4h内进行腰穿,在施放脑脊液前测量脑脊液压力。经保守治疗6～14d,临床症状明显好转后,再重复一次MRI检查及腰穿脑脊液压力测定,对所得数据进行统计分析。结果:14例颅脑外伤并急性颅内压增高患者,首次检查脑脊液压力为2.31±0.24kPa,视神经眶内段前、中、后各测量点蛛网膜下腔的外径(左右侧平均值)分别为6.5±0.5mm、5.5±0.5mm、4.9±0.5mm,由前向后逐渐变窄(P<0.01)。经保守治疗好转后,脑脊液压力降低为1.75±0.21kPa,此时各测量点蛛网膜下腔外径分别为4.2±1.0mm、3.6±0.9mm、3.2±0.7mm,较首次检查明显变窄(P<0.01)。前、中、后各测量点的蛛网膜下腔的外径与脑脊液压力的相关系数分别为0.864、0.858、0.837(P<0.01)。结论:眶内段视神经蛛网膜下腔扩张程度与颅内压呈显著的正相关关系,可作为临床评价颅脑损伤患者颅内压增高程度的定量指标。

Objective:To study the correlation between dilated subarachnoid space of intraorbital optic nerve and intracranial pressure in craniocerebral injury.Methods:Fourteen cases of patients associated with intracranial hyperpressure and subarachnoid hemorrhage were undergone the first MRI scanning and lumbar puncture within 2 days after injury.The width of subarachnoid space at the points of 4mm,10mm,16mm retrobulbarly were measured on FSE T2 weighted oblique-coronal images.The cerebrospinal fluid(CSF) pressure was measured before drainage.The second MRI scanning and measurement was undergone after 6～14 days of conservative treatment when symptoms relieved.The data thus obtained was statistically processed.Results:Of all the 14 cases of acute intracranial hyperpressure patients,the CSF pressure was 2.31 ± 0.24kPa in the first examination.The diameters of subarachnoid space (mean of right and left) at the points of 4mm,10mm,16mm retrobulbarly were 6.5 ± 0.5mm,5.5 ± 0.5mm and 4.9 ± 0.5mm respectively,varied from wide in anterior part to narrow in posterior part of the orbit (P<0.01).The CSF pressure decreased to 1.75 ± 0.21kPa after conservative treatment.The diameters of subarachnoid space at the points of 4mm,10mm,16mm retrobulbarly decreased to 4.2 ± 1.0mm,3.6 ± 0.9mm,3.2 ± 0.7mm respectively (P<0.01).Conclusion:The dilation of the subarachnoid spaces of intraorbital optic nerve was well correlated with intracranial!pressure and it could serve as an important quantitative imaging evidence for intracranial hyperpressure.