Application of Cine Phase Contrast MRI in Spontaneous Intracranial Hypotension Before and After Treatment

Abstract

Spontaneous intracranial hypotension (SIH) is characterized by orthostatic headache. Typical abnormal magnetic resonance imaging (MRI) findings have been considered to be the sine qua non of SIH, but a sizeable minority of patients has normal results using conventional MRI. The purpose of this study was to evaluate the difference in cerebrospinal fluid (CSF) flow dynamics between patients and healthy people using cine phase contrast (PC) MRI, and to assess the CSF flow dynamics in patients before and after treatment. From November of 2007 to December of 2012, twenty patients with SIH (10 men and 10 women, mean age=40.9±7.77 years) and 31 age- and gender- matched healthy subjects (15 men and 16 women, mean age=46.3±7.53 years) were enrolled in this retrospective study. Cine PC MRI was performed on the patients and on the healthy subjects to measure the CSF flow in cerebral aqueduct. Patients underwent repeated cine PC MRI at 24 hours and at one month after treatment respectively. Five parameters including peak positive and negative velocity, average flow, and average positive and negative flow were recorded to evaluate their differences. Seventeen patients (85%) received epidural blood patching (EBP) owing to the failure of conservative treatment. All patients experienced resolution of symptoms after treatment. Before treatment, the patients had a significantly lower average CSF flow than the healthy subjects (p＜0.001). The average CSF flow was elevated in patients with SIH at 24 hours after treatment and was significantly increased one month after treatment (p=0.003). By establishment of the receiver operating characteristic (ROC) curve, the best cutoff value for the average CSF flow was determined to be 14.0μl/beat, while the sensitivity and specificity were determined to be 90.3% and 72.2%, respectively. Patients with SIH showed lower CSF flow compared to healthy subjects, but this decreased CSF flow was shown by cine PC MRI to be gradually recovered after treatment. This study provides evidence that cine PC MRI is useful for assessing the dynamic changes of CSF flow in the cerebral aqueduct noninvasively and for demonstrating the effectiveness of treatment in patients with SIH reliably.