Abstract
Purpose: :
Although lumbar puncture is a simple way to measure the cerebrospinal fluid pressure (CSF-P), it requires invasive procedures. The subarachnoid space around the optic nerve is connected with the whole CSF circulation system and can be visualized using T2-weighted MRI. By measuring the optic nerve sheath diameter (ONSD), optic nerve diameter (OND) with 3.0-Tesla MRI, the authors investigated the relationship between the MRI measurements and lumber puncture CSF-P. A noninvasive monitoring tool of CSF-P by index of optic nerve MRI measurement may be feasible in the future.
Methods: :
35 subjects examined in the Neurological Department underwent MRI of the brain and optic nerve, followed by the lumbar pressure measurement for diagnostic reasons. For all the subjects, at least one optic nerve was normal. ONSD and OND were determined at 3mm, 9mm and 15mm behind the eye ball with T2-weighted fast recovery fast spin echo (FRFSE) fat suppressed sequence in 3.0-Tesla MRI. Optic nerve subarachnoid space distance (ONSASD) was calculated as ONSD minus OND. Pearson's correlation analysis was used to explore the relationships between ONSD, OND, ONSASD at 3mm, 9mm, 15mm behind the eye ball and CSF-P, whereas Spearman's rho was utilized in the case of non-parametric variables. Stepwise multiple regression analysis was performed between age, mean arterial pressure (MAP), body mass index (BMI) and CSF-P.
Results: :
High positive correlations were found between ONSD, ONSASD at 3mm, 9mm, 15mm behind the eye ball and CSF-P (P<0.001; correlation coefficient>0.650), especially ONSD(P< 0.001;correlation coefficient,0.801) and ONSASD(P< 0.001;correlation coefficient,0.774) at 3mm behind the eye ball. There was a weak and non-significant relationship between OND at 3mm behind the eye ball and CSF-P(P=0.075;correlation coefficient,0.319).Moderate positive correlations were found at 9mm(P< 0.001;correlation coefficient,0.620) and 15mm(P= 0.001;correlation coefficient,0.530). CSF-P was significantly associated with MAP (P < 0.001), BMI (P=0.006) and age (P=0.031).
Conclusions: :
The present results show that ONSD, ONSASD at 3mm behind the eye ball on images obtained using routine sequences, when optic nerve MRI is indicated, may be reliable predictors of CSF-P. CSF-P is significantly associated with MAP, BMI and age.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • neuro-ophthalmology: optic nerve