Utility of Optic Nerve Sheath Diameter Measured by Ultrasonography for the Detection of Increased Intracranial Pressure in Adults

ABSTRACT

PURPOSE: To evaluate the utility of ONSD (optic nerve sheath diameter) measured by US (ultrasonography) in detecting the presence of increased intracranial pressure. METHODS: This prospective study was done from October, 2007, to March, 2008. Patients who were 18 years or younger, had a recent ocular or periocular disease, had an abnormal Q test (Queckenstedtis test), or were uncooperative were excluded. The patients were divided into group A (increased CSF pressure group > or =200 mmCSF) and group B (normal CSF pressure <200 mmCSF). The ONSDs were measured using a 3~12 MHz ultrasonographic probe on the closed eyelids. We analyzed the correlation between the CSF (cerebrospinal fluid) pressure and the ONSD. RESULTS: There were 21 patients in group A and 70 patients in group B. The mean for binocular ONSDs in group A was 5.1+/-0.6 mm and 4.5+/-0.4 mm in group B (plt;0.01). The CSF pressure correlated with the ONSD (Correlation Coefficient=0.54) (plt;0.01). In the ROC curve (Receiver operating characteristic curve) for ONSD to distinguish group A from B, the AUC was 0.8 (95% confidence interval 0.7~0.9) with a sensitivity of 81.0%, and a specificity of 75.7% when the cut off value was set at 4.7 mm. CONCLUSION: The ONSD was related to the CSF pressure, with a difference in the ONSD between group A and group B. The ONSD, as measured by US, can be used to detect the presence of high ICP.