Optic nerve sonographic parameters in idiopathic intracranial hypertension, case-control study

The most common diagnostic error of IIH is inaccurate funduscopic examination. Moreover, IIH could be diagnosed without papilledema. Trans orbital sonography could be used as a non-invasive and cheap tool for discovering increased ICP (intracranial Pressure). Aim of our study was discovering the changes in ultra-sonographic indices and which one could predict the increased ICP. Sixty-eight patients were diagnosed as definite IIH and 68 healthy volunteers are included in the study who had the same sex and age. ONSD, peak systolic velocity (PSV), end diastolic velocity (EDV), and resistance index (RI) were estimated by transorbital color Doppler. Multivariate linear regression was used to discover the predictors of increased ICP. ROC curve was plotted for the predictor. A statistically significant difference was found between IIH patients and controls regarding ONSD, EDV and RI. Multivariate linear regression revealed that ONSD is the only predictor of increased CSP pressure. Its cut-off value indicating high ICP was 5.7 mm on Rt and Lt eye (AUC: 0.916; 95% confidence interval 0.867-0.965; p < 0.001; 90% sensitivity, 80% specificity at Rt eye. AUC: 0.902; 95% confidence interval 0.845-0.958; p < 0.001; 91% sensitivity, 80% specificity at Lt eye).