Ultrasonography of optic nerve sheath diameter for detection of raised intracranial pressure: a systematic review and meta-analysis

To evaluate the diagnostic accuracy of ultrasonography of optic nerve sheath diameter (ONSD) for assessment of intracranial hypertension. Systematic review without language restriction based on electronic databases, with manual review of literature and conference proceedings until July 2010. Studies were eligible if they compared ultrasonography of ONSD with intracranial pressure (ICP) monitoring. Data were extracted independently by three authors. Random-effects meta-analysis and meta-regression were performed. Six studies including 231 patients were reviewed. No significant heterogeneity was detected for sensitivity, specificity, positive and negative likelihood ratios or diagnostic odds ratio. For detection of raised intracranial pressure, pooled sensitivity was 0.90 [95% confidence interval (CI) 0.80-0.95; p for heterogeneity, p (het) = 0.09], pooled specificity was 0.85 (95% CI 0.73-0.93, p (het) = 0.13), and the pooled diagnostic odds ratio was 51 (95% CI 22-121). The area under the summary receiver-operating characteristic (SROC) curve was 0.94 (95% CI 0.91-0.96). Ultrasonography of ONSD shows a good level of diagnostic accuracy for detecting intracranial hypertension. In clinical decision-making, this technique may help physicians decide to transfer patients to specialized centers or to place an invasive device when specific recommendations for this placement do not exist.