Abstract

Assessment of the Intra- and Inter-Observer Reliabilities of Ultrasonographically Measured Optic Nerve Sheath Diameters in Normal Adults

Author(s): Li-juan Wang, Li-min Chen, Ying Chen, Yang-yang Zhou, Jie Zhang, Ying-qi Xing

Abstract

Objective: Previous studies have used determined the optic nerve sheath diameter (ONSD) ultrasonographically as a measure of elevated intracranial pressure. The present study was conducted to evaluate the intra- and inter-observer reliability, and therefore the clinical feasibility, of this method.

Methods:Two observers independently measured the ONSD in the sagittal and transversal planes in 300 healthy adults. Each observer performed the measurements twice, and the measured values were used to calculate the intra- and inter-observer reliabilities. Intra- and inter-observer reliability was analyzed using Cronbach’s alpha, Pearson’s correlation coefficient and a Bland–Altman analysis, respectively.

Results: The mean ONSD was 3.59 ± 0.28 mm, with a range of 2.96-4.36 mm, and the Cronbach’s alpha values were 0.992 and 0.983 for observers 1 and 2, respectively. Pearson’s correlation coefficient between the observers was 0.89, and a Bland–Altman analysis yielded a mean difference of 0.04 ± 0.16 mm between measurements.

Conclusion: The ultrasonographic measurement of ONSD is an easily learned and reproducible technique with high intra- and inter-observer reliability. Our results provide a basis for the future clinical application of this technique.