Optimal measurement distance for optic nerve sheath diameter in idiopathic intracranial hypertension via magnetic resonance imaging

Abstract

Objectives: This study aimed to compare the optic nerve sheath diameter (ONSD) values measured using magnetic resonance imaging (MRI) from 3 mm, 7 mm, and 10 mm behind the orbital globe in patients who met the modified Dandy criteria for idiopathic intracranial hypertension (IIH) with those in a healthy control group. Patients and methods: This retrospective study examined 88 optic nerves of 44 participants (33 females, 11 males; mean age: 37.3 +/- 13.6 years; range, 18 to 67 years) between June 2022 and December 2023. Of these, 21 were patients diagnosed with IIH and 23 were healthy controls. T2-weighted propeller sections were used in the measurements. The ONSD was measured from the optic nerves on both the right and left sides of the globe at 3-, 7-, and 10-mm distances. Results: Based on receiver operating characteristic analysis findings, ONSD measurements of 3 mm and 7 mm in the right eye were remarkably significant, and 10-mm ONSD measurements were moderately significant in estimating IIH, with area under the curve (AUC) values of 0.889, 0.813 and 0.719, respectively. For the left eye, the 3-mm ONSD measurements displayed substantial results at a high level. In comparison, the 7-and 10-mm ONSD measurements yielded significant results at a moderate level when predicting IIH, with AUC values of 0.816, 0.794, and 0.738, respectively). Conclusion: Optic nerve sheath diameter measurements were more sensitive to the disease in proximal segments. In the MRI assessment of IIH patients, measurements should predominantly be taken from proximal segments.