Variability of optic nerve sheath diameter in acute ischemic stroke

Abstract

Background: Stroke is the third leading cause of death and the first cause of disability in the world. It holds an important place in hospital admissions and health expenses in the industrialized world. Objective: The aim of the study was to evaluate the relationship between optic nerve sheath diameter and the findings of brain computerized tomography scans and brain diffusion-weighted imaging and investigate the variability of optic nerve sheath diameter measured by ultrasonography in acute ischemic stroke. Methods: Patients who had acute ischemic stroke were included in Group A. Healthy adults were included in Group B as the control group. In addition, according to computerized tomography scans and diffusion-weighted imaging findings, Group A was divided into three subgroups. Patients with normal computerized tomography and diffusion-weighted imaging were included in Group 1, patients with normal computerized tomography and ischemic area on diffusion-weighted imaging were included in Group 2, and patients with ischemic area on computerized tomography and diffusion-weighted imaging were included in Group 3. Results: A total of 100 patients were included in Group A and 100 healthy adults included in Group B. The optic nerve sheath diameter values of Groups A and B were 5.4 ± 0.6 and 4.2 ± 0.4 mm (p < 0.001), respectively. The optic nerve sheath diameter cutoff value for detection of acute ischemic stroke was determined as 4.7 mm. The sensitivity and specificity at this cutoff value were determined as 89% and 90%, respectively. According to computerized tomography scans and diffusion-weighted imaging findings, there were 18 patients in Group 1, 56 patients in Group 2, and 26 patients in Group 3. Time from onset of symptoms to presentation to emergency department was shortest in Group 1 (3.0 ± 1.8 h). The widest optic nerve sheath diameter was calculated in Group 3 (optic nerve sheath diameter: 5.7 ± 0.6 mm). Conclusion: This study demonstrates that the optic nerve sheath diameter increases in acute ischemic stroke and it increases earlier than computerized tomography and diffusion-weighted imaging alteration occur. Therefore, optic nerve sheath diameter can be applied to assist the diagnosis of acute ischemic stroke with other imaging techniques with equivocal/negative results and determination of appropriate treatment, especially in cases with normal computerized tomography scan and diffusion-weighted imaging.