Sonographic diameter of optic nerve sheath in differentiation of ischemic and hemorrhagic strokes; a diagnostic accuracy study

Abstract

IntroductionDifferentiating between ischemic and hemorrhagic types is of special importance in the treatment process of patients with stroke. The present study was designed with the aim of evaluating the diagnostic accuracy of ultrasonographic optic nerve sheath diameter (ONSD) in differentiation of ischemic from hemorrhagic stroke. MethodsThe present research is a diagnostic accuracy study on patients with stroke presenting to emergency department during 1 year. Ultrasonographic diameter of optic nerve sheath of both eyes was measured for all the patients and its sensitivity, specificity, positive and negative predictive values and positive and negative likelihood ratios in differentiating ischemic stroke from hemorrhagic type were calculated considering CT scan findings as the gold standard. Results80 patients with stroke (40 hemorrhagic and 40 ischemic) were studied. Mean age of the patients was 65.0 ± 13.1 years (57.5% male). Mean ONSD was 5.5 ± 0.4 mm in the ischemic group and 6.1 ± 0.7 mm in the hemorrhagic group (p < 0.0001). Area under the curve of ONSD in differentiation of hemorrhagic and ischemic stroke was 0.75 (95% CI: 0.64–0.86). In 5.5 mm cut-off point, sensitivity and specificity of ONSD in identifying the type of stroke were 75.0% (95% CI: 58.5–86.8) and 52.5% (95% CI: 36.3–68.2), respectively. These values were 57.5% (95% CI: 41.0–68.2) and 90.0% (95% CI: 75.4–96.7), respectively, in the 6 mm cut-off point. ConclusionFindings of the present study showed that ultrasonographic diameter of optic nerve sheath has moderate accuracy in differentiation of hemorrhagic and ischemic stroke.