Optic Nerve Sheath Measurements for Noninvasive Monitoring of Malignant Supratentorial Infarcts: A Systematic Review and Meta-Analysis

INTRODUCTION: Early detection of malignant supratentorial infarcts, particularly malignant middle cerebral artery (MCA), is crucial; however, advanced imaging techniques such as MRI and PET are often inaccessible in resource-limited areas. A potential solution for early risk stratification of stroke patients is the optic nerve sheath diameter (ONSD) measured by transorbital ultrasound. The purpose of this study was to evaluate the utility of optic nerve sheath imaging measurements in recognizing malignant infarcts. A meta-analysis on ONSD measurement has been done for acute ischemic stroke patients. METHODS: Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2022 guidelines, a comprehensive search was conducted for studies published between January 2000 and December 2023. A total of six eligible studies were included. These studies were observational studies involving adult patients diagnosed with malignant supratentorial infarcts who underwent ONSD assessment using ultrasonography, computed tomography (CT), or magnetic resonance imaging (MRI). Data extraction and risk of bias assessments were performed independently. A meta-analysis was conducted to pool estimates of mean ONSD measurement, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy using the metamean() and metaprop() functions from the meta R package. RESULTS: Four studies (n = 170) show a high detection rate of 89.01% (95% CI: 82.88-93.13) with low heterogeneity (I² = 21.3%) based on CT findings of malignant middle cerebral artery (MCA) infarction or progression of acute ischemic stroke. Six studies (n = 314) reporting ONSD showed a pooled mean of 5.50 mm (95% CI: 5.24-5.76 mm), though heterogeneity was substantial (I² = 97.0%). Findings show a sensitivity of 89.01%, specificity of 82.94% to 86.63%, PPV of 81.37%, NPV of 92.57%, and overall diagnostic accuracy of 87.82%. An optimal ONSD cutoff value across studies of 4.70 mm to 5.60 mm, with 5.60 mm, demonstrates the highest diagnostic yield (Youden's Index = 0.8947). CONCLUSION: ONSD measurements can be used in determining malignant infarcts.