Diagnostic Accuracy of Transcranial Doppler and Electroencephalogram for Delayed Cerebral Ischemia Following Aneurysmal Subarachnoid Hemorrhage: A Systematic Review and Meta-Analysis

This review was done to assess the diagnostic accuracy of transcranial Doppler (TCD) or electroencephalogram (EEG) accuracy for delayed cerebral ischemia (DCI) in adults with aneurysmal subarachnoid hemorrhage. MEDLINE, Embase, Cochrane CENTRAL, Scopus, and Web of Science were searched from inception to April 2025. Two reviewers independently screened studies, extracted 2 × 2 diagnostic data, and assessed the risk of bias using QUADAS-2. Pooled sensitivity, specificity, positive and negative likelihood ratios (LR⁺, LR^-), diagnostic odds ratios (DOR), and area under the hierarchical summary receiver-operating characteristic curve (AUROC) were estimated via bivariate random-effects models. Fifty-two studies (38 TCD; 14 EEG), encompassing 1278 DCI-positive and 3033 DCI-negative assessments, met inclusion. For TCD, pooled sensitivity was 0.79 (95% CI: 0.71-0.85) and specificity 0.82 (0.75-0.87), with LR⁺ 4.3 (3.1-6.1), LR^- 0.26 (0.19-0.36), DOR 17 (9-31), and AUROC 0.87 (0.84-0.90). EEG yielded sensitivity 0.92 (0.83-0.97) and specificity 0.70 (0.58-0.80), with LR⁺ 3.1 (2.1-4.6), LR^- 0.11 (0.05-0.27), DOR 27 (9-83), and AUROC 0.89 (0.86-0.91). Deek's tests showed no publication bias. TCD and EEG both demonstrate strong diagnostic accuracy for DCI after aneurysmal subarachnoid hemorrhage. EEG offers superior sensitivity and rule-out value, while TCD provides balanced rule-in and rule-out performance.