The Incremental Diagnostic Value of Delayed Spot Sign for Hematoma Expansion in Spontaneous Intracerebral Hemorrhage: A Paired Meta-Analysis Revealing the Ceiling Effect
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Background The spot sign on first-pass computed tomography angiography (CTA) is an established predictor of hematoma expansion (HE) in spontaneous intracerebral hemorrhage (sICH), yet its sensitivity is limited. While delayed spot sign reportedly has greater ability to predict HE, previous meta-analyses have used unpaired designs, preventing direct quantification of their incremental diagnostic value. Objective To quantify the incremental diagnostic value of delayed spot sign compared to first-pass CTA spot sign for predicting HE via a paired meta-analysis. Methods We systematically searched PubMed, Embase, Web of Science, and Cochrane Library from inception through August 2025 for studies concurrently reporting the diagnostic performance of the spot sign for predicting HE using first-pass CTA and delayed imaging (i.e., delayed-phase CTA, CT perfusion, CT venography, or post-contrast CT). Paired meta-analysis was performed to calculate pooled increments in sensitivity and specificity. Heterogeneity was investigated using meta-regression. Results Ten studies (n = 1101 patients) were included. Compared with the first-pass Spot Sign, delayed Spot Sign significantly increased sensitivity in HE by 21.9% (95% CI: 11.5% to 32.3%, P < 0.001) while reducing specificity by 7.1% (95% CI: -11.6% to -2.6%, P = 0.002). Meta-regression revealed that baseline sensitivity of first-pass CTA accounted for all heterogeneity in the sensitivity increments (adjusted R²=100%), demonstrating a strong ceiling effect where lower baseline sensitivity predicted greater incremental benefit. Conclusion Delayed spot sign provides substantial incremental sensitivity for predicting HE, with its diagnostic utility governed by a clear ceiling effect relative to first-pass CTA performance. These findings support an individualized implementation based on institutional baseline diagnostic capabilities.
