The Significance of Contrast Density of the Computed Tomography-Angiographic Spot Sign and its Correlation with Hematoma Expansion

Abstract Background and Purpose The computed tomography angiographic (CTA) spot sign has been shown to predict hematoma expansion in patients with intracranial hemorrhage (ICH), but the significance of the spot sign density (SSD) and the spot sign ratio (SSR) has not yet been explored. Methods Using the institutional Neurocritical care and Stroke registry, we retrospectively reviewed patients with ICH from January-2013 to June-2017. We selected patients who had baseline CT-head (CTH), CTA with positive-spot sign within 6 hours of last known well and at least one follow-up CTH within 24 hours. Baseline demographics and variables known to affect hematoma-volume were collected. Hematoma-volumes and SSR were calculated using computer-assisted 3D-volumetric measurement and the average of the surrounding hematoma density divided by the SSD, respectively. The 2-sample t test and the area-under-the-curve (receiver operating characteristic) were used to detect the association between hematoma expansion and outcome at discharge. Results A total of 320 patients were reviewed; 22 met the inclusion criteria. Significant hematoma expansion (volume expansion ≥12.5 cc or ≥33% compared to baseline) was noted in 14 (64%) subjects. SSD was significantly higher in subjects with hematoma expansion (216 ± 66) than those without (155 ± 52, P = .036). With a cut-off SSD of ≥150 HU, we had sensitivity of 86% and specificity of 75%. For SSR, lower ratios suggested a trend toward hematoma expansion, although it was not statistically significant ( P = .12). There was no significant correlation between SSD or SSR and modified ranking scale at discharge and after 3-6 months. Conclusion SSD might be a good predictor of hematoma growth. Although SSR showed a trend toward expansion, results were not statistically significant.