Swirls and spots: relationship between qualitative and quantitative hematoma heterogeneity, hematoma expansion, and the spot sign

Background: Acute intracerebral hemorrhage (ICH) heterogeneity on NCCT, characterized by qualitative and quantitative methods, is predictive of hematoma expansion and mortality however association with the spot sign is not well-described. We sought to validate and determine the association between qualitative and quantitative hematoma heterogeneity with expansion and the spot sign, respectively. Methods: We retrospectively studied 71 ICH patients presenting <24 h post-ictus with baseline NCCT, CTA and 24-hour follow-up CT available. Baseline NCCT was assessed qualitatively for presence of swirl sign or hematoma heterogeneity by two independent readers blinded to CTA findings and quantitatively using CT densitometry (CTD). Associations with 24-hour hematoma expansion ≥6 ml or ≥33 % and spot sign were assessed using logistic regression and diagnostic performance was assessed. Association between qualitative and quantitative densitometry parameters was also examined. Results: Swirl sign and quantitative CTD standard deviation were independently associated with expansion on multivariable analysis (p = 0.037 and p = 0.032, respectively). Swirl sign and hematoma heterogeneity were predictive of CTA spot sign (p = 0.020 and p = 0.035, respectively) while CTD standard deviation demonstrated only trend univariate association. CTD parameters were not significantly associated with swirl sign while only CTD skewness was associated with hematoma heterogeneity. Agreement for swirl sign and hematoma heterogeneity identification was nearly perfect (κ = 0.81) and substantial (κ = 0.79) respectively. Conclusion: NCCT qualitative parameters predict hematoma expansion and CTA spot sign presence. Quantitative markers independently predict hematoma expansion but not CTA spot sign presence.