Co-localization of NCCT hypodensity and CTA spot sign predicts substantial intracerebral hematoma expansion: The Black-&-White sign

Background: Existing radiological markers of hematoma expansion (HE) show modest predictive accuracy. We aim to investigate a novel radiological marker that co-localizes findings from non-contrast CT (NCCT) and CT angiography (CTA) to predict HE. Methods: Consecutive acute intracerebral hemorrhage patients admitted at Foothills Medical Centre in Calgary, Canada, were included. The Black-&-White sign was defined as any visually identified spot sign on CTA co-localized with a hypodensity sign on the corresponding NCCT. The primary outcome was hematoma expansion (>= 6 mL or >= 33%). Secondary outcomes included absolute (<3, 3-6, 6-12, >= 12 mL) and relative (0%, <25%, 25%-50%, 50%-75%, or >75%) hematoma growth scales. Results: Two-hundred patients were included, with 50 (25%) experiencing HE. Forty-four (22%) showed the spot sign, 69 (34.5%) the hypodensity sign, and 14 (7%) co-localized both as the Black-&-White sign. Those with the Black-&-White sign had higher proportions of HE (100% vs 19.4%, p < 0.001), greater absolute hematoma growth (23.37 mL (IQR = 15.41-30.27) vs 0 mL (IQR = 0-2.39), p < 0.001) and relative hematoma growth (120% (IQR = 49-192) vs 0% (0-15%), p < 0.001). The Black-&-White sign had a specificity of 100% (95%CI = 97.6%-100%), a positive predictive value of 100% (95%CI = 76.8%-100%), and an overall accuracy of 82% (95%CI = 76%-87.1%). Among the 14 patients with the Black-&-White sign, 13 showed an absolute hematoma growth >= 12 mL, and 10 experienced a HE exceeding 75% of the initial volume. The inter-rater agreement was excellent (kappa coefficient = 0.84). Conclusion: The Black-&-White sign is a robust predictor of hematoma expansion occurrence and severity, yet further validation is needed to confirm these compelling findings.