Utility of the Spot Sign on Multiphase CT Angiography for Prediction of Hematoma Expansion in Intracerebral Hemorrhage.

BACKGROUND AND PURPOSE: In intracerebral hemorrhage (ICH), the CTA spot sign is a risk factor for hematoma expansion. While most spot sign studies have used single-phase CTA, multiphase CTA is becoming more common. We aimed to investigate the association between the multiphase CTA spot sign and hematoma expansion in ICH. MATERIALS AND METHODS: We included ICH patients admitted to Karolinska University Hospital from 2019-22 who had non-contrast CT and multiphase CTA on admission, and follow-up CT within 72h. Patients were grouped by the phase in which a spot sign first appeared on mCTA. We examined spot sign numbers, volume, and attenuation in each phase, and their changes between phases. RESULTS: The spot sign was detected in 88/159 patients (55%). Of these, 51 (58%) appeared in phase 1, 28 (32%) in phase 2, and 9 (10%) in phase 3. Hematoma expansion occurred in 25/51 (49%), 13/28 (46%), and 4/9 (44%), respectively, compared to 12/71 (17%) if no spot signs appeared. In patients with hematoma expansion, spots were larger, had higher attenuation, and were more numerous on their first appearance. In subsequent phases, increase in spot numbers, spot volume, and spot attenuation were also associated with hematoma expansion. CONCLUSION: Multiphase CTA uncovered a large group of ICH patients with spot signs appearing only on the second and third phases, at high risk of hematoma expansion. Initial and final phase spot sign characteristics, and their evolution, were associated with hematoma expansion. In comparison to single-phase CTA, using multiphase CTA enabled further identification of patients at high risk of hematoma expansion.