OBJECTIVE The spot sign is related with the risk of hematoma expansion in spontaneous intracerebral hemorrhage (ICH). However, not all spot sign positive patients undergo hematoma expansion. Thus, the present study investigates the specific factors enhancing the spot sign positivity in predicting hematoma expansion. METHODS We retrospectively studied 316 consecutive patients who presented between March 2009 to March 2011 with primary ICH and whose initial computed tomography brain angiography (CTA) was performed at our Emergency Department. Of these patients, 47 primary ICH patients presented spot signs in their CTA. We classified these 47 patients into two groups based on the presence of hematoma expansion then analyzed them with the following factors : gender, age, initial systolic blood pressure, history of anti-platelet therapy, volume and location of hematoma, time interval from symptom onset to initial CTA, spot sign number, axial dimension, and Hounsfield Unit (HU) of spot signs. RESULTS Of the 47 spot sign positive patients, hematoma expansion occurred in 26 patients (55.3%) while the remaining 21 (44.7%) showed no expansion. The time intervals from symptom onset to initial CTA were 2.42±1.24 hours and 3.69±2.57 hours for expansion and no expansion, respectively (p=0.031). The HU of spot signs were 192.12±45.97 and 151.10±25.14 for expansion and no expansion, respectively (p=0.001). CONCLUSIONS The conditions of shorter time from symptom onset to initial CTA and higher HU of spot signs are the emphasizing factors for predicting hematoma expansion in spot sign positive patients.