Diagnostic value of swirl sign on noncontrast computed tomography and spot sign on computed tomographic angiography to predict intracranial hemorrhage expansion

Objective: Intracranial hemorrhage (ICH) expansion is a predictor of poor clinical outcome. ICH expansion can be predicted with a swirl sign on noncontrast computed tomography (NCCT) and/or a spot sign on computed tomographic angiography (CTA). In this study, we aimed to evaluate the diagnostic value of a swirl sign and a spot sign in identifying hematoma expansion. Patients and methods: Patients with spontaneous ICH between January 2013 and August 2018 who underwent an initial NCCT and CTA, and a subsequent NCCT at a single center were retrospectively identified. Two experienced neuroradiologists reviewed all images for swirl sign and spot sign presence using a 4-point scale for receiver-operative characteristic analysis. ICH expansion was defined as volume growth of >33% or >6 mL. Results: A total of 227 patients, including 54 with ICH expansion, qualified for analysis. For both observers, the area under the curve (AUC) of spot sign was significantly higher than that of swirl sign (observer 1: 0.748 vs. 0.577, p = .002; observer 2: 0.749 vs. 0.589, p = .004). The sensitivities of ICH expansion in patients with a spot sign was significantly higher than patients with a swirl sign (observer 1: 54.1% vs. 28.0%, p = .002; observer 2: 56.9% vs. 30.3%, p = .002). Patients with a spot sign had the highest risk of ICH expansion (odds ratio: observer 1 = 8.14, observer 2 = 9.30, p < 0.001). Conclusions: A spot sign on CTA was identified and associated with ICH expansion. A swirl sign on NCCT had a relatively low sensitivity and AUC, and will not be able to replace spot sign on CTA.