CT swirl sign in primary intracerebral haemorrhage and association with haematoma expansion

Abstract

Background & Objective: Haematoma expansion is an important predictor of poor clinical outcomes for primary acute intracerebral haemorrhage (ICH). Swirl sign is described as an area which is hypodense or isodense surrounded by hyperdense acute haemorrhage. This study aimed to describe swirl sign in ICH, its prevalence and to determine if the presence of swirl sign, swirl volume and the ratio of swirl to initial haematoma volume are associated with haematoma expansion and to predict clinical outcome in ICH.

Methods: One hundred and sixty-three patients who had spontaneous ICH with initial (CT1) and repeat CT (CT2) within 96 hours were included. Presence of swirl sign, its volume and the ratio of swirl volume over haematoma volume in initial and repeat CT were calculated using semi auto-segmentation from ‘ITK snap’. Statistical analysis using Spearman’s correlation coefficient and chi-square test were done to assess the relationship between the data parameters with haematoma expansion as well as functional outcome and mortality at 1 month.

Results: Chi-square test showed a significant association between the presence of swirl sign with the haematoma expansion (p < 0.001) and mRS score at 1 month (p < 0.05). Spearman correlation showed a significant moderate correlation between swirl sign and volume of haematoma expansion (r = 0.518, p < 0.001). Ratio of swirl volume/initial haematoma volume demonstrated low correlation but however significant with haematoma expansion (r=0.28 p < 0.05).

Conclusion: Swirl sign, its volume as well as the ratio of swirl volume over initial haematoma are associated with haematoma expansion. It can be used as a predictor of mortality and functional outcome at one month.