swirl sign has previously been described in epidural hematomas as areas of low attenuation radiolucency or irregular density the aims of this study were to describe swirl sign in ich study its prevalence study the reliability of the subjective evaluation on computed tomography ct and to explore its prognostic value cts of 203 patients with ich were retrospectively evaluated for the presence of swirl sign association between swirl sign and different clinical and radiological variables was studied inter and intraobserver agreement with regard to the occurrence of swirl sign was substantial к 0 80 and almost perfect к 0 87 respectively swirl sign was found in 30 of the study population 61 of patients with swirl sign were dead at one month compared with 21 of those with no swirl sign p 0 001 only 19 of patients with swirl sign exhibited favorable outcome at three months compared with 53 of those with no swirl sign p 0 001 patients with swirl sign exhibited larger ichs with average ich volume 52 50 ml median 42 ml compared with 15 25 ml median 6 in patients whose ct did not show swirl sign p 0 001 swirl sign was independent predictor of death at one month p 0 03 adjusted odds ratio 2 6 95 ci 1 1 6 and functional outcome at three months p 0 045 adjusted odds ratio 2 6 95 ci 1 02 6 5 as swirl sign showed to be an ominous sign we recommend identification of this sign in cases of ichs.