Non-contrast CT findings suggestive of secondary intracerebral haemorrhage

Introduction Most patients with intracerebral hemorrhage (ICH) are initially evaluated using non-contrast CT (NCCT) alone, which may delay or miss diagnoses of secondary causes and limit opportunities for timely targeted intervention. This review aims to identify NCCT findings suggestive of secondary ICH aetiologies. Methods We conducted a systematic literature review. Studies were included if they reported NCCT findings in patients with secondary ICH. We excluded studies focusing exclusively on traumatic ICH or anticoagulation-related ICH. Non-contrast CT findings suggestive of secondary ICH were broadly categorised into 4 domains: (i) intra-parenchymal haemorrhage findings, (ii) extra-parenchymal haemorrhage findings, (iii) non-haemorrhagic findings and (iv) absence of small vessel disease (SVD) findings. Results We identified a range of NCCT findings that mark an increased likelihood of being associated with secondary ICH. Intraparenchymal haemorrhage findings included morphological characteristics or atypical morphologies (eg, “cashew nut sign”, “flame” shape bleeds, calcifications, fluid levels and disproportionate perihaematomal oedema) as well as unusual anatomical locations (eg, multiple bleeds, location outside the deep supratentorial regions, haemorrhages adjacent to typical arterial aneurysmal sites or venous structures). Extra-parenchymal haemorrhage findings included haemorrhage extension into intraventricular, subdural or subarachnoid spaces, and isolated intraventricular haemorrhage. Non-haemorrhagic findings included concomitant ischaemic lesions and venous hyperdensity. The absence of SVD markers also suggested secondary ICH. Conclusion Several NCCT findings can raise suspicion for secondary ICH and may guide early decision-making regarding the need for further imaging beyond NCCT. Recognising these findings is especially valuable in settings with limited access to advanced diagnostics.