Abstract
Fifty-nine patients with subarachnoid haemorrhage (SAH) were investigated noninvasively to identify those at risk of delayed cerebral ischaemia. Sixteen patients developed ischaemic deficit but there was no clear relationship with computed tomography blood load and distribution. Serial transcranial Doppler ultrasound (TCD) revealed significantly higher middle cerebral artery flow velocities in those with ischaemic deficit but highest values were often not seen until clinical deterioration had occurred. A rapid rise in flow velocity was observed in advance of clinical signs of ischaemia. Regional blood flow on HM-PAO single photon emission computed tomography (SPECT) in 10 patients with this rapid rise showed focal reduced perfusion in 8, 5 progressing to clinical deficit. A further patient developed infarction before SPECT was performed. Sequential TCD offers potential for identification of patients at risk of delayed ischaemic complications of SAH.