Advanced imaging such as MRI or CT perfusion does not appear to improve thrombectomy outcomes at 90 days in patients presenting late with ischaemic stroke, a study shows.

The findings support the use of noncontrast CT plus angiography (NCCT) to assess a patient for thrombectomy, the international researchers say.

In the CT for Late Endovascular Reperfusion (CLEAR) study, results for a cohort of 1600 patients from 15 hospitals in five countries across North America and Europe were analysed retrospectively.

All had undergone mechanical thrombectomy in the “extended time window” of between six and 24 hours from when they were last seen well.