Brain scan within 24 hours of mild stroke predicts risk of further stroke, study shows
BMJ 2014; 349 doi: http://dx.doi.org/10.1136/bmj.g7519 (Published 08 December 2014) Cite this as: BMJ 2014;349:g7519
A computed tomography (CT) scan of the brain within 24 hours of a transient ischaemic attack (TIA) or non-disabling stroke accurately predicts the risk of further stroke within 90 days and provides useful information to guide treatment decisions, a prospective study has found.
Patients who have a TIA generally have their risk of a stroke assessed using a simple scoring system based on age, blood pressure, diabetes status, and TIA symptoms. But the growing use of brain imaging has raised the question of whether it can further improve predictions of subsequent stroke.
Researchers prospectively enrolled 2028 patients with TIA or non-disabling stroke who had undergone CT scanning after being admitted to one of eight Canadian emergency departments from October 2006 to April 2010.1 The scan results showed that 40% (814) of the patients had ischaemic changes on CT, and follow-up showed that this was associated with an increased risk of stroke in the next 90 days.
Patients whose CT scan showed ischaemia, indicating newly damaged brain tissue, had more than twice the risk of subsequent stroke within 90 days compared with patients without ischaemic changes (odds ratio 2.61 (95% confidence interval 1.22 to 5.57)).
This risk increased when the brain CT scan showed more severe damage. It was five times higher in patients whose scans showed acute and chronic ischaemia (5.35 (1.71 to 16.70)) and eight times higher in those who also had narrowing of small blood vessels (8.04 (1.52 to 42.63)).
“All patients should get a CT scan of their brain after a TIA or non-disabling stroke,” said Jeffrey Perry, senior author and associate professor of emergency medicine at the University of Ottawa in Canada. “Images can help healthcare professionals identify patterns of damage associated with different levels of risk for a subsequent stroke or help predict when symptoms may get worse.”
He said that treatment should be more aggressive in patients with TIA or non-disabling stroke who have acute ischaemia on brain CT scan, especially if they also have chronic ischaemia or narrowing of blood vessels.
Cite this as: BMJ 2014;349:g7519
Perry JJ, Sivilotti M, Sutherland J, Worster A, Émond M, Jin A, et al. CT identifies patients at high risk for stroke after TIA/non-disabling stroke: a prospective multi-center cohort study. Stroke2014; published online 4 Dec; doi:10.1161/STROKEAHA.114.006768.