Hyperacute stroke: ultrafast MR imaging to triage patients prior to therapy

Abstract

Purpose: To test diffusion- and perfusion-weighted MR imaging techniques within the extreme time constraints of stroke evaluation before therapy, and then, with MR imaging, stratify patients into those without ischemia, those with noncortical ischemia, and those with cortical ischemia.

Materials and methods: T2-weighted turbo gradient- and spin-echo images and echo-planar diffusion- and perfusion-weighted images were obtained. Trace diffusion-weighted images and time-to-peak perfusion maps were automatically postprocessed and immediately available for interpretation.

Results: Forty-one patients with acute stroke symptoms underwent imaging within 6 hours of symptom onset; 35 were eligible for the therapy protocol. The mean time from entering the emergency department to beginning MR imaging was 45 minutes; the mean total MR imaging time was less than 15 minutes. Immediate image analysis directly affected individual clinical management. Four patients showed evidence of no infarct; seven, of lacunar infarct; and 24, of acute cortical infarct. Sixteen patients underwent angiography, thirteen had large-vessel occlusion, eleven were treated intraarterially, and in seven, recanalization was achieved.

Conclusion: Echo-planar diffusion- and perfusion-weighted MR imaging for acute stroke is feasible and applicable before therapy decisions. Ultrafast MR imaging permitted immediate triage of 35 patients with symptoms of hyperacute stroke and thus helped avoid the risks from angiography and thrombolytic agents in some or spurred the judicious use of more aggressive intervention in others.