Should DWI MRI be the primary screening test for stroke?

Patients presenting with focal neurological symptoms may suffer from ischemic stroke, intracerebral hemorrhage, or stroke mimics. Such patients are usually screened with a noncontrast-enhanced computed tomography to rule out hemorrhage and to detect early signs of ischemia. However, the sensitivity of noncontrast-enhanced computed tomography for acute stroke is far inferior to that of diffusion-weighted magnetic resonance imaging and the latter is also very sensitive for identifying acute intracerebral hemorrhage. Most centers perform a magnetic resonance imaging stroke protocol that takes long to accomplish and may therefore delay therapy. Herein, we propose that a short diffusion-weighted imaging-only magnetic resonance imaging protocol can effectively differentiate ischemic stroke from intracerebral hemorrhage and stroke mimics and could therefore be used as the first line screening test for stroke. Adopting such a screening strategy will result in increased diagnostic accuracy and avoidance of unnecessary treatment of stroke mimics with thrombolysis but may come at the increased cost of performing a magnetic resonance imaging at the emergency department. Whether such a strategy will be cost effective or not remains to be tested in future studies.