Russell Mitesh Cerejo, MD

Makin SDJ, Doubal FN, Dennis MS, and Wardlaw JM. Clinically Confirmed Stroke With Negative Diffusion-Weighted Imaging Magnetic Resonance Imaging: Longitudinal Study of Clinical Outcomes, Stroke Recurrence, and Systematic Review. Stroke. 2015

The authors, in their paper titled “Clinically-confirmed stroke with negative DWI MRI. Long term clinical outcomes, stroke recurrence and systematic review”, raise an important question, if a patient with clinical symptoms of stroke has a negative DWI – MRI does that patient have a better prognosis? To answer this question they performed a prospective observational study over 2 years of patients presenting to a single center with acute non-disabling strokes. They collected initial clinical and imaging characteristics and followed these patients for a year. 

 They enrolled 264 patients of whom nearly one-third had no acute lesion on MRI. DWI-positive patients were more likely to have carotid stenosis, Atrial arrhythmias, higher NIHSS, more White matter hyper intensities and cortical stroke. DWI-negative patients were more likely to have ischemic heart disease or a previous stroke, and be scanned later. After adjustment for age and sex, any embolic source and time to scanning were no longer associated with lesion presence. Of the 198 patients that follow up with a 1-year scan, the patients without an acute ischemic index MRI lesion were just as likely to have persistent symptoms, cognitive impairment, stroke-related disability (mRS≥2), or recurrent stroke/TIA as those who had a DWI-positive index lesion.

They also performed a meta-analysis of prior studies looking at non-disabling strokes and MRI findings and found a similar number of DWI negative strokes in those patients. The study suggests that even in DWI negative patients presenting with acute stroke symptoms, secondary prevention must be pursued as aggressively as in those with DWI-positive stokes.