Seby John, MD

Li L, Simoni M, Küker W, Schulz UG, Christie S, Wilcock GK, et al. Population-Based Case–Control Study of White Matter Changes on BrainImaging in Transient Ischemic Attack and Ischemic Stroke. Stroke. 2013

Scrolling through MRIs, we often notice white matter changes (WMC), and radiology reports such as “nonspecific T2/FLAIR hyperintensities in the periventricular white matter, most likely secondary to chronic microvascular ischemic change” are all too familiar.  Previous studies have reported an association between WMC and incident/recurrent ischemic stroke. However, most studies found this association only with small vessel stroke (SVS).

Peter Rothwell’s group sought to investigate presence of WMC per stroke subtype. WMC in patients with first-ever TIA or ischemic stroke (n=1601) were compared to controls without history of ischemic events (n=313). Presence and severity of WMC on CT and/or MRI were graded using the modified Blennow/Fazekas and ARWMC scales respectively. After adjusting for age, sex, diabetes and hypertension, the authors found that moderate-to-severe WMC were more frequent in SVS, as compared to strokes from large vessel, cardioembolic or indeterminate etiology. This association was strongest in younger patients, and was lost at older ages.

Apart from research implications regarding the mechanisms explaining WMC and SVS, this study gives us useful information for clinical practice. Consider a non-stroke neurologist who sees WMC on brain imaging done for non-vascular complaints. In the correct clinical context, they can be reassured that it is likely from small vessel disease and studying the carotids or the heart may not be indicated. Rather, emphasis on optimal risk factor management would be more important. If seen on CT, perhaps this may suffice since CT and MRI-based comparisons were consistent in this study. I think this applies less in stroke clinics, since patients will more than likely need a thorough etiological evaluation. With sweeping reimbursement changes expected from the Affordable Care Act, this may provide some help with stratification of test ordering.