Conundra of the Penumbra and Acute Stroke Imaging

Abstract

Multimodal imaging of the brain and vasculature during the hyperacute phase of ischemic stroke is perhaps the “mother of all controversies” in stroke's modern era. Opposing views are firmly held and often cleverly defended, as is the case with Drs Lyden and Parsons. Let us highlight the facts: 1 time is brain, every minute counts; and 2 the significance of the ischemic penumbra as a potentially salvageable tissue, if reperfusion is successfully restored in a timely fashion, is undisputed. Now, let us address the following questions regarding the potential benefit (or lack of it) from the additional information gained by MRI with diffusion-weighted imaging, perfusion MRI or CT, or CT angiography, MR angiography, or transcranial Doppler. Is there an added benefit from knowing the vascular anatomy of the patient with stroke who presents within the approved time window for intravenous tissue-type plasminogen activator (tPA)? Knowing the vascular lesion before treatment is certainly helpful but is unlikely to change the management strategy, regardless of the location of the arterial occlusion, during the first 3 to 4.5 hours of stroke onset because there is no evidence to support endovascular intervention as a first-line therapy during this time window, especially when considering the time it takes to get the patient …