Stroke welcomes Letters to the Editor and will publish them, if suitable, as space permits. They should not exceed 750 words (including references) and may be subject to editing or abridgment. Please submit letters in duplicate, typed double-spaced. Include a fax number for the corresponding author and a completed copyright transfer agreement form (available online at To the Editor: We congratu...

BACKGROUND Acute ischemic stroke is common and disabling, but there remains a paucity of acute treatment options and available treatment (thrombolysis) is underutilized. Advanced brain imaging, designed to identify viable hypoperfused tissue (penumbra), could target treatment to a wider population. Existing magnetic resonance imaging and computed tomography-based technologies are not widely use...

BACKGROUND AND PURPOSE White matter hyperintensities (WMHs) are associated with progressive age-related cognitive decline and cardiovascular risk factors, but their biological relevance as indicators of generalized white matter injury is unclear. Diffusion tensor imaging provides more sensitive indications of subtle white matter disruption and can therefore clarify whether WMHs represent foci o...

When neuronal activity is suppressed by ischemia of sufficient severity, maintained for a long enough period of time, permanent clinical deficit can be accompanied by radiographic signs of cerebral infarction and histological evidence of ischemic damage. Recent work suggests that this is not an all-ornone event. Between the most densely ischemic region and the more normally perfused brain, an i...

Shadow mapping is a commonly used technique for generating hard shadows in real time. However, existing shadow map based algorithms cannot render full soft shadows penumbras onto arbitrary dynamic geometry by utilizing only consumer level programmable graphics hardware. In this paper we introduce a new fully hardware accelerated penumbra map algorithm which stores additional penumbra informatio...