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Charlotte Rosso, Olivier Colliot, Romain Valabrègue, Sophie Crozier, Didier Dormont, Stéphane Lehéricy and Yves Samson. Tissue at risk in the deep middle cerebral artery territory is critical to stroke outcome. Neuroradiology Volume 53, Number 10, 763-771, DOI: 10.1007/s00234-011-0916-5

We have often seen that patients with predominant cortical ischemia do well over time however, the ones with large deep white matter infarcts have poor outcomes. A growing body of evidence has been accumulating the same. In this recent article, the authors have used voxel based ADC mapping and diffusion tensor imaging to establish this fact.

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Abstract

Introduction 

The clinical efficacy of thrombolysis in stroke patients is explained by the increased rate of recanalization, which limits infarct growth. However, the efficacy could also be explained by the protection of specific sites of the brain. Here, we investigate where is this outcome-related tissue at risk using voxel-based analysis.

Methods 

We included 68 acute stroke patients with middle cerebral artery (MCA) occlusion on the admission MRI performed within 6 h of symptoms onset (H6) and 16 controls. MCA recanalization was assessed using the magnetic resonance angiography performed at day 1 (D1). Apparent diffusion coefficient (ADC) changes were analyzed using a voxel-based method between patients vs. controls group at admission (H6) in non-recanalized vs. recanalized and in 3-month poor vs. good outcome patients at D1.

Results 

Complete or partial MCA recanalization was observed in 52 of 68 patients. Good outcome at 3 months occurred in 40 patients (59%). In non-recanalized patients, ADC was decreased in the deep MCA and watershed arterial territory (the lenticular nucleus, internal capsule, and the overlying periventricular white matter). This decrease was not observed in recanalized patients at D1 or patients at H6. Fiber tracking suggested that the area is crossed by the cortico-spinal, cerebellar, and intra-hemispheric association tracts. Finally, this area almost co-localized with the area associated with poor outcome.

Conclusions 

A clinically relevant area of tissue at risk may occur in patients with MCA infarcts at the level of deep white matter fiber tracts. These findings suggest that neuroprotection research should be refocused on white matter.

Keywords  Stroke – Recanalization – Outcome – MRI – DWI