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Abstract
Objectives: In this study, we investigated the structural plasticity of the contralesional motor network in ischemic stroke patients using diffusion magnetic resonance imaging (MRI) and explored a model that combines a MRI-based metric of contralesional network integrity and clinical data to predict functional outcome at 6 months after stroke.
Methods: MRI and clinical examinations were performed in 12 patients in the acute phase, at 1 and 6 months after stroke. Twelve age- and gender-matched controls underwent 2 MRIs 1 month apart. Structural remodeling after stroke was assessed using diffusion MRI with an automated measurement of generalized fractional anisotropy (GFA), which was calculated along connections between contralesional cortical motor areas. The predictive model of poststroke functional outcome was computed using a linear regression of acute GFA measures and the clinical assessment.
Results: GFA changes in the contralesional motor tracts were found in all patients and differed significantly from controls (0.001 ≤ p < 0.05). GFA changes in intrahemispheric and interhemispheric motor tracts correlated with age (p ≤ 0.01); those in intrahemispheric motor tracts correlated strongly with clinical scores and stroke sizes (p ≤ 0.001). GFA measured in the acute phase together with a routine motor score and age were a strong predictor of motor outcome at 6 months (r2 = 0.96, p = 0.0002).
Conclusion: These findings represent a proof of principle that contralesional diffusion MRI measures may provide reliable information for personalized rehabilitation planning after ischemic motor stroke. Neurology® 2012;79:39–46
GLOSSARY
- Cd=
- Cook distance;
- DSI=
- diffusion spectrum imaging;
- DTI=
- diffusion tensor imaging;
- FA=
- fractional anisotropy;
- FIM=
- Functional Independence Measure;
- FOV=
- field of view;
- GFA=
- generalized fractional anisotropy;
- GLM=
- general linear model;
- M1=
- primary motor area;
- MANOVA=
- multivariate analysis of variance;
- MPRAGE=
- magnetization-prepared rapid gradient echo;
- mRS=
- modified Rankin Scale;
- NIHSS=
- NIH Stroke Scale;
- PMd=
- dorsal premotor area;
- PMv=
- ventral premotor area;
- TE=
- echo time;
- tp=
- time point;
- TR=
- repetition time
Footnotes
Study funding: Supported by Centre d'Imagerie BioMédicale of the University of Lausanne, the Swiss Federal Institute of Technology Lausanne, the University of Genève, the Centre Hospitalier Universitaire Vaudois, the Hôpitaux Universitaires de Genève, the Leenaards, the Jeantet and the Stoicescu Foundations, and the Swiss National Science Foundation Grant PZ00P3_131914/1. The funding source had no role in study design, in the collection, analysis, and interpretation of data, in the writing of the report, or in the decision to submit the article for publication.
Supplemental data at www.neurology.org
- Received December 13, 2011.
- Accepted February 17, 2012.
- Copyright © 2012 by AAN Enterprises, Inc.
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