A new early and automated MRI-based predictor of motor improvement after stroke.
OBJECTIVE
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 (r(2) = 0.96, p = 0.0002).


CONCLUSIONS
These findings represent a proof of principle that contralesional diffusion MRI measures may provide reliable information for personalized rehabilitation planning after ischemic motor stroke.
Departments of Clinical Neurosciences, Centre Hospitalier Universitaire Vaudois and University of Lausanne, Lausanne, Switzerland. Corr cristina.granziera@chuv.ch
Cristina
C
Granziera
Alessandro
A
Daducci
Djalel E
DE
Meskaldji
Alexis
A
Roche
Philippe
P
Maeder
Patrik
P
Michel
Nouchine
N
Hadjikhani
A Gregory
AG
Sorensen
Richard S
RS
Frackowiak
Jean-Philippe
JP
Thiran
Reto
R
Meuli
Gunnar
G
Krueger
D000328:Adult; D000368:Aged; D057205:Automation, Laboratory; D038524:Diffusion Magnetic Resonance Imaging / Q000639:trends*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology*; D011237:Predictive Value of Tests; D020127:Recovery of Function / Q000502:physiology*; D020521:Stroke / Q000175:diagnosis* / Q000378:metabolism* / Q000503:physiopathology; D013997:Time Factors