Peri-infarct reorganization in a patient with corona radiata infarct: a combined study of functional MRI and diffusion tensor image tractography.
OBJECTIVE
We investigated the motor recovery mechanism of a stroke patient using functional MRI (fMRI) and diffusion tensor image tractography (DTT).


METHODS
A 60 year-old woman with right corona radiata infarct presented with complete paralysis of the left upper extremity. The motor function of the affected upper extremity recovered slowly for 6 months to a point of nearly normal function. The motor function of the patient was evaluated by fMRI and DTT at 6 months from the onset. FMRI was performed at 1.5 T with timed hand grasp-release movements. DTT was performed using 1.5 T with a synergy-L Sensitivity Encoding head coil. Three dimensional reconstructions of the fiber tracts were obtained with FA < 0.3, angle > 45 degrees as termination criteria.


RESULTS
The contralateral primary sensorimotor cortex (SM1) was activated during both affected (left) and unaffected hand movements. DTT showed that the tracts originated from either SM1; the tracts then descended along the known pathway of the corticospinal tract, with the exception that the tract of the affected (right) hemisphere descended along the posterior portion of the infarcted corona radiata.


CONCLUSIONS
It seems that the motor function of the affected upper extremity was reorganized to the posterior portion of the infarcted corona radiata. This finding may reflect functional reorganization of the motor pathway following corticospinal tract damage. This appears to be one motor recovery mechanism of subcortical infarct.
Jang
Sung Ho
SH
Department of Physical Medicine and Rehabilitation, School of Medicine, Yeungnam University, Republic of Korea. strokerehab@hanmail.net
Ahn
Sang Ho
SH
Ha
Jung Sang
JS
Lee
Se Jin
SJ
Lee
Jun
J
Ahn
Young Hwan
YH
D000818:Animals; D020520:Brain Infarction / Q000473:pathology* / Q000503:physiopathology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000098:blood supply / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D011712:Pyramidal Tracts / Q000098:blood supply / Q000473:pathology / Q000503:physiopathology