Longitudinal investigations on the anterograde and retrograde degeneration in the pyramidal tract following pontine infarction with diffusion tensor imaging.
BACKGROUND
Secondary degeneration following supratentorial stroke has been detected by some studies using diffusion tensor imaging (DTI), but the anterograde and retrograde degeneration in pyramidal tract after pontine infarction and its potential clinical significance are not well understood.


METHODS
Fourteen patients with a recent pontine infarct underwent three DTIs at week 1, week 4, and week 12 after onset. Fourteen age- and gender-matched controls underwent DTI once. Mean diffusivity and fractional anisotropy (FA) were measured. Neurological deficit, motor deficit and life independence were assessed with the NIH Stroke Scale, Fugl-Meyer scale and Barthel index, respectively, 2 h before each DTI examination.


RESULTS
FA values at the ipsilateral medulla and the proximal portion of the pyramidal tract, including centrum semiovale, internal capsule and cerebral peduncle, significantly decreased progressively from week 1 to week 12 (p < 0.01). The NIH Stroke Scale decreased; Fugl-Meyer scale and Barthel index increased significantly over the time points (p < 0.01). The absolute values of percent reduction of FA value at the ipsilateral medulla and the proximal portion of pyramidal tract correlated negatively with the absolute values of percent reduction of the NIH Stroke Scale and percent increase of the Fugl-Meyer scale.


CONCLUSIONS
Progressive anterograde and retrograde degeneration in pyramidal tract revealed by DTI may hinder the process of neurological recovery after a pontine infarct. To confirm the clinical significance, future studies with a longer observation period and a larger sample size of patients with more homogeneous pontine infarcts are still needed.
Liang
Zhijian
Z
Department of Neurology and Stroke Centre, Sun Yat-Sen University, Guangzhou, PR China.
Zeng
Jinsheng
J
Zhang
Cuimei
C
Liu
Sirun
S
Ling
Xueying
X
Xu
Anding
A
Ling
Li
L
Wang
Fang
F
Pei
Zhong
Z
D000203:Activities of Daily Living; D000368:Aged; D016022:Case-Control Studies; D002544:Cerebral Infarction / Q000473:pathology* / Q000503:physiopathology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009043:Motor Activity; D011149:Pons / Q000098:blood supply*; D011379:Prognosis; D011712:Pyramidal Tracts / Q000473:pathology* / Q000503:physiopathology; D012183:Retrograde Degeneration / Q000473:pathology* / Q000503:physiopathology; D012720:Severity of Illness Index; D013997:Time Factors; D014855:Wallerian Degeneration / Q000473:pathology* / Q000503:physiopathology