Focal Wallerian degeneration of the corpus callosum in large middle cerebral artery stroke: serial diffusion tensor imaging.
OBJECTIVE
To detect lesion-related focal Wallerian degeneration (WD) changes in different segments of the corpus callosum (CC) in patients with large middle cerebral arterial (MCA) territory stroke using diffusion tensor imaging (DTI).


METHODS
Eight patients underwent DTI scans at three different time points: six to eight weeks, 10-12 weeks, and beyond six months of stroke onset. Eight healthy age-matched controls were also scanned using the same protocol at three different time points. Region-of-interest (ROI) analysis was performed on seven segments of the CC to determine the fractional anisotropy (FA), mean diffusivity (MD), and corresponding callosal cross-sectional areas.


RESULTS
On repeated-measures analysis of variance (ANOVA), a significant reduction in the FA values was observed from the first to the third study compared to controls, reflecting temporal degeneration in the rostrum, genu, rostral body, anterior midbody, and splenium of the CC. However, a significant temporal elevation in MD values was observed in only the rostral body and anterior midbody of the CC. This was associated with a significant region-specific reduction in the cross-sectional areas at time points beyond six months, and appears to be consistent with the loss of callosal structural components due to interruption of the cortico-callosal fibers secondary to WD.


CONCLUSIONS
These results indicate that cortico-callosal topographical changes exhibit a significant temporal decline in observed FA values that is suggestive of cortico-callosal WD in patients with large MCA territory stroke.
Gupta
Rakesh K
RK
Department of Radiodiagnosis, King George's Medical University, Lucknow, India.
Saksena
Sona
S
Hasan
Khader M
KM
Agarwal
Atul
A
Haris
Mohammad
M
Pandey
Chandra M
CM
Narayana
Ponnada A
PA
D000328:Adult; D016880:Anisotropy; D001921:Brain / Q000473:pathology; D003337:Corpus Callosum / Q000473:pathology*; D004058:Diffusion; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D020244:Infarction, Middle Cerebral Artery / Q000175:diagnosis* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D020521:Stroke; D013997:Time Factors; D014855:Wallerian Degeneration / Q000175:diagnosis* / Q000473:pathology*