Very early demonstration of secondary pyramidal tract degeneration by computed tomography.
BACKGROUND
While magnetic resonance imaging has revealed progressive changes in the pyramidal tract in accordance with histopathologic stages of wallerian degeneration secondary to a supratentorial lesion, computed tomography (CT) has only demonstrated a shrinkage of the pyramidal tract in the midbrain or pons during the chronic stage. We present a patient with frontoparietal subcortical hemorrhage in whom serial CT scans clearly demonstrated wallerian degeneration along the axis of the pyramidal tract early in the acute stage.


METHODS
A 63-year-old man with a history of hypertension suddenly developed a deterioration of consciousness, transcortical mixed aphasia, and dense hemiplegia on the right side. CT scans revealed a massive intracerebral hematoma in the frontoparietal subcortices of the left hemisphere. Although initial CT did not detect any hypodense areas along the left pyramidal tract below the hematoma, ill-defined areas of decreased density appeared in the posterior limb of the internal capsule, cerebral peduncle of the midbrain, and pontine base of the left side on day 13 after the stroke. These areas became well demarcated on day 22 and persisted thereafter.


CONCLUSIONS
An extensive hematoma can interrupt the pyramidal tract fibers that arise not only from the motor cortex and caudal premotor cortex but also from the somatosensory and parietal cortices, allowing very early CT demonstration of wallerian degeneration of the pyramidal tract.
Department of Medicine, National Cardiovascular Center, Osaka, Japan.
S
S
Kazui
Y
Y
Kuriyama
T
T
Sawada
S
S
Imakita
D002543:Cerebral Hemorrhage / Q000000981:diagnostic imaging*; D006406:Hematoma / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D008875:Middle Aged; D011712:Pyramidal Tracts / Q000000981:diagnostic imaging*; D013997:Time Factors; D014057:Tomography, X-Ray Computed; D014855:Wallerian Degeneration