傍矢状部白質剪断損傷—びまん性軸索損傷に伴う片麻痺の画像所見

Parasagittal White Matter Shearing Injury (So-called Gliding Contusion):Possible radiological evidence of hemiplegia in diffuse axonal injury

I．はじめに

　びまん性軸索損傷diffuse axonal injuryには痙性片麻痺／四肢麻痺が合併しやすい^8）．Jennetら^4）は重症頭部外傷の半数に片麻痺が発生すると指摘し，その機序として深部白質病変を示唆している．しかし，片麻痺の責任病変部位はいまだ明確にされていないのが実情である．われわれはびまん性軸索損傷を含むびまん性脳損傷の臨床例を集め，痙性片麻痺／四肢麻痺症状の有無とともにCT・MRI所見を検討した．その結果，傍矢状部白質の剪断損傷（いわゆるgliding contusion）^1）が関連する可能性を見出したので，報告する．

Severe head injury or diffuse axonal injury is fre-quently associated with spastic hemiplegia/paraplegia However, the causative lesion has not been well eluci-dated. Especially, the relationship between the gliding contusion and spastic hemiplegia has not been inferred yet. We have analyzed 6 brain concussion cases and 19 cases of diffuse axonal injury. None of the concussion cases experiened hemiplegia in their courses. Among the 19 cases, 10 were left with persistent and disabling hemiplegia/quadriplegia, whereas 5 showed persistent but mild hemiplegia. Among the 10 cases, one was in-capacitated by a brainstem hemorrhage. The remaining 9 cases exhibited, in the parasagittal white matter, small hemorrhagic spots in the acute phase CT, low-density areas in the chronic phase CT, and/or T2 high and T1 low signal lesions in the MRI. In 8 cases, the lesion was in accord with the hemiplegic side, but in one case the low density area was on the ipsilateral side. Two of the 3 cases showing quadriplegia exhi-bited bilateral parasagittal lesions. None of the 5 mild hemiplegia cases and 10 nonhemiplegia cases showed such abnormality. Superficial brain contusions were found in 17 cases altogether, but they were not at all correlated with the occurrence of hemiplegia. Thus, it was concluded that parasagittal white matter shearing injury or so called gliding contusion could be the man-ifestation of injury to the corticospinal tract in the coro-na radiata.