[MRI findings of closed head injury in children; with special reference to the effect of central shearing force].

It is considered that shearing effect as introduced by Holbourn may produce central concussion, diffuse brain swelling and diffuse axonal injury according to its grade of force. MRI was performed in 38 children who had been admitted to our hospital during the previous 1 year for the treatment of closed head injury of varying severity. In 8 out of 38 cases, abnormal high signal intensity was observed in the medial and para-medial brain parenchyma on MRI. All of these 8 cases suffered from head trauma caused by motor vehicle accidents. They included 2 cases of cerebral concussion, 1 of diffuse brain swelling, and 5 cases of diffuse axonal injury. In 2 cases of cerebral concussion, MRI (T2 weighted) revealed only localized high intensity in the corpus callosum, while CT showed normal and subarachnoid hemorrhage only at the interposium. These two children had been unconscious for periods of 20 to 30 minutes. In one case of diffuse brain swelling, MRI (T2W) showed a slightly obscure border between gray and white matter due to generally increased intensity. In 5 cases of diffuse axonal injury, most of these cases manifested lesions at the corpus callosum, deep white matter, periventricular gray matter, pons, midbrain and the cerebellum as demonstrated by high signal intensity on MRI (T2W) while CT in the acute stage showed small hemorrhage at the corpus callosum, corticomedullary junction and mid-brain and in the ventricles. Among these, two cases also demonstrated subdural hematoma and cortical contusional hemorrhage. At 3-4 weeks after injury, the area of high intensity previously demonstrated in the deep white matter and the corpus callosum on MRI (T2W) was reduced.(ABSTRACT TRUNCATED AT 250 WORDS)