[MR imaging of traumatic cerebellar dysfunction]

Four cases of cerebellar dysfunction following head trauma are presented. Cerebellar signs revealed were those such as dysmetria, dysdiadochokinesis, horizontal nystagmus and ataxia. T2-weighted magnetic resonance (MR) imaging (0.15 tesla, spin-echo method; TR 2000 msec. and TE 100 msec.) revealed focal lesions in these patients, although CT scan failed to demonstrate any changes in the cerebellum. The cerebellar symptoms were maximal immediately after the trauma but improved gradually in two cases. These are compatible with the transient traumatic cerebellar dysfunction postulated by R. C. Cantu in 1969. The pathophysiology of this syndrome, whether it is due to cerebellar concussion or contusion, has not yet been determined. The abnormality of the cerebellum revealed by MR imaging seemed to be contusion rather than concussion. Therefore the authors presume that transient traumatic cerebellar dysfunction is caused by minor cerebellar contusion. In the other two cases, delayed epidural hemorrhage ensued and the symptoms disappeared rapidly after evacuation of the hematoma. In these patients, occurrence of delayed epidural hematoma in the posterior cranial fossa was predicted by MR imaging. The authors regard the lesion as an alarm signal indicating the probable occurrence of infratentorial hematoma.