Clinical analysis of crossed cerebellar diaschisis in patients with cerebrovascular

Crossed cerebellar diaschisis (CCD) is the phenomenon of decreased blood flow and altered metabolism in the contralateral cerebellum following supratentorial lesions. We evaluated CCD in patients with cerebravascular lesions using single photon emission tomography (SPECT) amd CBF tracer, ^<123>I- Iodoamphetamine (^<123>I-IMP), and considered the correlation between the development of CCD and many factors including the location and size of lesions, the degree of motor paralysis and the time from onset. Furthermore, we studied the effect of acetazolamide on cerebellar blood flow with SPECT. SPECT was performed in 86 patients with unilateral cerebral infarction and in 31 patients with cerebral hemorrhage. Acetazolamide test was performed in 17 patients with cerebrovascular lesions. There was no correlation between the occurrence of CCD and the time interval from onset. However, CCD tended to persist for a long time in patients whose degrees of CCD within the first month were severe. CCD was correlated with the severity of motor paralysis. CCD was present more frequently in patients with multilobular infarctions or subcortial infaractions including those of the internal capsule and/or corona radiata. Mean maximum hematoma diameters in patients with CCD were 56.4±7.4mm in putaminal hemorrhage and 29.5±6.8mm in thalamic hemorrhage. In these patients, hematomas were extended to the internal capsule or corona raciata. The acetazolamide test demonstrated that cerebellar vasoreactivity was intact in patients with CCD. MRI showed crossed cerebellar atrophy in a patient with presistent CCD. It is concluded that the development of CCD depends on the location and size of lesions, and that when hypoperfusion of the cerebellum persists for a long time, even if vasoreactivity is intact, irreversible degeneration of the cerebellum will occur.