Decreased diffusion in central pontine myelinolysis

Two patients with central pontine myelinolysis (CPM) were studied with diff usion-weighted MR imaging 1 week after onset of tetraplegia. In both patien ts, affected white matter showed hyperintensity on diffusion-weighted image s associated with a decrease in apparent diffusion coefficient (ADC) values . In one patient studied serially, ADC values normalized by 3 weeks after t etraplegia. Early in the clinical course, diagnosis of CPM can sometimes be difficult. Hyperintensity on diffusion-weighted images may therefore have diagnostic utility. Decreased lesional ADC values support the notion that C PM is a consequence of relative intracellular hypotonicity.