Tuberous sclerosis: magnetic imaging of the brain.

The results of the magnetic resonance imaging of three patients with proven tuberous sclerosis will be discussed. Cortical tubers and subcortical areas of junctional dysmyelination can be demonstrated clearly by MRI, whereas small calcifications may be missed because of low contrast if the chosen slice thickness should be too large. It is suggested that MRI should be applied to those patients with suspected tuberous sclerosis, in which CT has failed to demonstrate typical subependymal calcifications and to those in which doubts about the definite diagnosis remain. This should be done in order to improve the accuracy of genetic counselling. It may be argued that all patients with tuberous sclerosis have to be referred to MRI, because transformation of subependymal nodules into diffusely infiltrating gliomas can be detected earlier if comparison with a former MRI study is possible.