MR imaging of intracranial arachnoid cysts.

The magnetic resonance characteristics of 16 intracranial arachnoid cysts were evaluated and several features identified that allowed the differentiation from other cystic lesions. Uncomplicated arachnoid cyst contents respond like CSF to both T1 and T2 weighted sequences. Signal from the contiguous brain is of normal intensity. The absence of signal from cortical bone and the ease of obtaining multiplanar views enable the margins of the cyst, its contents, and the full extent of the lesion to be easily defined.