Spinal subarachnoid tumor seeding from intracranial metastasis: MR findings.

We describe the magnetic resonance findings in two cases of spinal subarachnoid seeding from an intracranial metastatic lesion. Magnetic resonance imaging techniques using T1 and intermediate T1-T2 pulse sequences improve anatomical definition of the spinal cord-thecal sac and allow for optimal contrast to define metastatic deposits in the subarachnoid space. Heavily T2 weighted pulse sequences do not appear to be useful in the diagnosis of subarachnoid metastases.