MRI diagnosis of intramedullary metastases from extra-CNS tumors.

The purpose of this study was to evaluate the topography, morphology and contrast enhancement of the intramedullary metastases (IM) from extra-CNS neoplasms. We report the results of a multicenter retrospective study on 18 patients with 26 IM examined with a 0.5T MR imaging system; intravenous injection of Gd-DTPA was performed in all cases. We found that the lesions are most frequently single, oval shaped, and small, with little or no deformation of the spinal cord (14 of 26 IM). They appear isointense on spin-echo T1-weighted images (24 of 26 IM), with a homogeneous and generally nodular high contrast enhancement after Gd-DTPA injection (21 of 26 IM), and present on T2- and proton-density-weighted sequences with a pronounced perilesional, pencil-shaped hyperintensity of the surrounding cord which is more evident in the cranial part of the cord referring to the IM.