The MRI diagnosis of lung cancer intramedullary spinal cord metastasis

Objective To discuss the MRI features and pathogenic mechanisms of lung cancer intramedullary spinal cord metastasis (ISCM). Methods Four cases with clinically and 3 cases pathologically proved lung cancer ISCM were analyzed retrospectively. Turbo spin-echo sequence T 1 and T 2 weighted images were acquired in all patients. T 1 weighted images were obtained after intravenous administration of Gd-DTPA in all patients. Results A total of 7 ISCM were displayed by MR studies. The tumor occurred in thoracic cord (3/7) and in medullary cone (4/7). The tumor involved the central aspect of the cord. The lung cancer ISCM showed hypointensity (n=1) or isointensity (n=6) on T 1WI and hyperintensity on T 2WI. The extensive cord enlargement with cyst formation or syringomyelia was common. On contrast study, all tumors showed marked homogenous enhancement with clear borders. Conclusion The lung cancer ISCM usually presented as solitary lesions with marked contrast enhancement. The extensive cord enlargement was common in all patients. Because of the limitation in the evaluation of lung cancer ISCM on MRI, definite diagnosis of lung cancer ISCM depended on combination of clinical and MRI data.