Comparative spine imaging in leptomeningeal metastases

Sixty-one patients (34 men; 27 women) ranging in age from 1-74, median 40 years with leptomeningeal metastases (LM) as defined by either positive CSF cytology (85%) or a clinical syndrome and compatible neuroradiographic findings (15%) underwent CT-myelographic (CT-M), spine MR (S-MR) and 111Indium-DTPA CSF flow studies (FS). Each patient underwent sequential spine imaging (CT-M, S-MR and FS) over a median of 5 days. In 57% of patients, all 3 spine imaging modalities were normal. 43% of patients demonstrated abnormalities on spine imaging; 33% had abnormal FS, 34% showed abnormalities on S-MR and 33% had abnormalities by CT-M. FS were most sensitive for detecting interruption of CSF flow whereas CT-M and S-MR better demonstrated nerve root thickening (CT-M approximately S-MR), cord enlargement (CT-M > S-MR), subarachnoid nodules (S-MR > CT-M), intraparenchymal cord tumor (S-MR > CT-M) and epidural spinal cord compression (S-MR = CT-M). In conclusion, patients with LM frequently require spine imaging and the results of this study suggest both S-MR and FS provide the best radiographic assessment wherein S-MR is superior for detecting bulky disease and FS best demonstrates interruption of CSF flow.