Leptomeningeal metastases: evaluation by gadolinium enhanced spinal magnetic resonance imaging.

BACKGROUND: Leptomeningeal metastases are common in patients with metastatic systemic cancer or certain primary brain tumors. They may be unsuspected clinically and may be missed by cerebrospinal fluid (CSF) cytology. We undertook a retrospective study of the diagnostic value of gadolinium enhanced spinal MR imaging in patients with known or at high risk for leptomeningeal metastases (LM).

MATERIAL AND METHODS: Ninety-six gadolinium enhanced MR examinations of the whole spine were performed in 61 patients (26 primary central nervous system tumors, 20 solid tumors and 15 lymphoproliferative neoplasms). All patients had detailed neurological evaluation and concomitant CSF examination.

RESULTS: Sixty-one MR's (62%) were positive, mostly in the lumbar spine. MR's were positive in 92% of patients with positive initial CSF cytology and in 60% of patients with negative CSF cytology. The MR examination was positive in 49% of those without clinical findings related to the spinal region. It showed disease beyond the symptomatic level in 42% of patients with spinal symptomatology. Multi-level spinal involvement was present in 57% of positive MR exams.

CONCLUSION: Enhanced spinal MR is sensitive for the detection of neoplastic spinal seeding. It detects LM in about 50% of high risk patients with negative initial CSF cytology or no spinal symptoms.