MR images of leptomeningeal metastases from solid cancers: Prognostic implications of contrast-enhancement patterns

Background MRI is the first choice for the initial diagnosis of leptomeningeal metastasis (LM) from solid cancers. However, the prognostic implications of MRI for LM remain unclear. Herein, we evaluated them using multivariate analysis. Methods A retrospective analysis of 227 consecutive patients diagnosed with LM from 2008 to 2023 was conducted. Demographic data, MR images, and cerebrospinal fluid (CSF) examinations were collected. Survival analysis was conducted using Kaplan-Meier estimates, and prognostic factors were identified using Cox regression models. Results Primary cancers included lung (66.1%), breast (15.9%), and gastrointestinal (12.3%) cancers. All patients underwent MRI and 107 underwent CSF cytology at LM diagnosis. LM was diagnosed via MRI in 126 patients, cytology in 4, and both in 97. The mean follow-up time after LM diagnosis was 9.0 months. Median OS was 4.0 months [95%confidence interval (CI): 3.4-4.6]. Five MR patterns were identified: leptomeningeal contrast-enhancing (LCE) lesions of mixed (43.2%), linear (41.9%), nodular (9.3%) patterns, and no LCE lesions with (4.0%) or without hydrocephalus (1.8%). Patterns transitioned in 41.8% of 129 patients over time. Multivariate analysis demonstrated significantly worse prognosis in mixed pattern (hazard ratio (HR) 2.07 [95%CI: 1.24-3.44]), gastrointestinal cancer (HR 2.50 [95%CI: 1.47-4.23]), and KPS < 50% (HR 1.73 [95%CI: 1.26-2.39]). Systemic therapy (HR 0.33 [95%CI: 0.23-0.49]) and radiotherapy (HR 0.57 [95%CI: 0.41-0.78]) after LM showed significant survival benefits. Conclusions MR image patterns represent a dynamic spectrum of LM, and the mixed pattern may predict poor outcomes. Further research on correlation of MR image features and pathophysiological results is anticipated.