Motivation: Neuroinflammation and glymphatic dysfunction in glioblastoma may extend beyond the tumor site, potentially affecting patient outcomes. Goal(s): To evaluate DTI-ALPS and free water imaging as biomarkers for assessing neurofluid dynamics in glioblastoma patients. Approach: We analyzed 277 patients with IDH wild-type glioblastoma, comparing tumor regions with normal-appearing white matter in both hemispheres and performed survival analysis. Results: Lower ALPS-index and higher free water volume fraction in contralateral normal-appearing white matter significantly associated with shorter survival time, independent of tumor volume, suggesting their utility as prognostic imaging biomarkers. Future applications could include patient selection and response monitoring for immunotherapy. Impact: Lower ALPS-index and higher free water volume fraction in contralateral normal-appearing white matter predict poor survival in glioblastoma patients. These non-invasive imaging biomarkers may help assess disease severity and monitor treatment response, potentially improving personalized therapeutic strategies in glioblastoma management.