Motivation: Different clinical managements are required for brain tumors such as glioblastoma, meningioma and metastases, with existing MRI techniques showing limitations in distinguishing them. Goal(s): The study aims to validate the utility of td-dMRI to enhance the accuracy of brain tumors characterization, using the IMPULSED model to distinguish microstructural distinctions. Approach: We used td-dMRI to explore microstructural mapping in glioblastoma, meningioma, and lung cancer patients with brain metastases by IMPULSED model, focusing on the parameters Dex, d, and vin to differentiate these brain tumors. Results: The cell size and extracellular diffusivity of these tumors are distinctly different. Impact: This study demonstrated that td-dMRI can non-invasively differentiate between glioblastomas, meningiomas and metastases. It proposes a potential change in diagnostic protocols, offering a pathway to more personalized management while reducing reliance on contrast agents.