The diffusion tensor image analysis along the perivascular space (DTI-ALPS) method has been developed to evaluate glymphatic function. In order to evaluate wider clinical cases, we developed a diffusion weighted image ALPS (DWI-ALPS) technique. The ALPS-index was retrospectively calculated by clinical DWI of normal subjects and those with pathologies. In normal subjects, the ALPS-index was highest in those in their forties and lowest in those in their seventies. Patients with Alzheimer’s disease and subdural hematoma showed a lower ALPS-index than age-matched normal subjects. The DWI-ALPS method seems to be feasible for evaluation of glymphatic function in the clinical practice.