July 28th, 2026
A magnetic resonance imaging (MRI) approach known as diffusion tensor image analysis along the perivascular space (DTI-ALPS) can be used to measure the flow of cerebrospinal fluid leaving the brain via the glymphatic system, a network of vessels that parallels blood vessels passing out of the brain. This drainage of cerebrospinal fluid allows metabolic waste to leave the brain, but becomes progressively ever more impaired with advancing age. It is thought that this loss of drainage leads to a build up of protein aggregates such as misfolded amyloid-β that contribute to the onset and progression of neurodegenerative conditions. Here researchers review the evidence for a reduced drainage rate measured via DTI-ALPS to correlate with established measures of the progression of Alzheimer's disease. One might recall that some animal studies have shown that forcing an increase in glymphatic flow of cerebrospinal fluid has produced a reduction in neurodegenerative pathology.
Although the diffusion tensor image analysis along the perivascular space (DTI-ALPS) index is widely utilized as a proxy for glymphatic function in Alzheimer's Disease (AD) research, its association with core AD pathological biomarkers remains inconclusive due to inter-study heterogeneity. This systematic review aimed to investigate associations between the DTI-ALPS index and AD biomarkers and to elucidate potential sources of heterogeneity.
