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Updated: Aug 15, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Diffusion Tensor Imaging Analysis Along the Perivascular Space (DTI-ALPS) as an Imaging Biomarker of Glymphatic
Siddharth R Shah1, Muhammad Saeed Qazi1, Muhammad Riyyan1
1From the Department of Neurosurgery (S.R.S., R.H., G.F.W., D.G.), Diagnostic Radiology and Nuclear Medicine (G.F.W., D.G.), Brain Tumor Program (S.R.S., R.H., G.F.W., D.G.), Greenebaum Comprehensive Cancer Center, University of Maryland School of Medicine, Baltimore, MD, USA and Department of Internal Medicine (M.S.Q., M.R.), University of Florida, Gainesville, Fl, USA.
Background:
Diffusion tensor imaging analysis along the perivascular space (DTI-ALPS) is an noninvasive MRI biomarker of perivascular/glymphatic diffusivity. Although individual studies suggest that gliomas are associated with disrupted glymphatic function, the magnitude and consistency of DTI-ALPS alterations have not been systematically evaluated.
Purpose:
To systematically evaluate DTI-ALPS-index differences between glioma patients and healthy controls and to investigate associations with tumor grade, Isocitrate Dehydrogenase(IDH) mutation status, and tumor laterality.
Data Sources:
PubMed, Embase, and Scopus were searched from database inception through May 2026.
Study Selection:
Human studies reporting DTI-ALPS-index values in glioma patients and healthy controls were included.
Data Analysis:
Mean differences(MDs) were pooled using random-effects inverse-variance meta-analysis.
Data Synthesis:
Seven comparator cohorts including 628 glioma patients and 309 healthy controls were included. Glioma patients demonstrated significantly lower ALPS-index values than healthy controls(MD, -0.18; 95% CI, -0.23 to -0.14; P<.00001; I2=70%). Lower-grade gliomas had higher ALPS-index values than higher-grade gliomas(MD, 0.11; 95% CI, 0.01-0.21; P=.03; I2=96%). The primary differences between IDH-mutant and IDH-wildtype gliomas(MD, 0.09; 95% CI, -0.01 to 0.18; P=.07; I2=95%) and between tumor-ipsilateral and contralateral hemispheres(MD, -0.04; 95% CI, -0.08 to 0.01; P=.12; I2=78%) were not statistically significant. Exploratory sensitivity analyses excluding one influential cohort yielded statistically significant grade-, IDH-, and laterality-based differences with reduced heterogeneity; however, these findings were dependent on cohort exclusion and should be considered hypothesis-generating.
Limitations:
The evidence is limited by few studies, high heterogeneity, methodological differences in DTI-ALPS measurement, and observational study designs, with some subgroup results changing when individual cohorts are excluded.
Conclusions:
Gliomas are associated with reduced DTI-ALPS-index values compared with healthy controls, indicating impaired perivascular/glymphatic diffusivity. However, associations with tumor grade, IDH status, and laterality remain uncertain due to heterogeneity and sensitivity to individual studies. DTI-ALPS is a promising noninvasive biomarker of disease-associated brain-fluid transport dysfunction, but requires prospective validation, including in studies of transport-modulating interventions.
