Assessing glymphatic dysfunction using the diffusion tensor image analysis along the perivascular space (DTI-ALPS)...

To evaluate glymphatic dysfunction using the diffusion tensor image analysis along the perivascular space (DTI-ALPS) index in patients with low-grade gliomas (LGGs), high-grade gliomas (HGGs), and metastases, assess its feasibility as a non-invasive biomarker for tumour differentiation, and examine its relationship with tumourspecific characteristics.

This single-centre retrospective study examined patients with LGGs (n = 30), HGGs (n = 30), and metastases (n = 20), calculating the DTI-ALPS index. Tumour volume, peritumoral oedema, tumour volume-to-total brain volume ratio (TV/TBV), and peritumoral oedema-to-total brain volume ratio (PTE/TBV) were obtained using 3D segmentation. The DTI-ALPS index was compared across the 3 tumour groups, and its relationships with tumour-associated oedema, peritumoral oedema, TV/TBV, and PTE/TBV were analysed within and between the groups. Additionally, the DTI-ALPS index was compared between isocitrate dehydrogenase-1 (IDH1) mutant and IDH1 wild-type gliomas.

There was a significant difference in the DTI-ALPS index between the 3 groups (p < 0.001), with HGGs having the lowest DTI-ALPS index values, followed by metastases and LGGs. Receiver operating characteristic (ROC) analysis showed that the DTI-ALPS index had excellent sensitivity and specificity for LGGs (> 1.3838) and HGGs (< 1.317). No significant correlation was found between the DTI-ALPS index and tumour volume, TV/TBV, PTE/TBV, or peritumoral oedema. Furthermore, the mean DTI-ALPS index in IDH1 wild-type gliomas (1.23 ± 0.08) was significantly lower than that observed in IDH1 mutant tumours (1.42 ± 0.10; p < 0.001).

The DTI-ALPS index provides valuable insights into glymphatic dysfunction in brain tumours. This study underscores its potential as a non-invasive biomarker in differentiating these tumour groups.