A Histopathologic Correlation Study Evaluating Glymphatic Function in Brain Tumors by Multi-Parametric MRI.

ABSTRACT

PURPOSE: This study aimed to elucidate the impact of brain tumors on cerebral edema and glymphatic drainage, leveraging advanced imaging techniques to explore the relationship between tumor characteristics, glymphatic function, and aquaporin 4 (AQP4) expression. EXPERIMENTAL DESIGN: In a prospective cohort from March 2022 to April 2023, patients with glioblastoma, brain metastases, and aggressive meningiomas, alongside age- and sex-matched healthy controls, underwent 3.0T MRI, including Diffusion Tensor Imaging Analysis Along the Perivascular Space (DTI-ALPS) index and Multiparametric MRI (MTP) for quantitative brain mapping. Tumor and peri-tumor tissues were analyzed for AQP4 expression via immunofluorescence. Correlations between imaging parameters, glymphatic function (DTI-ALPS index), and AQP4 expression were statistically assessed. RESULTS: Among 84 patients (mean age 55 ± 12 years; 38 males) and 59 controls (mean age 54 ± 8 years; 23 males), brain tumor patients exhibited significantly reduced glymphatic function (DTI-ALPS index 2.315 vs. 2.879; p = 0.001) and increased cerebrospinal fluid (CSF) volume (201.376 cm³ vs. 115.957 cm³; p = 0.001). A negative correlation was observed between tumor volume and the DTI-ALPS index (r -0.715, p < 0.001), while AQP4 expression correlated positively with peritumoral brain edema (PTBE) volume (r 0.989; p < 0.001) and negatively with PD in PTBE areas (ρ -0.506; p < 0.001). CONCLUSIONS: Our findings highlight the interplay between tumor-induced compression, glymphatic dysfunction, and altered fluid dynamics, showing the utility of DTI-ALPS and MTP in understanding the pathophysiology of tumor-related cerebral edema. These insights provide a radiological foundation for further neuro-oncological investigations into the glymphatic system.