A STUDY OF MAGNETIC RESONANCE RELAXOMETRY, DIFFUSION KURTOSIS AND
PERFUSION IMAGING IN NON-ENHANCING DIFFUSE BRAIN GLIOMAS WITH
INTRAOPERATIVE NEURONAVIGATION: ANALYSIS OF TUMOR HETEROGENEITY AND SEARCHING FOR NEUROIMAGING PREDICTORS OF PROLIFERATIVE ACTIVITY
Chekhonin I.V., Batalov A.I., Pogosbekian E.L., Tyurina A.N., Galstyan S.A., Bykanov A.E., Pitskhelauri D.I., Zakharova N.E., Pronin I.N.
N.N. Burdenko National Medical Research Center of Neurosurgery. Moscow, Russia.
Purpose. To study the capability of MR relaxometry, diffusion kurtosis imaging, and ASL perfusion to distinguish between foci of different proliferation activity in non-enhancing brain gliomas and to assess the correlations between quantitative imaging values and distance from the tumor margin (as determined by conventional MRI).
Materials and methods. The study enrolled 24 patients with primary diffuse supratentorial non-enhancing gliomas (8 – grade 2, 16 – grade 3). The diagnostic protocol included MR relaxometry, diffusion kurtosis imaging, and ASL-perfusion. Prior to the surgery, regions of interest corresponding to the sites of biopsy along the planned approach were selected. During the tumor removal, tissue specimens were acquired and located with the neuronavigation system, and every biopsy focus was matched to a particular region of interest on quantitative MR maps. Ki-67 labeling index (LI) was measured in every tissue specimen to determine the proliferative activity. We studied the correlations between MR values and the distance from the tumor margin as well as between MR values and proliferative activity.
Results. We demonstrated significant direct correlations between the distance from tumor margin and T2, mean diffusion (MD), T1, and inverse correlations between the distance from tumor margin and axonal water fraction (AWF), radial kurtosis (RK), mean kurtosis (MK), axial kurtosis (AK), fractional anisotropy (FA), tumor blood flow (TBF). Correlations (p<0,05) between the measured distance and radial extra-axonal space diffusivity (RadEAD), tortuosity of extra-axonal space (TORT), and axial extra-axonal space diffusivity (AxEAD) did not show significance after multiple testing adjustments. Direct correlations (p<0,05) between Ki-67 LI and AxEAD, MD, RadEAD, Т1, Т2 as well as an inverse correlation between Ki-67 LI and AWF were not significant after multiple testing adjustments. Despite this fact, values of AWF showed ability to differentiate tumor regions with Ki-67 LI lower than 8% and of 8% and higher. AxEAD, MD, MK, RadEAD, T1, T2 differed between regions with Ki-67 LI lower than 6% and of 6% and higher.
Discussion. The variations in magnetic resonance relaxometry and diffusion kurtosis imaging values in areas with different Ki-67 LI can be attributed to the increased hydration and mobility of water molecules associated with heightened cellular proliferation. This finding contrasts with previous studies on more malignant gliomas, where regions of elevated cell division exhibited reduced tissue water content, increased diffusion restriction, and augmented blood flow due to neoangiogenesis. Increased mean diffusivity, T1 and T2 relaxation times, along with reduced axonal water fraction, kurtosis, and fractional anisotropy in centrally located tumor regions, can be attributed to lower cellular density and higher hydration levels compared to the periphery. The elevated perfusion observed in peripheral tumor areas is likely linked to the physiological increase in vascularization near the cerebral cortex and is not considered indicative of a higher degree of tumor anaplasia, as no significant correlations between perfusion and proliferation were found in our sample.
Conclusion. Magnetic resonance relaxometry and diffusion kurtosis imaging allow predicting regions with higher proliferative activity in non-enhancing gliomas. The tumor tissue of these gliomas shows heterogeneity with the core region being more hydrated and less structured.
Keywords: glioma, infiltration, proliferation, Ki-67, magnetic resonance relaxometry, MAGiC, diffusion kurtosis imaging, ASL-perfusion.
Corresponding author: Chekhonin I.V., e-mail: Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript , Этот e-mail адрес защищен от спам-ботов, для его просмотра у Вас должен быть включен Javascript
For citation: Chekhonin I.V., Batalov A.I., Pogosbekian E.L., Tyurina A.N., Galstyan S.A., Bykanov A.E., Pitskhelauri D.I., Zakharova N.E., Pronin I.N. A study of magnetic resonance relaxometry, diffusion kurtosis and perfusion imaging in non-enhancing diffuse brain gliomas with intraoperative neuronavigation: analysis of tumor heterogeneity and searching for neuroimaging predictors of proliferative activity. REJR 2025; 15(2):109-119. DOI: 10.21569/2222-7415-2025-15-2-109-119.
Received: 18.02.25 Accepted: 03.04.25