Diffusion Kurtosis Imaging Reflects GFAP, TopoIIα, and MGMT Expression in Astrocytomas

Abstract

Objective: Preliminary study of magnetic resonance (MR) diffusion kurtosis imaging (DKI) assessing the pathological glial fibrillary acidic protein (GFAP), TopoIIα, and O 6-methylguanine–DNA methyltransferase (MGMT) expression in astrocytomas. Materials and Methods: This study was approved by the local ethics committee, and informed consent was obtained from all participants. Sixty-six cases with pathologically proven astrocytomas were enrolled in this study; of which, 34 were high grade and remaining 32 were low grade. They patients underwent conventional MRI head scan, DKI scan, and enhanced scan under the same conditions. Fractional anisotropy (FA) and mean kurtosis (MK) calculated from DKI, as well as GFAP, TopoIIα, and MGMT expression level were compared prospectively between high and low-grade astrocytomas. Spearman rank correlation analysis was used for comparing values of DKI and GFAP, TopoIIα, and MGMT expression level in the two groups. Results: The MK values were significantly higher in high-grade astrocytomas than those in low-grade astrocytomas ( P < 0.05); FA values demonstrated no significant difference between the two groups ( P = 0.331). GFAP expression level was significantly lower in high-grade astrocytomas than in low-grade astrocytomas ( P < 0.05). Topo-IIα expression level were significantly higher in high-grade astrocytomas than in low-grade astrocytomas ( P < 0.05). There was no significant difference in MGMT expression level between the two groups ( P = 0.679). MK values were negatively correlated with the expression of GFAP ( r = -0.836; P = 0.03), however, they were positively correlated with the expression of Topo-IIα ( r = 0.896; P = 0.01). FA values were not correlated with the expression of GFAP ( r = 0.366; P = 0.05), Topo-IIα ( r = −0.562; P = 0.05), and MGMT ( r = −0.153; P = 0.10). Conclusion: MK, the DKI parameter values of astrocytomas, was significantly correlated to the expression of GFAP and TopoIIα. To a certain extent, applying DKI may provide the biological behavior of tumor cell differentiation, proliferation activity, invasion and metastasis, and can guide individual treatment.