Introduction: The most common primary tumors of brain are gliomas and tumor grading is essential for designing proper treatment strategies. The gold standard choice to determine grade of glial tumor is biopsy which is an invasive method. The purpose of this study was to investigatethe role of fiber density index ...

Purpose. To compare the sensitivity of MRS metabolites and MoCA and ACE‐R cognitive tests in the detection of radiation‐induced injury in low grade glioma (LGG) patients in early and early delayed postradiation stages. Methods. MRS metabolite ratios of NAA/Cr and Cho/Cr, ACE‐R and MoCA cognitive tests, and dosimetric parameters in corpus callosum were analyzed during RT and up to 6‐month post‐RT for ten LGG patients. Results. Compared to pre RT baseline, a significant decline in both NAA/Cr and Cho/Cr in the corpus callosum was seen at the 4th week of RT, 1, 3, and 6‐month post‐RT. These declines were detected at least 3 months before the detection of declines in cognitive functions by ACE‐R and MoCA tools. Moreover, NAA/Cr alterations at 4th week of RT and 1‐month post‐RT were significantly negatively correlated with the mean dose received by the corpus callosum, as well as the corpus callosum 40 Gy dose volume, i.e., the volume of the corpus callosum receiving a dose greater than 40 Gy. Conclusion. MRS‐based biomarkers may be more sensitive than the state‐of‐the‐art cognitive tests in the prediction of postradiation cognitive impairments. They would be utilized in treatment planning and dose sparing protocols, with a specific focus on the corpus callosum in the radiation therapy of LGG patients.

Background: The most common primary tumors of brain are gliomas. Grading of tumor is vital for designing proper treatment plans. The gold standard choice to determine the grade of glial tumor is biopsy which is an invasive method.Objective: In this study, we try to investigate the role of fractional anisotropy (diffusion anisotropy) and linear anisotropy coefficient (its shape) with the aim of Diffusion Tensor imaging (as a non-invasive method) in the grading of gliomas.Methods: A group of 20 patients with histologically glial approved was evaluated. In this study, we used a 1.5-Tesla MR system (AVANTO; Siemens, Germany) with a standard head coil for scanning. Multi-directional diffusion weighted imaging (measured in 12 non-collinear directions) and T1 weighted non-enhanced were performed for all patients. We defined two Regions of Interest (ROIs); white matter adjacent to the tumor and the homologous fiber tracts to the first ROI in the contralateral hemisphere.Results: Linear anisotropy coefficient (CL), fractional anisotropy (FA) values and ratios of low-grade peri-tumoral fiber tracts were higher than high-grade gliomas (P-value CLt=0.014, P-value CLt/n=0.019 and P-value FAt=0.006, P-value FAt/n=0.024).In addition, we perform ROC curve for each parameter (CL ratio-AUC = 0.82and FA ratio-AUC = 0.868).Conclusion: Our findings prove significant difference between diffusion anisotropy (FA) and diffusion shape (Cl) between low grade and high grade glioma, based on which we find this evaluation helpful in the grading of glial tumors.