Diffusion tensor imaging effectiveness for staging the glial tumors at 3 Tesla MRI

Purpose:Determination the peritumoral invasion and staging the glial tumors by conventional brain Magnetic Resonance Imaging (MRI) has difficulties. Diffusion Tensor Imaging (DTI) of the glial tumors detect the microstructural changes which is undetectable by conventional MRI. The purpose in this study is to evaluate the efficiency of FA and ADC values in the glial tumors staging and determine the peritumoral invasion which are calculated in DTI.Materials and Methods:MRI and DTI were performed retrospectively in 33 glial tumor lesion in 33 patients (23 male, 10 female, age range 25-81, mean age 51.18). The study grup consists of 12 low grade ( Grade I-II) and 21 high grade (Grade III-IV) with a histologically proven diagnosis.At conventional MRI, morphological features of the lesions, intratumoral cystic-necrotic and hemorrhagic areas, and contrast enhancement pattern which might be useful in the differential diagnosis were evaluated. In DTI, FA and ADC values were calculated by the ROIs from the solid portion of the tumor which were intense contrast enhancement and doesn?t include cystic, necrotic and hemorrhagic areas, adjacent 1 and 2 cm parenchym to tumors and contralateral normal brain parenchym. These results were compared with histopathological findings.Results:Conventinal brain MRI findings revealed a sensitivity of %63 and a rate of correct diagnosis of %100 in differentiating low grade and high grade glial tumors. However, separating low grade tumors with conventional MRI was more sensitive.In the second parth of the study, a significant correlation was found between low-high grade glial tumors compared with normal parenchym from the measured FA and ADC values (p<0,001). The FA and ADC measurements from the adjacent 1 and 2 cm parenchym to tumor compared with normal parenchym, FA measurements were statistically significant (p<0,05). Looking at the ADC values, only for high grade adjacent 1 cm parenchym from the measurements were statistically significant (p<0,05). However, between high and low grade glial tumors were evaluated, only the tumor within the measured FA values were statistically significant (p<0,05). ADC and FA values measured in adjacent tumor parenchyma was not significant.Conclusion:DTI add important information to conventional brain MRI findings in the staging of the glial tumors and determining the peritumoral invasion of the glial tumors. In DTI, staging the low and high grade glial tumors and identifed the peritumoral invasion of the glial tumors, the FA values gives more important information than ADC values. Therefore, these results suggest that preoperative non-invasive idendification of low and high grade glial tumors and determined the peritumoral invasion eliminate unnecessary indications for biopsy, guide the surgeon before the surgery and significantly reduces the mortality rate.