Yi Wah Eva Cheung
Tung Wah College, Hong Kong
Title: The role of structural MRI and functional MRI in brain tumor characterization
Biography
Biography: Yi Wah Eva Cheung
Abstract
Purpose: to evaluate the effectiveness of using functional MRI in differentiation of brain tumors, using Apparent Diffusion Coefficient (ADC) values.
Material and method: 3T brain MR images were reviewed retrospectively in 66 patients with 73 brain tumors comprised of different types of malignant tumors. The MR protocol included T1w, T2w, T1w + C, and DW-MRI was performed using single-shot echoplanar (EPI) sequence with b gradient factor value of 0, 500 and 1000 s/mm2 in the three orthogonal axes. Five regions of interest (ROI) with volume of 5 ± 1.5 mm3 were placed on tumor areas and the minimum Apparent Diffusion Coefficient (ADC MIN) values were obtained, necrotic and vasogenic edema area and correlated with the histopathology results. ADC MIN values between Lymphoma vs GBM, Atypical Meningioma vs Meningioma, Lymphoma vs Demyelination, GBM vs metastatic tumor, Low grade Glioma vs High grade Glioma, were compared using Mann-Whitney test . The ADC MIN values in different types of gliomas were assessed using Kruskal-Wallis test with pairwise multiple comparison.
Results: The mean ADC MIN is significant lower in patients with Lymphoma (0.716 x10-3 mm2/sec) than GBM (1.052 x10-3 mm2/sec) (p=0.001); the mean ADC MIN of Atypical Meningioma (0.755 x10-3 mm2/sec) is significantly lower than Meningioma (1.114 x10-3 mm2/sec) (p=0.012); the mean ADC MIN of Lymphoma (0.716 x10-3mm2/sec) is significantly lower than Demyelination (1.832 x10-3 mm2/sec) (p=0.057). The mean ADC MIN values between GBM (1.052 x10-3 mm2/sec) and metastatic tumor (0.8-1.1 x10-3 mm2/sec) were similar, which cannot be used to differentiated (p=0.910). Regarding gliomas, the mean ADC MIN of high grade gliomas (1.064 x10-3 mm2/sec) is significant lower than that of low grade gliomas (1.455 x10-3 mm2/sec) (p=0.001).The mean ADC MIN of Necrotic tumors is 2.234mm2/sec and the mean ADC MIN vasogenic edema is 1.319 mm2/sec.
Conclusion: The ADC MIN values provide practical information which can be used for the differentiation of specific brain tumor histology as well as glioma types. DWI can improve imaging diagnosis in the clinical setting, compared to using structural MRI scans alone.