Evaluating The Correlation Between Lipid Level In Mr Spectroscopy And Signal Loss Ratio In Chemical Shift (Ip/Op) Images In Brain Gliomas

Abstract

Introduction:<br /> Gliomas are the most common malignant primary brain tumors. Magnetic resonance spectroscopy has been used for grading these lesions. It has been shown that the amount of free tumor lipid metabolites is a promising indicator to detect aggressive tumors. This method is time-consuming, technically demanding and associated with imaging artifacts in certain parts of brain. It is also not available in all imaging centers.<br /> Assuming that gradient echo chemical shift imaging (In phase / opposed phase) technique is capable of evaluating intracellular lipids, we conducted a study to compare the results of chemical shift imaging and MRS in patients with brain glioma.<br /> Material and Methods:<br /> In this study, 33 patients with a cerebral glioma (18 males and 15 females) with a mean age of 43 years were subjected to MRI imaging test using 1.5 Tesla magnet. Magnetic Resonance Spectroscopy and chemidcal shift sequences were performed in all patients. The MRS spectrum was evaluated to assess the free lipid metalbolites withint the tumor. We also calculated the signal loss ratio in a ROI placed in the solid part of the tumor.<br /> Results:<br /> Spearman's correlation showed a significant correlation between signal drop in chemical shift imaging and lipid and lipid-lactate levels in MRS (p value < 0.01).<br /> Conclusion:<br /> This study showed a significant correlation between the free lipid level in MRS and signal drop in chemical shift images. Considering the limitations of magnetic resonance spectroscopy, and importance of evaluating the amount of free lipids in brain gliomas regarding tumor staging, we suggest that SLR in IP/OP imaging is a major step towards improving the evaluation of lipid levels in these tumors and is helpful in determining patients' prognosis and tumor grading.