In vivo MR Measurement of Refractive Index, Relative Water Content and T2 Relaxation time of Various Brain lesions With Clinical Application to Discriminate Brain Lesions

Abstract

PURPOSE: Refractive index (RI) is unique in discriminating various tissues. It is dependent on water and solid components such as protein and phospholipid of brain tissue resembling hydrogel. Our purpose was to determine RI of normal and pathological tissues of brain from the MR T2 relaxation time (T2 value) to determine relative water and solid contents of a tissue and discriminate various pathological lesions by the help of RI in T2 weighted MR images.METHODS: In a 0.3 Tesla permanent and 3 Tesla superconductor magnets T2 maps were created along with T2 shades to get T2 value of various brain tissue homogenates prepared from biopsy samples of known RI using multi-echo datasets by a read out train. T2 value of CSF, gray/white matter and various pathological lesions were determined.From the relationship of RI and T2, a RI map of brain and RI shade were produced. Computer generated RI and color coded map of T2 weighted images of various lesions were created. RESULTS: Analyzing various RI of pathological lesions it was noted that, RI of malignant lesions were more than 1.421 whereas RI of benign lesions were less than 1.395CONCLUSION: RI and color coded map may discriminate between benign and malignant lesions of brain.