CLINICAL APPLICATION OF SATURATION TRANSFER MRI FOR DIFFERENTIATING TUMOUR PROGRESSION FROM RADIATION NECROSIS IN BRAIN METASTASES

Abstract Stereotactic radiosurgery for the treatment of brain metastases delivers a high dose radiation with excellent local control, but increases likelihood necrosis. As shown in our previous work, saturation transfer MRI, consisting quantitative magnetization (qMT) and chemical exchange (CEST), is promising technique distinguishing necrosis (RN) from tumour progression (TP) metastases. A 3D qMT/CEST acquisition was recently implemented over 100 patients have been scanned to date. The purpose this work assess ability advanced MRI parameters, including qMT CEST metrics, which are sensitive macromolecules metabolism. specific metrics that were explored included amide NOE contributions ratio (MTR), MTR asymmetry, apparent exchange-dependent relaxation (AREX), semi-solid pool fraction T1 T2 times. For subset patients, dynamic susceptibility contrast (DSC) perfusion images acquired. Examples confirmed cases will be presented, comparing structural (pre- post-contrast T1-weighted FLAIR images) parameter maps also relative cerebral blood flow (rCBF) DSC imaging. Interim cohort results presented. Approaches standardizing parameters across multiple vendors explored.