Association of Radiomics and Metabolic Tumor Volumes in Radiation Treatment of Glioblastoma Multiforme

Abstract Purpose High-throughput extraction of imaging and metabolomomic quantitative features from MRI and MR Spectroscopy Imaging (MRSI) of Glioblastoma Multiforme (GBM) results in tens of variables per patient. In radiotherapy (RT) of GBM the relevant metabolic tumor volumes (MTVs) are related to aberrant levels of N -Acetylaspartate (NAA) and Choline (Cho). The corresponding Clinical Target Volumes (CTVs) for RT are based on Contrast-Enhancing T1-weighted (CE-T1w) and T2-weighted (T2w)/FLAIR MRI. The objective is to build a framework for investigation of the associations between imaging, CTVs, and MTVs features for better understanding of the underlying information in the CTVs and dependencies between these volumes. Methods and Materials Necrotic portions, enhancing lesion and edema were manually contoured on CE-T1w/T2w images for 17 GBM patients. CTVs and MTVs for NAA (MTVNAA ) and Cho (MTVCho ) were constructed. Imaging and metabolic features, related to size, shape, and signal intensities of the volumes were extracted. Tumors were also scored categorically for ten semantic imaging traits by a neuroradiologist. All features were investigated for redundancy. Two-way correlations between imaging and CTVs/MTVs features were visualized as heat maps. Associations between MTVNAA and MTVCho and imaging features were studied using Spearman’s correlation. Results Forty-eight imaging features were extracted per patient. Half of the imaging traits were replaced with automatically extracted continuous variables. Twenty features were extracted from CTVs and MTVs. A series of semantic imaging traits were replaced with automatically extracted continuous variables. There were multiple (22) significant correlations of imaging measures with CTVs/MTVNAA while only 6 with CTVs/MTVCho. Conclusions A framework for investigation of co-dependencies between MRI and MRSI radiomic features and CTVs/MTVs has been established. MTVNAA was found to be closely associated with MRI volumes, while very few imaging features were related to MTVCho , indicating that Choline provides additional information to imaging.