Glioma delineation is complex and time-consuming. We evaluated whether a technically less challenging method could potentially bypass this tedious process, when using a simple manual circular-ROI by less trained personnel. We assessed whether applying a circular-ROI to clinical 3T-MRIs from 12 glioma patients, would extract significantly different GLI features. We compared it to the gold-standard manual delineation approach, having 3 observers with different levels of expertise placing the ROIs. Experience matters to extract consistent GLI features across delineation runs. The different ROI methods extracted significantly different GLI features, emphasizing the importance of delineation strategies when analyzing heterogeneous tumors like gliomas.