NIMG-76. POST-GADOLINIUM 3-DIMENSIONAL SPATIAL, SURFACE, AND STRUCTURAL CHARACTERISTICS OF GLIOBLASTOMAS DIFFERENTIATE PSEUDOPROGRESSION FROM TRUE TUMOR PROGRESSION

PURPOSE: Pseudoprogression is often indistinguishable from true tumor progression on conventional 2-dimensional (2D) MRI in glioblastoma multiforme (GBM) patients. The aim of this study was to determine the association between post-gadolinium 3-dimensional (3D) characteristics and clinical state in GBM patients. METHODS: Standardized 3D brain MRI studies were performed, and contrast enhancing portions of each tumor were segmented and analyzed blinded to clinical state using principal component analysis (PCA), medial axis transformation (MAT), and coverage analysis. Associations between the 3D characteristics of the post-gadolinium enhanced regions and the clinical status of patients were performed. RESULTS: A total of 15 GBM patients (male: 11 (73%); median age (range): 62 years (36–72 years)) with a median disease duration of 6 months (range: 2–24 months) were studied cross-sectionally with 6 (40%) patients identified with tumor progression. Post-gadolinium features corresponding to the group with progressive disease exhibited a more spherical and symmetric shape relative to their stable counterparts (p