Tumor infiltration in enhancing and non-enhancing parts of glioblastoma: a correlation with histopathology

Purpose: To correlate histopathologic findings from biopsy specimens with their corresponding location within enhancing areas, nonenhancing areas and necrotic areas on contrast enhanced T1-weighted MRI scans (cT1). Materials and methods: In 37 patients with newly diagnosed glioblastoma who underwent stereotactic biopsy, we obtained a correlation of 5611 [mm.sup.3] biopsy specimens with their corresponding position on the intraoperative cT1 image at 1.5 Tesla. Biopsy points were categorized as enhancing (CE), non-enhancing (NE) or necrotic (NEC) on cT1 and tissue samples were categorized as viable tumor cells, blood or necrotic tissue (with or without cellular component). Cell counting was done semi-automatically (Figure). Results: NE had the highest content of viable tumor cells (89% vs. 60% in CE and 30% NEC, respectively, p. Discussion The appearance of a glioblastoma on a cT1 image (circular enhancement, central necrosis, peritumoral edema) does not correspond to its diffuse histopathological composition. Cell density is elevated in both CE and NE parts (which do not differ significantly). Hence, our study suggests that NE contains considerable amounts of infiltrative tumor with a high cellularity which should be considered in resection planning.