Mapping therapeutic response in a patient with malignant glioma

Short-interval scanning of patients offers a detailed understanding of the natural progression of tumor tissue, as revealed through imaging markers su ch as contrast enhancement and edema, prior to therapy. Following treatment , short-interval scanning can also provide evidence of attenuation of growt h rates. We present a longitudinal imaging study of a patient with glioblas toma multiforme (GBM) scanned 15 times in 104 days on a 3 T MR scanner. Ima ges were analyzed independently by two automated algorithms capable of crea ting detailed maps of tumor changes as well as volumetric analysis. The alg orithms, a nearest-neighbor-based tissue segmentation and a surface-modelin g algorithm, tracked the patient's response to temozolomide, showing an att enuation of growth. The need for surrogate imaging end-points, of which gro wth rates are an example, is discussed. Further, the strengths of these alg orithms, the insight gained by short-interval scanning, and the need for a better understanding of imaging markers are also described.