Assessment of the functional diffusion map (fDM) as an imaging biomarker for early stratification of glioma clinical response

1518 Background: Current assessment of glioma treatment response relies on changes in the product of the maximal perpendicular tumor diameters at 2 months following treatment. Due to the fact that patients with malignant glioma have high mortality rates and a short median survival (about 41 weeks), the ability to stratify these tumors into responsive and non-responsive categories prior to treatment completion would allow for individualization of treatment. Changes in glioma water diffusion values were quantified using diffusion MRI as a biomarker for therapeutic-induced changes in tumor cellularity. Methods: A total of 37 patients with Grade III/IV supratentorial malignant gliomas (restricted to anaplastic astrocytomas (Grade III) and glioblastomas/sarcomas (Grade IV)) into a clinical imaging study. Standard and diffusion MRI scans pre-treatment and at 3 weeks post-initiation of chemo- and/or radio-therapy were acquired. Images were co-registered to pretreatment scans, and changes in tumor water diffusion values were calculated and displayed as a functional diffusion map (fDM) for correlation with clinical response. Results: Analysis of the patient data revealed that the fDM volumes of total detected diffusion change (VT) was able to statistically discriminate (P [Table: see text]