Use of textural analysis of tumour vascular heterogeneity as a biomarker of response to anti-angiogenic treatment in patients with nasopharyngeal carcinoma

Materials and methods DCE-CT images of 33 patients, with recurrent/metastatic NPC treated with pazopanib, were analyzed to derive tumour blood flow, fractional intravascular blood volume, fractional extracellular-extravascular volume, and permeability surface area product. To each parametric map, textural analysis using multiple parameters based on co-occurrence matrix, neighbourhood gray tone difference, run-length matrix, gray level size-zone matrix and histogram statistics were applied to characterize its heterogeneity. Reproducible and important textures, were selected by a cut-off on the coefficient of variation and variable importance determined by random forest analysis, respectively. These textures are summarized by principal components analysis and their relationship to outcomes evaluated using Cox proportional hazards, receiver-operating characteristics, Kaplan-Meier and logistics regression analysis.