Recent data are suggestive of a predictive value of imaging techniques for early detection of antiangiogenic treatment efficacy in different cancers. To our knowledge there are no presented data available on correlation between changes in diffusion-weighted MR and response to bevacizumab treatment in lung cancer. The current study is designed as a pilot study to prospectively investigate changes in MR variables during treatment with bevacizumab and to detect signals of prognostic and/or predictive value of MR changes during treatment.