Hello, Tim, Thanks very much for your answer. Yes. it is very helpful. I can run the DTIFIT now and all of slices were processed. However, each created tensor map is all like a mask. For example, the values of FA in the brain are all ones. Maybe the bvals and bvecs files I created are incorrect? Here is the content of my bvals file 0.0 1000.0 1000.0 1000.0 1000.0 1000.0 1000.0 Here is the content of my bvecs file 0.0 0.70711 -0.70711 0.0 0.0 0.70711 -0.70711 0.0 0 0.0 0.70711 0.70711 0.70711 0.70711 0.0 0.70711 0.70711 0.70711 -0.70711 0.0 0.0 I ran the bedpost_datacheck and everything seems OK. Whatelse can I check? Best, LC