texture order

hello i do volume rendering via 3d texture.i make the 3d texture[][][][] to be texture[r][t][s][4]using slices of CT image. r corresponds to slice numbers of image,t is height of image,s is width of image. does the order of r,t,s right?i found when rotate the texture along Y,Z axis is right ,but rotate along the X axis the direction reverse.what is the problem?