How to get each element from a curvelet transform coefficient.

I am new in matlab.I am using curvelab library for curvelet transform in steganography. After applying the fdct_wrapping an image, i have found a co-efficient which a 1*6 cell. (1x1 cell 1x16 cell 1x32 cell 1x32 cell 1x64 cell 1x1 cell). I want to get each of element on the cell individually what should i need to do?

clc;
im1 = imread('Lena.jpg'); % gray image
C = fdct_wrapping(im1,1)

Here, C is the co efficient. Let say i have a threshold value = 7.6338. I need the index where the co eficient has smaller value then the thresholding. I need to save the index.

Thanks

Marzan