From: Tan on
fpath = '......hdr'
>> info = analyze75info (fpath);
>> vol = analyze75read (info);

ColorType: 'grayscale'
ByteOrder: 'ieee-le'
HdrDataType: 'UINT16'
Dimensions: [512 512 64 1]

>> slc = vol(:, :, 35);
histgram = imadjust(slc);
>> figure; imhist(histgram);

this is the histogram which i can get from a 16bit image..

sorry i'm very new to matlab..