Convert mean roi CT Data to Hounsfield Units

[Giorgio Cadoro]

Hi all,
i have the stacks of dicom images with depht of 16bit.I'm looking to
convert the mean value of a roi in hounsfield unit and not in pixel
value.
These  values in miscellaneous stacks are always:Intercept=0 and
Slopes=1 and i don't think that i can use them with this equation(hu =
pixel_value * slope + intercept)
  50 : (0028,1052) : DS : IMG Rescale Intercept : 6 : 0
  51 : (0028,1053) : DS : IMG Rescale Slope : 2 : 1
Are there other ways?
Thanks ..
Cadoro Giorgio