Pixel to mm conversion

Hi everyone.

I have a dicom image(CT image). the dimention of the file is(512*512*300). I want to change the scale of it to mm. I know the the pixel spacing in x and y are (0.78*0.78), and in z is (2.5 mm). Can you help me with that?

Answer 1

[Walter Roberson]

If what you want out is a cuboid with pixels that are 1mm x 1mm x 1mm then

Use imresize3 with the new size 512*0.78 by 512*0.78 by 300*2.5

[Poorya]

thank you for your suggestion. I tried imresize, but I did not get the good result. when I used it, it change the dimention(400*400*750) not the value.

X = imresize3(I1,[512*0.78 512*0.78 300*2.5]);

is it right?

[Walter Roberson]

Yes, that should be fine. Each voxel in X will now be 1mm by 1mm by 1mm

512 pixels * 0.78 mm per pixel = 400 mm, and you are getting out an array that is 400 (new) pixels, so that would be 400 mm / 400 pixels = 1 mm per pixel.