Pixels^4 to mm^4


I used BoneJ’s slice geometry feature and computed I min and I max (second moment of inertia). I need help to convert pixels^4 to mm^4 from the results output, given my pixel resolution from my CT scans was 18 micronmenter or (0.018 mm)? Can someone please help me with that? Furthermore, does BoneJ return units of mm as opposed to pixels?



Yes, if the image’s spatial calibration is set (Image>Properties). The units are reported in the column headers of the Results table, here mm4:

If your images are not calibrated, the easiest thing to do is to calibrate them in Image>Properties and run the analysis again. Alternatively, multiply all your I values by (mm/pixel)4, which in your case is 0.0184 = 0.000000105 mm4/pixels4.