$$$ for help! - measuring radius of curvature on MRI - help needed from hand surgeon who knows nothing about code - willing to pay $$$

I have a set of MRI scans, and am trying to measure the radius of curvature of certain bones.

I have figured out how to manually plot points along the edge of the bone, and then use Image J to fit a circle to these points.

However, when I have the program measure the circle, I do not understand what units the measurements are in. I require measurements in mm or cm.

Please reply if you can help. I am willing to provide compensation for anyone who can walk me through the process.

Thank you!


So… the measurements in the Results table will be reported in whatever units your images are using. You can check what units are applied to your particular images if you look at the top bar of your image window… for example, the first image is in microns and the second in pixels:


You can set the scale of your images if you need using Set Scale… You can just check the image Properties as well to be sure the units that are being used in your images.

Hope this helps!

eta :slight_smile:


Thank you so much for your response. Perhaps I am doing this wrong.

  1. I am using the “multi-point” tool to place points on an image.
  2. Then, I go to Edit --> Fit Circle. A circle is then placed on my image using the points I plotted.
  3. Then, I got to Ananlyze --> Measure. Below is the screen that pops up after I click Measure. As you see, there are no units specified.

What am I doing wrong?


You aren’t doing anything wrong… as @anon96376101 and I both said…

That is step one! :slight_smile: Just report back once you’ve checked…


thank you guys so much.

Ive uploaded pictures of the resolution numbers at the top, my fitted circle, and the results. If you could show me how to use the first numbers to interpret the measurements, I’d be very appreciative!

Your units are in microns, so the results are in those units. You can look at the Set Measurements list to see how each result is calculated… but you’ve got it from here-on-out. We’ve set you up with all the links (here and above) and info you need to figure the rest of your analysis out regarding this issue… you can do it!


I fully agree with Ellen:

Nothing wrong, your are done:
The diameter of the fitting circle is 39843.7µm, i.e. about 39.8mm.

Does that help?


The “Width” and “Height” are the bounding box dimensions of your ROI. "Major"and “Minor” show the measurement of the “Fit ellipse”.

In your result table, the “Width”, “Height”, “Major” and “Minor” are very similar ~39.8mm.

Eta and Herbie, please send me your venmo account for a small token of appreciation!