extract vessels from x-ray

Hello,

I would like to extract the blood vessels and arteries from the attached picture.

I tried some different methods, but the result is not so good.

How can I solve my problem?

[Star Strider]

First, inject an iodinated contrast medium to make the vessels visible. It is almost impossible to delineate blood vessels in a normal radiograph. (There are other factors to consider, most significantly renal toxicity, in using these agents.)

[Mihai Nichita]

Thank you for suggestions, but is there any tool or software technique that I can use to increase the vessels' gray level? I have already tried few, but the result was not the desired one.

[Star Strider]

My pleasure. I doubt that one exists. Iodinated contrast agents are even necessary to accurately delineate blood vessels in CT radiographs.