Quite a number of medical specialties require distance and angle measurements on x-ray images. Drafting and measurement on traditional x-ray films can be done with marker pens, rulers and protractor, but this method is time consuming and often inaccurate. Authors present a computer aided drafting and measurement method for both digitized and digital x-rays.

Evaluation of cervical spine x-rays is especially important for patients suffering from rheumatoid arthritis. Our computer program helps users to mark necessary points and draw lines on x-rays interactively on the computer screen, then the program calculates relevant angles and distances based on literature data.

Manual drafting on traditional x-ray films is time consuming, and it is usually impossible or at least difficult to repeat. When one wants to try drafting more than once, previous lines have to be erased from the film, or a separate transparent film can be used. Reading distance and angle values requires a ruler and a protractor. The tip size of the marker pen and the precision of ruler, protractor positioning can result in measurement errors of multiple millimeters and degrees.

Contrarily, computer based drafting allows arbitrary number of users arbitrary number of attempts to define necessary points on x-rays, and then predefined algorithms calculate the results.

Computer aided drafting can be performed by many persons, a number of times. Accuracy can be improved by using image processing capabilities such as zooming, contrast correction, etc. Results can be superimposed on x-ray images, making follow-up easier.

Compared to „traditional” drafting, the computer-aided method’s repeatability and reliability is a great advantage. It is easier to learn computer-based drafting, especially when a large number of points have to be marked and complicated measurements are involved. With an appropriate drafting and evaluation protocol, processing of x-rays provides added diagnostic value, e.g. further examinations can be ordered based on the results, scheduling of follow-ups can be optimized.

DOI: 10.17489/biohun/2013/1/10