Thank you for replies. I am a modest cardiologist; although with some coding experience (in matlab for example), scripting in an environment unfamiliar would be something that would take a long time. For the community-wide MRI cardiologists there will be a very high utility for a tool at a very acceptable price - such as Illustrator, to load images and also to trace automatically  the contour at the border between the blood (usually shows up as white) and the heart muscle or myocardium (shows as dark). I would be interested to partner with a person interested to develop these tools. I assume they will be useful for other purposes other than cardiac MR. At any rate, the latter one taken alone can be substantial, since this is an emerging technique with many advantages in comparison with the classical echocardiogram. Please let me know. Again, I appreciate the help.

I played a little with live trace in CS5. Seems to do quite a good job if I had the right contrast between the blood (white stuff) and the myocardium (the dark circular wall surrounding the white round area). Picture one is the contrasted picture taken off a dicom medium (these media allow adjusting the contrast very well). Left ventricle is the smiley face on the right of image. The right ventricle is on the left, kind of D shaped. The second picture is the live trace image (with "make and expand" selection). I selected the image with the "direct selection tool (A)", then used the live trace with make and expand. The tracing can not be seen here, but it is very accurate.

The third image is the same MRI image as in picture one without contrast adjustment. Live trace did bad - fourth picture.