JACK SIMON, MD, PhD: Most MRI acquisitions are site-specific. We all do the examination a different way. And so it's difficult to compare from center to center, and even from time A to time B in any one center, the findings. So the attempt is to standardize the MRI examination which would allow us to provide a more objective, quantitative measure of disease at any one time and change in disease over time.

The guidelines are fairly simple. And they call for standardized acquisition, standardized thickness, for example 3 millimeter-thick slices without gaps, and acquiring the images in standardized planes, for example from the front to the back of the corpus callosum -- so that a patient can have a study at one center and have the same study at another center at a different point in time.

In addition, the attempt is to standardize in the types of acquisition, for example proton density and T2 axial series as well as flare axial series and a contrast enhanced series to follow.