1 What does magnetic resonance imaging (MRI) tell physicians about multiple sclerosis (MS)?  While everyone acknowledges that MRI has greatly improved clinicians’ ability to diagnose MS, there is great interest in using MRI for other purposes, such as evaluating the effectiveness of potential treatments, determining the relationship between symptoms like depression and MS lesions, and predicting the course of disease. Determining how to use MRI to do these things is the subject of considerable research and discussion. What is MRI?  Magnetic resonance imaging is a way of taking pictures of the inside of the body.  Unlike x-rays, MRI scans do not require the use of ionizing radiation.  Instead, a strong magnetic field and electromagnetic pulses are applied to the body.  Protons, the charged core of water molecules’ hydrogen atoms, are aligned by the magnetic field, just as iron filings can be aligned by a much smaller magnet.  By manipulating the alignment of the protons with electromagnetic pulses, the protons can be made to give off signals that are assembled into two-dimensional image “slices” using sophisticated software. Three-dimensional images can be generated by adding these slices together. The results are high quality images that can give a very good picture of water- containing structures inside the body. In people with MS, clinicians want to take pictures of the damaged areas of the nervous system that are characteristic of the disease.  In MS, the fatty sheath called myelin that surrounds nerve fibers is damaged and also sometimes destroyed in patches that are called lesions.  The nerve fibers themselves are sometimes destroyed as well.  MRI can be used to take pictures that show these lesions, and different kinds of MRI images show different features of these damaged areas. When a lesion is new or enlarging, there is usually a lot of swelling and inflammation associated with it.  The barrier between the blood and the brain breaks down, and white cells migrate into the area surrounding the lesion. These areas of inflammation are best seen with a kind of image called a “T2-weighted” image or by using a so-called “T1-weighted” image, which is Magnetic Resonance Imaging and MS Depression in MS Transient Symptoms in MS NARCOMS News Breaking News Overview of How a Drug Is Developed Current Clinical Trials in MS CMSC/NARCOMS Information Corner Index to MSQR Volumes 18–20 Volume 20, Number 4,Winter 2001 MULTIPLE SCLEROSIS QUARTERLY REPORT Magnetic Resonance Imaging and Multiple Sclerosis: What Does It Tell Us? Charles R. G. Guttmann, MD, Director, Center for Neurological Imaging, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA A joint publication of Eastern Paralyzed Veterans Association and the CMSC/North American Research Committee on MS INSIDE: 6 10 17 23 North American Research Committee on MS 1 continued on page 3 Consortium of Multiple Sclerosis Centers 13 21 32 33