The most important way to follow a patient with multiple sclerosis and to make the diagnosis of multiple sclerosis is with a careful history and examination. Laboratory tests can be useful in the setting of confirming the disease, measuring disease burden, and explaining unusual findings in a particular patient.

The most useful test at this time to confirm the diagnosis of multiple sclerosis and to get a sense of the burden of disease is the MRI of the brain or magnetic resonance imaging. MRI works for brain tissues because of the high percentage of water in the various brain compartments and the varying degree of movement that they have. Since water is an electrical dipole, when placed in a magnetic field, they line up along the magnetic field. Radio waves are then used to push these molecules sideways and their return to their prior position is detected. Settings on the machine can be varied which allows one to look at the brain on various planes and to bring out different characteristics. Each series of pictures of the brain is called a sequence and a combination of sequences are performed at each MRI setting. Most commonly a contrasting agent called gadolinium or Gad is used to highlight areas where the blood brain barrier is actively disrupted. In drug studies, MRI are frequently performed to supply additional information that is not particularly needed in the treatment of an individual patient. Over time, brain atrophy is a very useful measure but one which is not readily accessible at this time in a general clinical setting.

A lumbar puncture, or spinal tap, is the procedure used to obtain fluid that is around the spinal cord. This fluid is made in the ventricles of the brain and circulates through the brain and then some of it goes around the spinal cord. The tests performed on the spinal fluid look for evidence of an inflammatory response in the central nervous system of the type typically seen in MS. These tests are called the IgG index, IgG synthesis rate, and the presence or absence of oligoclonal bands. Other CNS infections and inflammatory diseases can make these tests abnormal but it is a very useful test in the clinical setting if trying to decide if one has MS or not. It is not a useful test at this time to follow patients along. The lumbar puncture can be performed either in a typical patient examination room or with fluoroscopic guidance in a radiology suite. Patients of mine who have had both procedures generally prefer the one performed in a regular exam room. The only frequent side effects of a lumbar puncture or spinal tap is local back pain for a day or two and a post-spinal headache. There are two different type of needles that can be used. Atraumatic needles cause fewer post spinal tap headaches and are therefore preferred to the more frequently used quickie® needles. The atraumatic needles are relatively newer and have not yet made it into widespread use.

Evoked potentials, and particularly visual evoked potentials are useful tests in the diagnosis of MS. For reasons that are not clear, the small portion of the optic nerve between the eye and where the 2 optic nerves join at what is called the chiasm is frequently affected in MS. Because even a healed MS lesion in this area causes slowing of nerve conduction, the visual evoked potential or visual evoked response is a very useful test. In this test, the patient looks at a checkerboard pattern which alternates the black and white squares. The time is takes for the pattern to change to the change of the EEG over the occipital lobe of the brain (where the pattern is transmitted) is measured. If one eye is substantially slower than the other eye, then there must be a problem with the eye, the retina, or the optic nerve itself. An eye exam can rule out difficulty in the eye and retina leaving the problem in the optic nerve. In the proper clinical setting, it therefore becomes a very useful test. Similar evoked potentials or evoked responses can be performed with hearing and on the nerves on the arms and legs but are not nearly as useful.

Hopefully in the future a blood test for MS can be developed from the current research going on with Tcell vaccination.