MS Diagnosis
How do doctors make the multiple sclerosis diagnosis? In the past, doctors used lumbar puncture findings, which weren’t specific for the disease, but were highly suggestive, to confirm a clinical picture of someone with several relapses and remissions of neurological symptoms, and make the multiple sclerosis diagnosis. In a lumbar puncture, a fine needle is inserted into the lower back between two vertebrae, into the area surrounding the spinal cord. From here, cerebrospinal fluid (CSF) is withdrawn and analysed to determine its composition. Even when CT (computerised tomography) scans became available in the 1980s, the lesions of MS were too small to be seen, and this test couldn’t be used to help make the MS diagnosis.
The diagnostic breakthrough came with the development of MRI (magnetic resonance imaging) scanning. MRI is an imaging method which, unlike CT, doesn’t use X-rays or other forms of radiation. It uses magnets and sensors to detect minute magnetic fields within cells. It can be used again and again without any radiation risk to the patient. For some people, it is however extremely claustrophobic being inside one of these machines. It is possible though to ask for a short-acting sedative to make these scans more tolerable. The scans enable us to see tiny defects in the CNS. The lesions of MS usually show up even if they are very small, although some don’t. MRI shows lesions in 95 per cent of people with clinically definite MS1 but it isn’t definitive. Some other diseases produce lesions that look like MS on MRI. It needs to be used in conjunction with the doctor’s clinical diagnosis, that is assessment of symptoms, as well as findings on clinical examination, before a diagnosis of MS can be made.
The diagnostic breakthrough came with the development of MRI (magnetic resonance imaging) scanning. MRI is an imaging method which, unlike CT, doesn’t use X-rays or other forms of radiation. It uses magnets and sensors to detect minute magnetic fields within cells. It can be used again and again without any radiation risk to the patient. For some people, it is however extremely claustrophobic being inside one of these machines. It is possible though to ask for a short-acting sedative to make these scans more tolerable. The scans enable us to see tiny defects in the CNS. The lesions of MS usually show up even if they are very small, although some don’t. MRI shows lesions in 95 per cent of people with clinically definite MS1 but it isn’t definitive. Some other diseases produce lesions that look like MS on MRI. It needs to be used in conjunction with the doctor’s clinical diagnosis, that is assessment of symptoms, as well as findings on clinical examination, before a diagnosis of MS can be made.
The MRI breakthrough has led to much more sophisticated clinical trials of therapies for MS. Now, with MRI, we can monitor the development of new lesions, rather than relying on the not so accurate clinical picture of signs and symptoms as assessed by a doctor. This is particularly important given that most of the damage that is occurring can’t be detected by clinical examination by the doctor. In turn though, this has created its own problems. We may show that a particular therapy decreases the number of new lesions, yet see no difference in the person clinically. This occurred with many of the drug studies. At least with earlier studies, we were using the patient as the yardstick, not what the scan looked like.
Nevertheless, large studies correlating MRI findings with clinical course have now shown that people with MS have significant atrophy (shrinkage) of both white and grey matter in the brain.2 Secondary progressive patients have more atrophy than relapsing-remitting patients and a higher lesion load. Lesion load and atrophy in this study significantly predicted EDSS score, and grey matter atrophy was the most significant MRI predictor of final disability.
The advent of MRI, although making the diagnosis of MS easier, paradoxically has caused some difficulties. Multiple sclerosis is two or more attacks of scarring in the CNS. It is, by definition, multiple. Previously, people might have had one episode of neurological disturbance, and the doctor may have thought ‘This might be MS’ but had to wait until a second attack to be more certain. With MRI, we can see the typical lesion often on the first attack. Because it is an isolated lesion, the doctor may call it ‘transverse myelitis’ if it is in the spinal cord, or some other term. With the MRI though it is now often possible to see evidence of other lesions which perhaps didn’t cause any symptoms, thus providing some evidence that the disease is ‘multiple’. It is important for people who believe they may have multiple sclerosis symptoms to seek a diagnosis from their doctor.
Back to Top
Nevertheless, large studies correlating MRI findings with clinical course have now shown that people with MS have significant atrophy (shrinkage) of both white and grey matter in the brain.2 Secondary progressive patients have more atrophy than relapsing-remitting patients and a higher lesion load. Lesion load and atrophy in this study significantly predicted EDSS score, and grey matter atrophy was the most significant MRI predictor of final disability.
The advent of MRI, although making the diagnosis of MS easier, paradoxically has caused some difficulties. Multiple sclerosis is two or more attacks of scarring in the CNS. It is, by definition, multiple. Previously, people might have had one episode of neurological disturbance, and the doctor may have thought ‘This might be MS’ but had to wait until a second attack to be more certain. With MRI, we can see the typical lesion often on the first attack. Because it is an isolated lesion, the doctor may call it ‘transverse myelitis’ if it is in the spinal cord, or some other term. With the MRI though it is now often possible to see evidence of other lesions which perhaps didn’t cause any symptoms, thus providing some evidence that the disease is ‘multiple’. It is important for people who believe they may have multiple sclerosis symptoms to seek a diagnosis from their doctor.
- Paty DW, Oger JJF, Kastrukoff LF, et al. Magnetic resonance imaging in the diagnosis of multiple sclerosis (MS): a prospective study of comparison with clinical evaluation, evoked potentials, oligoclonal banding, and CT. Neurology 1988; 38:180-185.
- Tedeschi G, Lavorgna L, Russo P, et al. Brain atrophy and lesion load in a large population of patients with multiple sclerosis. Neurology 2005; 65:280-285
- Paty DW, Oger JJF, Kastrukoff LF, et al. Magnetic resonance imaging in the diagnosis of multiple sclerosis (MS): a prospective study of comparison with clinical evaluation, evoked potentials, oligoclonal banding, and CT. Neurology 1988; 38:180-185.
- Tedeschi G, Lavorgna L, Russo P, et al. Brain atrophy and lesion load in a large population of patients with multiple sclerosis. Neurology 2005; 65:280-285