Magnetic Resonance Imaging (MRI) has become one of the most important clinical tests used to help diagnose multiple sclerosis (MS). In general, MS is diagnosed when lesions consistent with white matter demyelination are seen on MRI scans and patients exhibit classical symptoms. But MS is not the only disease that can result in demyelinating lesions in the brain. For example, migraine can cause lesions making diagnosis more complicated. When there are both lesions that look like MS and ones that do not, it can be challenging for the radiologist to make a recommendation on diagnosis.
When I was first diagnosed with MS, my local MRI center had a 1.5 Tesla (T) MRI Machine while stronger machines, such as the 3T Machine, were limited to research centers. Now my local MRI center owns a 3T Machine while some research centers are fortunate to have a 7T Machine. What is Tesla (T)? Tesla is the unit of measurement quantifying the strength of a magnetic field. Higher strength in an MRI machine leads to significantly greater detail in images and faster scanning time.
Researchers in Nottingham, UK, have been trying to find a quicker and more accurate way of identifying MS in patients with an unclear diagnosis. To do this they have focused on T2-weighted MRI scans that can show both hyperintense MS lesions and their central veins, which appear hypointense in contrast. Lesions with central veins are called perivenous lesions. In reading your MRI report, you might see reference to periventricular lesions. These are lesions located near cerebral ventricles (a series of interconnected, fluid-filled spaces in the core of the forebrain and brainstem) that are common in MS.
What the researchers have found is that the percentage of lesions that are perivenous can predict whether a patient has MS. Using an ultra-high-field 7T MRI machine for a 2013 study, Mistry et al found that patients for whom more than 40 percent of their lesions had central veins developed MS. Those who had fewer than 40 percent of perivenous lesions did not have MS. This was true for 100 percent of the 29 patients included in the study.
But as mentioned above, 7T MRI machines are hard to come by so researchers wanted to know if using an ultra-high-field 3T MRI machine would yield the same results. The Nottingham University research team has determined that, yes, the presence and percentage of perivenous lesions visualized with optimized T2-weighted scans can predict MS. In a follow-up study involving 40 patients, all patients with MS had central veins in more than 45 percent of brain lesions, while those without MS had central veins visible in less than 45 percent of lesions.
The Nottingham University team has now started a new study examining patients with an uncertain diagnosis and aim to extend the study in other UK towns so more patients can participate in this important research. If this new way of testing for and evaluating MS lesions proves to be accurate, it may make diagnosing MS quicker and more reliable using the tools more readily available in the clinical setting.
See more helpful articles:
Beginner's Guide to MS: What is a Lesion?
Beginner's Guide to MS: How is MS Diagnosed?
What to Do When Newly Diagnosed with MS
Filippi M, Evangelou N, Kangarlu A, et al. Ultra-high-field MR Imaging in Multiple Sclerosis. J Neurol Neurosurg Psychiatry. 2014;85(1):60-66.
Mistry N, Dixon J, Tallantyre E, et al. Central veins in brain lesions visualized with high-field magnetic resonance imaging: a pathologically specific diagnostic biomarker for inflammatory demyelination in the brain. JAMA Neurol. 2013 May;70(5):623-8. doi: 10.1001/jamaneurol.2013.1405.
University of Nottingham, UK. (Feb 1, 2016). New MRI technique offers faster diagnosis of multiple sclerosis press release.