MRI in multiple sclerosis

Updates on clinically isolated syndrome and diagnostic criteria for multiple sclerosis

Clinically isolated syndrome (CIS) is a central nervous system demyelinating event isolated in time that is compatible with the possible future development of multiple sclerosis (MS). Early risk stratification for conversion to MS helps with treatment decisions. Magnetic resonance imaging (MRI) is currently the most useful tool to evaluate risk. Cerebrospinal fluid studies and evoked potentials may also be used to assess the likelihood of MS. Four clinical trials evaluating the benefits of either interferon β (IFN-β) or glatiramer acetate (GA) within the first 3 months after a high-risk CIS demonstrate decreased rates of conversion to clinically definite MS (CDMS) and a lesser degree of MRI progression with early treatment. In the 3-, 5-, and 10-year extension studies of 2 formulations of IFN-β, the decreased conversion rate to CDMS remained meaningful when comparing early treatment of CIS to treatment delayed by a median of 2 to 3 years. Diagnostic criteria have been developed based on the clinical and MRI follow-up of large cohorts with CIS and provide guidance on how to utilize clinical activity in combination with radiographic information to diagnose MS. The most recent 2010 McDonald criteria simplify requirements for dissemination in time and space and allow for diagnosis of MS from a baseline brain MRI if there are both silent gadolinium-enhancing lesions and nonenhancing lesions on the same imaging study. The diagnostic criteria for MS require special consideration in children at risk for acute disseminated encephalomyelitis (ADEM), in older adults who may have small vessel ischemic disease, and in ethnic groups that more commonly develop neuromyelitis optica (NMO).

Serum levels of brain-derived neurotrophic factor correlate with the number of T2 MRI lesions in multiple sclerosis

The objective of the present study was to determine if there is a relationship between serum levels of brain-derived neurotrophic factor (BDNF) and the number of T2/fluid-attenuated inversion recovery (T2/FLAIR) lesions in multiple sclerosis (MS). The use of magnetic resonance imaging (MRI) has revolutionized the study of MS. However, MRI has limitations and the use of other biomarkers such as BDNF may be useful for the clinical assessment and the study of the disease. Serum was obtained from 28 MS patients, 18-50 years old (median 38), 21 women, 0.5-10 years (median 5) of disease duration, EDSS 1-4 (median 1.5) and 28 healthy controls, 19-49 years old (median 33), 19 women. BDNF levels were measured by ELISA. T1, T2/FLAIR and gadolinium-enhanced lesions were measured by a trained radiologist. BDNF was reduced in MS patients (median [range] pg/mL; 1160 [352.6-2640]) compared to healthy controls (1640 [632.4-4268]; P = 0.03, Mann-Whitney test) and was negatively correlated (Spearman correlation test, r = -0.41; P = 0.02) with T2/FLAIR (11-81 lesions, median 42). We found that serum BDNF levels were inversely correlated with the number of T2/FLAIR lesions in patients with MS. BDNF may be a promising biomarker of MS.

In vivo quantitative evaluation of brain tissue damage in multiple sclerosis using gradient echo plural contrast imaging technique

Conventional MRI based on weighted spin-echo (SE) images aids in the diagnosis of multiple sclerosis (MS); however, MRI markers derived from SE sequences provide limited information about lesion severity and correlate poorly with patient disability assessed with clinical tests. In this study, we introduced a novel method [based on quantitative R2* (1/T2*) histograms] for estimating the severity of brain tissue damage in MS lesions. We applied at 1.5T an advanced, multi-gradient echo MRI technique [gradient echo plural contrast imaging (GEPCI)] to obtain images of the brains of healthy control subjects and subjects with MS. GEPCI is a simple yet robust technique allowing simultaneous acquisition of inherently co-registered quantitative T2* and FLAIR-like maps, along with T1-weighted images within a clinically acceptable time frame. Images obtained with GEPCI appear highly similar to standard scans; hence, they can be used in a reliable and conventional way for a clinical evaluation of the disease. Yet, the main advantage of GEPCI approach is its quantitative nature. Analysis of R2* histograms of white matter revealed a difference in the distribution between healthy subjects and subjects with MS. Based on this difference, we developed a new method for grading the severity of tissue damage [tissue damage score (TDS)] in MS lesions. This method also provides a tissue damage load (TDL) assessing both lesion load and lesion severity, and a mean tissue damage score (MTDS) estimating the average MS lesion damage. We found promising correlations between the results derived from this method and the standard measure of clinical disability.