Background

The concept of no evidence of disease activity-3 (absence of brain MRI and clinical disease activity; NEDA-3) in multiple sclerosis (MS) reflects disease activity with limited sensitivity. The added value of neurofilament light chain levels in serum (sNfL) to NEDA-3 has not yet been investigated.

Objectives

To assess whether sNfL allows to identify among patients with and without NEDA-3 status those at higher risk of future disease activity and accelerated brain volume loss.

Methods

We analyzed 369 samples from 155 early relapsing-remitting MS patients (SET study). sNfL levels and brain MRI scans were evaluated annually. The comparison of subgroups defined by high or low sNfL (>90^th or <90^th percentile of healthy controls of the same age) and NEDA-3 status was performed by generalized estimating equation models. Changes in global and regional brain volumes were calculated on three-dimensional T1-weighted scans.

Results

Patients with disease activity (EDA-3) in the preceding year and high sNfL, compared to those with low sNfL, had: a) higher odds of EDA-3 in the following year (87% versus 58%; OR 4.39, 95%-CI:2.18, 8.94; p<0.001), b) greater whole brain volume loss during the following year (0.39%, 95%-CI:-0.63, -0.16; p<0.001) and c) greater whole brain volume loss (0.61%, 95%-CI:-0.66, -0.17; p<0.001) during the preceding year. Accordingly, NEDA-3 patients with high sNfL showed a trend for a return of disease activity (EDA-3) in the following year compared with those with low sNfL (57% versus 31%).

Conclusions

High sNfL levels are associated with increased future risk of disease activity and accelerated brain volume loss. Adding of sNfL improves the prognostic value of the NEDA-3 concept.

Background

Serum neurofilament light chain (sNfL) levels reflect only neuro-axonal injury that took place within 3-6 months prior to the date of sampling. Therefore, the frequency of assessment of sNfL levels for monitoring of disease activity warrants further investigation.

Objectives

To determine differences in accuracy of sNfL levels to detect radiological disease activity during the preceding 6 versus 12 months of follow-up.

Methods

This observational study included 148 patients with early relapsing-remitting multiple sclerosis (MS) from the SET cohort. Based on brain MRI performed at 0, 6 and 12 months, we assessed the ability of categorized sNfL measured at 12 months to reflect the presence of combined unique active lesions, defined as new/enlarging lesion compared with MRI performed in the previous 6 versus 12 months or contrast-enhancing lesion (e.g., active lesions).

Results

Together, 91% (95% CI=85-98%) of patients with ≥1 active lesion during the last 6 months and 84% (95% CI=77-92%) of patients with ≥1 active lesion during the last 12 months had sNfL≥30^th percentile. Among the patients with sNfL<30^th percentile, 14 (33.3%) developed ≥1 active lesion during the last 12 months, but only 6 (14.3%) developed ≥1 active lesion during the last 6 months. Among patients with sNfL<30^th percentile, 6 (14.3%) developed ≥2 active lesions during the last 12 months, but only 2 (4.8%) developed ≥2 active lesions during the last 6 months.

Conclusions

Low levels of sNfL better identified MS patients with the absence of recent radiological disease activity during the previous 6 than the previous 12 months. In the future, assessment of sNfL at least every 6 months may substitute the need for annual brain MRI monitoring to exclude brain lesion activity in clinically stable patients with low sNfL levels.

Background

Regional brain atrophy is a sensitive disability marker for MS patients. A previous study has shown that atrophy of the corpus callosum is an early marker for disease progression. However, the relationship between diffuse pathology in specific brain regions and the course of regional atrophy development remains poorly understood.

Objectives

To investigate quantitative T1 maps and entropy (amount of T1 inhomogeneity) in regional brain structures from diagnostic MRI (performed at disease onset) of MS patients and compare these findings with healthy controls (HC).

Methods

Fifty MS patients and 102 HC were examined on a 3T MRI scanner (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The MRI protocol comprised 3D MP2RAGE, 3D MPRAGE, 3D FLAIR and 3D DIR. The calculation of T1 maps, brain structure segmentations and brain volume measurements were obtained from a single MP2RAGE scan. Lesion segmentation masks were obtained using the LeManPV prototype software (Siemens Healthcare, Erlangen, Germany). We evaluated T1 maps from normal-appearing white matter (excluding lesions) in the corpus callosum, the brain lobes, brainstem and cerebellum, as well as from normal-appearing gray matter (excluding lesions) in the thalami, basal ganglia, and cortical gray matter. We calculated median regional T1 relaxation times, T1 entropy and volume for the above-mentioned structures for the early-MS group and 50 age- and sex-matched HC subjects. Statistical comparison was performed using t-tests.

Results

The median T1 of the corpus callosum in the early MS group was 838 ms (SD 38.5), with entropy 8.42 (SD 0.24); compared to 810 ms (SD 25.2) and 8.23 (SD 0.13) in the HC group. Statistically significant differences were found in T1 times and entropy between the groups (p<0.001); volumes were, however, not statistically different. Smaller but also statistically significant differences in T1 maps and entropy were found for white matter of the brain lobes (p<0.001). Thalami volumes showed statistically significant differences between groups, but not median T1 times (MS group 1055 ms, SD 32.6 vs. HC 1049 ms, SD 21.2).

Conclusions

Pathology of the normal-appearing white matter in T1 relaxometry can already be detected at MS disease onset. In particular, corpus callosum T1 times were considerably higher at clinical onset of MS compared to HC. We hypothesize that early microstructural changes detected at disease onset lead to evolution of regional brain atrophy.

Background

The presence of infratentorial lesions early in the disease has been shown to have prognostic value for future disability in multiple sclerosis (MS). Quantitative imaging metrics such as T1 relaxometry might contribute to understanding the relationship between supratentorial (ST), infratentorial (IT), and spinal cord (SC) pathology.

Objectives

Our aim was to explore the association between ST, IT and SC pathology and microstructural tissue alterations assessed with T1 relaxometry in T2-hyperintense lesions as well as cerebral and cerebellar normal-appearing white matter (NAWM) in patients with recently diagnosed MS with- and without IT lesions.

Methods

Microstructural tissue alterations were assessed in 42 patients (mean age 33.6±8.0 years, median MS duration 0.2 years (0-2.3)) as deviations from normative T1 times, both obtained from the MP2RAGE sequence at 3T (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The normative T1 values were voxel-wise modelled via a study-specific atlas based on spatially normalized data from 102 healthy individuals (21-59 years). Relationship between normalized IT volumes (mesencephalon, pons, medulla oblongata, cerebellum), SC volume, ST and IT lesion loads estimated by the Morphobox prototype, Scanview and LemanPV prototype, respectively and the deviations from normative T1 times expressed as z-score-derived metrics (volumes and means of voxels with z-scores above z-score 2 and below z-score 2) in lesions, cerebral and cerebellar NAWM were studied by partial correlations adjusted for age and brain lesion volume.

Results

Patients with IT lesions (n=23, 33.0±8.5 years) had larger lesion load, higher volumes of voxels with positive z-scores (> 2), higher mean of z-scores above 2 in lesions, and larger thalami than patients without IT lesions (n=19, 34.3±7.7 years). The remaining volumes and z-scores derived metrics did not differ between groups. Cerebellar volume correlated negatively with volume of voxels with negative z-scores (< 2) in cerebellar NAWM (partial correlation coefficient r=-.437, p=.005) only in patients with IT lesions. In patients without IT lesions, SC and pons volumes correlated negatively with volume of voxels with positive z-scores corresponding to areas of supratentorial T2 lesions (SC: r=-.669, p=.003, pons: r=-0.606, p=0.01).

Conclusions

Microstructural alterations identified as T1 z-scores relate differently to IT and SC volumes in MS patients with and without IT lesions. In the presence of IT lesions, changes in cerebellar NAWM (T1 shortening relative to healthy controls) are associated with lower cerebellar volume. In the absence of IT lesions, the association of cerebellar NAWM and cerebellar volume is not present. In patients without IT lesions, microstructural alterations in ST lesions (T1 prolongation) that might indicate the extent of tissue damage in lesions, are associated with lower pontine and SC volumes regardless of the T2 lesion load.

Background

Although conventional MRI acquisitions are of essence in the monitoring of MS, they show low specificity towards the microstructural nature of tissue alterations and exhibit rather low correlations with clinical metrics (“clinico-radiological paradox”). Conversely, recent advances in brain relaxometry allow characterizing microstructural alterations on a single-subject basis; the question yet remains whether such quantitative measurements can help bridging the gap between radiological and clinical findings.

Objectives

This study investigates whether automatically assessed alterations of T₁ relaxation times in brain lesions and normal-appearing white matter (NAWM) improve clinico–radiological correlations in early MS with respect to conventional measures.

Methods

102 healthy controls (65% female, [21-59] y/o) and 50 early-MS patients (76% female, [19-52] y/o) underwent MRI at 3T (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). The employed 3D protocol comprised MPRAGE, FLAIR (both used for lesion segmentation as in [Fartaria et al., 2017, MICCAI]), and MP2RAGE for T₁ mapping.

After the healthy controls’ data were spatially normalized into a study-specific template, reference T₁ values in healthy tissues were established by linear, voxel-wise modelling of the T₁ inter-subject variability [Piredda et al., MRM, 2020]. In the MS cohort, T₁ deviations from the established references were calculated as z-score maps.

Correlations between the EDSS and conventional measures, i.e. lesion volume and count, were compared against correlations with z-score-derived metrics in lesions and NAWM, namely the volume of voxels exceeding a given z-score threshold.

Results

Correlations between EDSS and lesion volume and count were found to be 0.23 and 0.18, respectively. Higher correlations were found between EDSS and the volume of voxels exceeding an absolute z-score threshold of 2, both in lesions and NAWM, with ρ=0.3 and ρ=0.33, respectively. Correlation further improved when considering only negative z-scores, ρ=0.36 for lesions and ρ=0.39 for NAWM. The highest correlation was found when considering absolute z-scores in the occipital lobe NAWM, ρ=0.47.

Conclusions

Microstructural alterations identified as T₁ z-scores were found to improve clinico–radiological correlation in comparison to conventional measures (lesion volume and count). Of notice, negative z-scores (i.e. abnormal T₁ shortening), which may be due to an increase in iron content, appear to be a potential predictor for the clinical state of an early MS patient.