Performance of five research-domain automated WM lesion segmentation methods in a multi-center MS study

BACKGROUND AND PURPOSE

In vivoidentification of white matter lesions plays a key-role in evaluation of patients with multiple sclerosis (MS). Automated lesion segmentation methods have been developed to substitute manual outlining, but evidence of their performance in multi-center investigations is lacking. In this work, five research-domain automated segmentation methods were evaluated using a multi-center MS dataset.

METHODS

70 MS patients (median EDSS of 2.0 [range 0.0-6.5]) were included from a six-center dataset of the MAGNIMS Study Group (www.magnims.eu) which included 2D FLAIR and 3D T1 images with manual lesion segmentation as a reference. Automated lesion segmentations were produced using five algorithms: Cascade; Lesion Segmentation Toolbox (LST) with both the Lesion growth algorithm (LGA) and the Lesion prediction algorithm (LPA); Lesion-Topology preserving Anatomical Segmentation (Lesion-TOADS); and k-Nearest Neighbor with Tissue Type Priors (kNN-TTP). Main software parameters were optimized using a training set (N = 18), and formal testing was performed on the remaining patients (N = 52). To evaluate volumetric agreement with the reference segmentations, intraclass correlation coefficient (ICC) as well as mean difference in lesion volumes between the automated and reference segmentations were calculated. The Similarity Index (SI), False Positive (FP) volumes and False Negative (FN) volumes were used to examine spatial agreement. All analyses were repeated using a leave-one-center-out design to exclude the center of interest from the training phase to evaluate the performance of the method on 'unseen' center.

RESULTS

Compared to the reference mean lesion volume (4.85 ± 7.29 mL), the methods displayed a mean difference of 1.60 ± 4.83 (Cascade), 2.31 ± 7.66 (LGA), 0.44 ± 4.68 (LPA), 1.76 ± 4.17 (Lesion-TOADS) and -1.39 ± 4.10 mL (kNN-TTP). The ICCs were 0.755, 0.713, 0.851, 0.806 and 0.723, respectively. Spatial agreement with reference segmentations was higher for LPA (SI = 0.37 ± 0.23), Lesion-TOADS (SI = 0.35 ± 0.18) and kNN-TTP (SI = 0.44 ± 0.14) than for Cascade (SI = 0.26 ± 0.17) or LGA (SI = 0.31 ± 0.23). All methods showed highly similar results when used on data from a center not used in software parameter optimization.

CONCLUSION

The performance of the methods in this multi-center MS dataset was moderate, but appeared to be robust even with new datasets from centers not included in training the automated methods.

Cumulative Dose of Macrocyclic Gadolinium-Based Contrast Agent Improves Detection of Enhancing Lesions in Patients with Multiple Sclerosis

BACKGROUND AND PURPOSE

Gadolinium-enhanced MR imaging is currently the reference standard for detecting active inflammatory lesions in patients with multiple sclerosis. The sensitivity of MR imaging for this purpose may vary according to the physicochemical characteristics of the contrast agent used and the acquisition strategy. The purpose of this study was to compare detection of gadolinium-enhancing lesions or active disease following a single or cumulative dose of a macrocyclic gadolinium-based contrast agent with different image acquisition delays in patients with clinically isolated syndrome or relapsing multiple sclerosis.

MATERIALS AND METHODS

All patients received a first dose (0.1 mmol/kg) of gadobutrol and, 20 minutes later, a second dose (0.1 mmol/kg), with a cumulative dose of 0.2 mmol/kg. Two contrast-enhanced T1-weighted sequences were performed at 5 and 15 minutes after the first contrast administration, and 2 additional T1-weighted sequences at 5 and 15 minutes after the second contrast administration with a 3T magnet.

RESULTS

One hundred fifteen patients were considered evaluable. A significantly larger number of lesions were detected in scans obtained at 5 and 15 minutes after the second contrast injection compared with scans obtained at 5 and 15 minutes after the first injection (P < .001). The number of patients with active lesions on MR imaging was significantly higher after the second dose administration (52.0%, first dose versus 59.2%, second dose; P < .001).

CONCLUSIONS

Cumulative dosing of a macrocyclic gadolinium-based contrast agent increases detection of enhancing lesions and patients with active lesions. These data could be considered in the design of MR imaging protocols aimed at detecting active multiple sclerosis lesions.

Varicella-zoster meningovasculitis in a multiple sclerosis patient treated with natalizumab

Background:

Natalizumab is associated with the occasional occurrence of progressive multifocal leukoencephalopathy (PML). While natalizumab-associated PML is well described in multiple sclerosis (MS) patients, herpes and other infections have rarely been reported.

Objective:

To report a case of varicella-zoster (VZV) meningovasculitis in a MS patient treated with natalizumab.

Methods:

Case report.

Results:

A 48-year-old woman diagnosed with MS in treatment with natalizumab (Expanded Disability Status Scale (EDSS): 4.0). After 72 infusions, she complained of a holocraneal headache and a new unsteady gait with diplopia (EDSS: 5.0). A brain and spinal cord magnetic resonance (MR) scan showed a multifocal leptomeningeal enhancing nodular lesions and an angiography revealed irregularity of the proximal segments of cerebral arteries. Testing for VZV DNA by polymerase chain reaction (PCR) amplification was positive in cerebrospinal fluid. Treatment with endovenous acyclovir was started. After clinical improvement (EDSS: 4.5), treatment with natalizumab was restarted associated with oral acyclovir as prophylaxis.

Conclusion:

Neurologists should be aware of other possible neuroinfections besides PML in MS patients under natalizumab.

Brain networks associated with cognitive and hedonic responses to a meal

BACKGROUND

We recently reported interrelated digestive, cognitive, and hedonic responses to a meal. The aim of this study was to identify brain networks related to the hedonic response to eating.

METHODS

Thirty-eight healthy subjects (20-38 age range) were evaluated after a 5-hour fast and after ingestion of a test meal (juice and warm ham and cheese sandwich, 300 mL, 425 kcal). Perceptual and affective responses (satiety, abdominal fullness, digestive well-being, and positive mood), and resting scans of the brain using functional MRI (3T Trio, Siemens, Germany) were evaluated immediately before and after the test meal. A high-order group independent component analysis was performed to investigate ingestion-related changes in the intrinsic connectivity of brain networks, with a focus on thalamic and insular networks.

KEY RESULTS

Ingestion induced satiation (3.3±0.4 score increase; P<.001) and abdominal fullness (2.4±0.3 score increase; P<.001). These sensations included an affective dimension involving digestive well-being (2.8±0.3 score increase; P<.001) and positive mood (1.8±0.2 score increase; P<.001). In general, thalamo-cortical connectivity increased with meal ingestion while insular-cortical connectivity mainly decreased. Furthermore, larger meal-induced changes (increase/decrease) in specific thalamic connections were associated with smaller changes in satiety/fullness. In contrast, a larger meal-induced decrease in insular-anterior cingulate cortex connectivity was associated with increased satiety, fullness, and digestive well-being.

CONCLUSIONS AND INFERENCES

Perceptual and emotional responses to food intake are related to brain connectivity in defined functional networks. Brain imaging may provide objective biomarkers of subjective effects of meal ingestion.

Brain atrophy 15 years after CIS: Baseline and follow-up clinico-radiological correlations

BACKGROUND

Brain atrophy in multiple sclerosis (MS) patients is present since the very early stages of the disease and it has been related to long-term disability.

OBJECTIVE

To estimate brain volume (BV) at 15 years after a clinically isolated syndrome (CIS) and to evaluate its relationship with disease outcomes.

METHODS

From a prospective cohort including patients presenting with a CIS, 54 patients with a brain magnetic resonance imaging (MRI) performed 15 years after CIS were included. Brain parenchymal fraction (BPF), grey matter fraction (GMF) and white matter fraction (WMF) at 15-year follow-up were obtained. Regression analyses were conducted to predict BV loss and reaching an Expanded Disability Status Scale (EDSS) of 3.0 in that 15-year period.

RESULTS

In multivariable analyses, lower values of BPF and WMF were significantly associated with being male, presenting 3-4 Barkhof criteria at baseline, presenting a second relapse, and with a decision to start treatment. In the multivariable logistic regression analysis, only lower GMF was associated with a greater risk of reaching EDSS 3.0 (odds ratio (OR) = 0.24, p = 0.028).

CONCLUSION

Lower BPF and WMF 15 years after CIS are associated with previous markers of inflammatory disease. Lower GMF 15 years after a CIS is associated with an increased risk of reaching an EDSS of 3.0.

Infection dynamics of Mycoplasma hyorhinis in three commercial pig populations

Mycoplasma hyorhinis is one of the causative agents of polyserositis and arthritis in postweaning pigs. Knowledge regarding colonisation frequency and age distribution in modern pig production is lacking. The objective of this study was to estimate the prevalence of M hyorhinis colonisation in different age groups across three commercial pig populations. Nasal swabs were collected from sows, piglets and nursery pigs of different ages. Oral fluids were collected from nursery pigs. Necropsies were performed to assess the presence of M hyorhinis-associated disease. M hyorhinis was detected in 5/60 sows in herd A, 3/60 in herd B and none in herd C. In herd A and B, the prevalence was low in preweaning piglets (∼8 per cent) and high in postweaning pigs (∼98 per cent). A total of 7/8 oral fluids tested PCR positive in herds A and B, while 1/8 tested positive in herd C. In herd C, the preweaning and postweaning prevalence was low. In herds A and B, necropsied pigs had polyserositis lesions where M hyorhinis was detected by PCR. This study showed that prevalence of M hyorhinis colonisation varies with pig age and across farms. Information generated will aid in the design and implementation of control and prevention strategies.

Spinal cord lesions: A modest contributor to diagnosis in clinically isolated syndromes but a relevant prognostic factor

Background:

The usefulness of performing a spinal cord (SC) magnetic resonance imaging (MRI) in all clinically isolated syndromes (CIS) is controversial.

Objective:

To assess the value of SC lesions for predicting multiple sclerosis (MS) diagnosis and disability accrual in CIS.

Methods:

Concerning SC lesions and MS diagnosis (2010 McDonald), adjusted Cox regression analyses were performed in increasingly specific CIS groups: all cases ( n = 207), non-SC CIS ( n = 143), non-SC CIS with abnormal brain MRI ( n = 90) and non-SC CIS with abnormal brain MRI not fulfilling 2010 MS ( n = 67). For the outcome Expanded Disability Status Scale (EDSS) ≥3.0, similar analyses were performed in all cases ( n = 207), non-SC CIS ( n = 143) and SC CIS ( n = 64). Performance at 2 years was assessed for all outcomes.

Results:

The presence of SC lesions increased MS risk 2.0–2.6 times independently of factors like brain lesions. If considering lesion number, the risk ranged from 1.6 to 2.1 for one lesion to 2.4–3.3 for ≥2. SC lesions increased the short-term disability risk around fivefold, better demonstrated in non-SC CIS. SC lesions were very specific for evolution to MS and showed very high sensitivity for EDSS ≥3.0.

Conclusion:

SC lesions are independent predictors of MS in all CIS and contribute to short-term disability accrual. SC MRIs in CIS could be useful to estimate their prognosis.

[Magnetic resonance imaging with gadolinium in the acute phase of relapses in multiple sclerosis]

AIM

To describe the factors that are associated with gadolinium enhancement on MRI in patients with multiple sclerosis (MS) and symptoms of relapse.

PATIENTS AND METHODS

A retrospective cross-sectional study of patients over 18 years diagnosed with relapsing-remitting MS, secondary progressive and primary progressive from 2009 to 2014, who had a clinical relapse and underwent brain and spinal resonance with gadolinium during the acute phase of the symptoms.

RESULTS

Of the 93 patients enrolled, 70% were women, the average age was 37 ± 9.6 years. 90% had relapsing-remitting MS and 50% had at least 5 years since the diagnosis. The 56% had medullar involvement, being the most frequent sensory disturbances (44%). The median duration of symptoms was 6 days (range: 1-89 days). The 93% required treatment with intravenous methylprednisolone 3-5 days, which was administered after performing MRI studies. No evidence statistical difference in the presence of lesions that gadolinium enhancement on MRI during relapse with any of the clinical variables analyzed and only a tendency was observed with associated symptoms (p = 0.07).

CONCLUSIONS

The definition of relapse MS is clinic. However, the enhancement of the MRI in the phase of relapse could be useful to confirm the disease's activity. With this information, could be a useful point on the treatment of these patients with immunomodulatory drugs.

Inferring source attribution from a multiyear multisource data set of Salmonella in Minnesota

Salmonella enterica is a global health concern because of its widespread association with foodborne illness. Bayesian models have been developed to attribute the burden of human salmonellosis to specific sources with the ultimate objective of prioritizing intervention strategies. Important considerations of source attribution models include the evaluation of the quality of input data, assessment of whether attribution results logically reflect the data trends and identification of patterns within the data that might explain the detailed contribution of different sources to the disease burden. Here, more than 12,000 non-typhoidal Salmonella isolates from human, bovine, porcine, chicken and turkey sources that originated in Minnesota were analysed. A modified Bayesian source attribution model (available in a dedicated R package), accounting for non-sampled sources of infection, attributed 4,672 human cases to sources assessed here. Most (60%) cases were attributed to chicken, although there was a spike in cases attributed to a non-sampled source in the second half of the study period. Molecular epidemiological analysis methods were used to supplement risk modelling, and a visual attribution application was developed to facilitate data exploration and comprehension of the large multiyear data set assessed here. A large amount of within-source diversity and low similarity between sources was observed, and visual exploration of data provided clues into variations driving the attribution modelling results. Results from this pillared approach provided first attribution estimates for Salmonella in Minnesota and offer an understanding of current data gaps as well as key pathogen population features, such as serotype frequency, similarity and diversity across the sources. Results here will be used to inform policy and management strategies ultimately intended to prevent and control Salmonella infection in the state.

Detection of a novel sapelovirus in central nervous tissue of pigs with polioencephalomyelitis in the USA

An approximately 3,000 finishing swine operation in the United States experienced an outbreak of an atypical neurologic disease in 11-weeks-old pigs with an overall morbidity of 20% and case fatality rate of 30%. The clinical onset and progression of signs in affected pigs varied but included inappetence, compromised ambulation, ataxia, incoordination, mental dullness, paresis, paralysis and decreased response to environmental stimuli. Tissues from affected pigs were submitted for diagnostic investigation. Histopathologic examination of the cerebrum, cerebellum and spinal cord revealed severe lymphoplasmacytic and necrotizing polioencephalomyelitis with multifocal areas of gliosis and neuron satellitosis, suggestive of a neurotropic viral infection. Bacterial pathogens were not isolated by culture of neurologic tissue from affected pigs. Samples tested by polymerase chain reaction (PCR) were negative for pseudorabies virus and atypical porcine pestivirus. Immunohistochemistry for porcine reproductive and respiratory syndrome virus, porcine circovirus and Listeria was negative. Porcine sapelovirus (PSV) was identified in spinal cord by a nested PCR used to detect porcine enterovirus, porcine teschovirus and PSV. Next-generation sequencing of brainstem and spinal cord samples identified PSV and the absence of other or novel pathogens. In addition, Sapelovirus A mRNA was detected in neurons and nerve roots of the spinal cord by in situ hybridization. The PSV is genetically novel with an overall 94% amino acid identity and 86% nucleotide identity to a recently reported sapelovirus from Korea. This is the first case report in the United States associating sapelovirus with severe polioencephalomyelitis in pigs.

Measurement of Cortical Thickness and Volume of Subcortical Structures in Multiple Sclerosis: Agreement between 2D Spin-Echo and 3D MPRAGE T1-Weighted Images

BACKGROUND AND PURPOSE

Gray matter pathology is known to occur in multiple sclerosis and is related to disease outcomes. FreeSurfer and the FMRIB Integrated Registration and Segmentation Tool (FIRST) have been developed for measuring cortical and subcortical gray matter in 3D-gradient-echo T1-weighted images. Unfortunately, most historical MS cohorts do not have 3D-gradient-echo, but 2D-spin-echo images instead. We aimed to evaluate whether cortical thickness and the volume of subcortical structures measured with FreeSurfer and FIRST could be reliably measured in 2D-spin-echo images and to investigate the strength and direction of clinicoradiologic correlations.

MATERIALS AND METHODS

Thirty-eight patients with MS and 2D-spin-echo and 3D-gradient-echo T1-weighted images obtained at the same time were analyzed by using FreeSurfer and FIRST. The intraclass correlation coefficient between the estimates was obtained. Correlation coefficients were used to investigate clinicoradiologic associations.

RESULTS

Subcortical volumes obtained with both FreeSurfer and FIRST showed good agreement between 2D-spin-echo and 3D-gradient-echo images, with 68.8%-76.2% of the structures having either a substantial or almost perfect agreement. Nevertheless, with FIRST with 2D-spin-echo, 18% of patients had mis-segmentation. Cortical thickness had the lowest intraclass correlation coefficient values, with only 1 structure (1.4%) having substantial agreement. Disease duration and the Expanded Disability Status Scale showed a moderate correlation with most of the subcortical structures measured with 3D-gradient-echo images, but some correlations lost significance with 2D-spin-echo images, especially with FIRST.

CONCLUSIONS

Cortical thickness estimates with FreeSurfer on 2D-spin-echo images are inaccurate. Subcortical volume estimates obtained with FreeSurfer and FIRST on 2D-spin-echo images seem to be reliable, with acceptable clinicoradiologic correlations for FreeSurfer.

Hippocampal and Deep Gray Matter Nuclei Atrophy Is Relevant for Explaining Cognitive Impairment in MS: A Multicenter Study

BACKGROUND AND PURPOSE

The structural MR imaging correlates of cognitive impairment in multiple sclerosis are still debated. This study assessed lesional and atrophy measures of white matter and gray matter involvement in patients with MS acquired in 7 European sites to identify the MR imaging variables most closely associated with cognitive dysfunction.

MATERIALS AND METHODS

Brain dual-echo, 3D T1-weighted, and double inversion recovery scans were acquired at 3T from 62 patients with relapsing-remitting MS and 65 controls. Patients with at least 2 neuropsychological tests with abnormal findings were considered cognitively impaired. Focal WM and cortical lesions were identified, and volumetric measures from WM, cortical GM, the hippocampus, and deep GM nuclei were obtained. Age- and site-adjusted models were used to compare lesion and volumetric MR imaging variables between patients with MS who were cognitively impaired and cognitively preserved. A multivariate analysis identified MR imaging variables associated with cognitive scores and disability.

RESULTS

Twenty-three patients (38%) were cognitively impaired. Compared with those with who were cognitively preserved, patients with MS with cognitive impairment had higher T2 and T1 lesion volumes and a trend toward a higher number of cortical lesions. Significant brain, cortical GM, hippocampal, deep GM nuclei, and WM atrophy was found in patients with MS with cognitive impairment versus those who were cognitively preserved. Hippocampal and deep GM nuclei atrophy were the best predictors of cognitive impairment, while WM atrophy was the best predictor of disability.

CONCLUSIONS

Hippocampal and deep GM nuclei atrophy are key factors associated with cognitive impairment in MS. These MR imaging measures could be applied in a multicenter context, with cognition as clinical outcome.

[Response to treatment with interferon beta in patients with multiple sclerosis. Validation of the Rio Score]

INTRODUCTION

Different criteria have been proposed for the response to treatment with interferon beta, and the Rio Score is one of the most widely used. The aim of this study was to validate the usefulness of the Rio Score in an independent cohort.

PATIENTS AND METHODS

A multi-centre, prospective, longitudinal study was conducted on patients with relapsing-remitting multiple sclerosis treated with interferon beta. The patients were classified according to the presence of attacks, active lesions (new in T2 or gadolinium enhancing lesions) in magnetic resonance imaging, a confirmed increase in disability or combinations of these variables (attacks, increase on the Expanded Disability Status Scale and active lesions) after one year's treatment. Regression analysis was used in order to identify the response-predicting variables after a three-year follow-up.

RESULTS

The sample consisted of 249 patients with relapsing-remitting multiple sclerosis. The logistic model confirmed that the presence of two (odds ratio = 6.6; CI 95% = 2.7-16.1; p < 0.0001) or three (odds ratio = 8.5; CI 95% = 1.6-46; p < 0.01) positive variables during the first year of treatment were indicative of a significant risk of activity (attacks or progression) in the next two years.

CONCLUSIONS

The usefulness of the Rio Score is confirmed, in an independent cohort, as a means of identifying patients with a higher risk of developing clinical activity or progression of disability during treatment with interferon beta.

Neurofilament light chain level is a weak risk factor for the development of MS

Objective:

To determine the prognostic value of selected biomarkers in clinically isolated syndromes (CIS) for conversion to multiple sclerosis (MS) and disability accrual.

Methods:

Data were acquired from 2 CIS cohorts. The screening phase evaluated patients developing clinically definite MS (CIS-CDMS) and patients who remained as CIS during a 2-year minimum follow-up (CIS-CIS). We determined levels of neurofascin, semaphorin 3A, fetuin A, glial fibrillary acidic protein, and neurofilament light (NfL) and heavy chains in CSF (estimated mean [95% confidence interval; CI]). We evaluated associations between biomarker levels, conversion, disability, and magnetic resonance parameters. In the replication phase, we determined NfL levels (n = 155) using a 900 ng/L cutoff. Primary endpoints in uni- and multivariate analyses were CDMS and 2010 McDonald MS.

Results:

The only biomarker showing significant differences in the screening was NfL (CIS-CDMS 1,553.1 [1,208.7–1,897.5] ng/L and CIS-CIS 499.0 [168.8–829.2] ng/L, p < 0.0001). The strongest associations were with brain parenchymal fraction change (r_s = −0.892) and percentage brain volume change (r_s = −0.842) at 5 years. NfL did not correlate with disability. In the replication phase, more NfL-positive patients, according to the cutoff, evolved to MS. Every 100-ng/L increase in NfL predicted CDMS (hazard ratio [HR] = 1.009, 95% CI 1.005–1.014) and McDonald MS (HR = 1.009, 95% CI 1.005–1.013), remaining significant for CDMS in the multivariate analysis (adjusted HR = 1.005, 95% CI 1.000–1.011). This risk was lower than the presence of oligoclonal bands or T2 lesions.

Conclusions:

NfL is a weak independent risk factor for MS. Its role as an axonal damage biomarker may be more relevant as suggested by its association with medium-term brain volume changes.

Grey matter atrophy is associated with disability increase in natalizumab-treated patients

Background:

Brain volume loss (BVL) is a key outcome in multiple sclerosis (MS) trials. Natalizumab is highly effective on inflammation with moderate impact on atrophy.

Objective:

To explore BVL in patients receiving natalizumab with an emphasis on grey matter (GM).

Methods:

We performed a retrospective post hoc analysis of BVL in 38 patients receiving natalizumab for 3 years using longitudinal voxel-based morphometry (VBM) and FreeSurfer.

Results:

Significant BVL was observed during first year: brain parenchymal fraction (BPF): −1.12% ( p < 0.001); white matter fraction (WMF): −0.9% ( p = 0.001); grey matter fraction (GMF): −1.28% ( p = 0.002). GM loss was found using VBM in bilateral cerebellum, cingulum, left > right fronto-parietal cortex, right > left hippocampus and left caudate. FreeSurfer showed significant volume losses in subcortical GM, brainstem and cerebellum, and cortical thinning in the left insula. In the second year, only WMF decrease (−0.6%; p = 0.015) was observed with no VBM changes, although FreeSurfer detected significant volume loss in thalamus, hippocampus and cerebellum. Baseline gadolinium enhancement influenced WMF and BPF changes during the first year, but not GMF. Patients with confirmed Expanded Disability Status Scale (EDSS) worsening at 3 years had lower baseline GMF and left thalamus volume and greater BVL over follow-up.

Conclusion:

BVL develops mainly during the first year of natalizumab therapy. GM changes are independent of baseline inflammation and correlate with disability.

Power estimation for non-standardized multisite studies

A concern for researchers planning multisite studies is that scanner and T1-weighted sequence-related biases on regional volumes could overshadow true effects, especially for studies with a heterogeneous set of scanners and sequences. Current approaches attempt to harmonize data by standardizing hardware, pulse sequences, and protocols, or by calibrating across sites using phantom-based corrections to ensure the same raw image intensities. We propose to avoid harmonization and phantom-based correction entirely. We hypothesized that the bias of estimated regional volumes is scaled between sites due to the contrast and gradient distortion differences between scanners and sequences. Given this assumption, we provide a new statistical framework and derive a power equation to define inclusion criteria for a set of sites based on the variability of their scaling factors. We estimated the scaling factors of 20 scanners with heterogeneous hardware and sequence parameters by scanning a single set of 12 subjects at sites across the United States and Europe. Regional volumes and their scaling factors were estimated for each site using Freesurfer's segmentation algorithm and ordinary least squares, respectively. The scaling factors were validated by comparing the theoretical and simulated power curves, performing a leave-one-out calibration of regional volumes, and evaluating the absolute agreement of all regional volumes between sites before and after calibration. Using our derived power equation, we were able to define the conditions under which harmonization is not necessary to achieve 80% power. This approach can inform choice of processing pipelines and outcome metrics for multisite studies based on scaling factor variability across sites, enabling collaboration between clinical and research institutions.

Assessing response to interferon-β in a multicenter dataset of patients with MS

OBJECTIVE

To provide new insights into the role of markers of response to interferon-β therapy in multiple sclerosis (MS) in a multicenter setting, focusing on the relevance of MRI lesions in combination with clinical variables.

METHODS

A large multicenter clinical dataset was collected within the Magnetic Resonance Imaging in MS (MAGNIMS) network. This included a large cohort of patients with relapsing-remitting MS on interferon-β treatment, MRI and clinical assessments during the first year of treatment, and clinical follow-up of at least 2 additional years. Heterogeneity among centers was assessed before pooling the data. The association of 1-year MRI or clinical relapses with the risk of treatment failure (defined as Expanded Disability Status Scale [EDSS] worsening or treatment switch for inefficacy) and of EDSS worsening alone was evaluated using multivariate Cox models.

RESULTS

A pooled dataset of 1,280 patients with relapsing-remitting MS from 9 MAGNIMS centers was analyzed. The risk of failure had a relevant increase with 1 relapse (hazard ratio [HR] 1.84, 95% confidence interval [CI] 1.39-2.44, p < 0.001) and ≥3 new T2 lesions (HR 1.55, 95% CI 0.92-2.60, p = 0.09). In patients without relapses and less than 3 new T2 lesions, the 3-year risk of failure and EDSS worsening were 17% and 15%; in patients with 1 relapse or ≥3 new T2 lesions, the risks were 27% and 22%; in patients with both conditions or more than 1 relapse, the risks were 48% (p < 0.001) and 29% (p < 0.001).

CONCLUSIONS

Substantial MRI activity, particularly if in combination with clinical relapses, during the first year of treatment with interferon-β indicates significant risk of treatment failure and EDSS worsening in the short term.