Late/delayed gadolinium enhancement in MRI after intravenous administration of extracellular gadolinium-based contrast agents: is it worth waiting?

The acquisition of images minutes or even hours after intravenous extracellular gadolinium-based contrast agents (GBCA) administration ("Late/Delayed Gadolinium Enhancement" imaging; in this review, further termed LGE) has gained significant prominence in recent years in magnetic resonance imaging. The major limitation of LGE is the long examination time; thus, it becomes necessary to understand when it is worth waiting time after the intravenous injection of GBCA and which additional information comes from LGE. LGE can potentially be applied to various anatomical sites, such as heart, arterial vessels, lung, brain, abdomen, breast, and the musculoskeletal system, with different pathophysiological mechanisms. One of the most popular clinical applications of LGE regards the assessment of myocardial tissue thanks to its ability to highlight areas of acute myocardial damage and fibrotic tissues. Other frequently applied clinical contexts involve the study of the urinary tract with magnetic resonance urography and identifying pathological abdominal processes characterized by high fibrous stroma, such as biliary tract tumors, autoimmune pancreatitis, or intestinal fibrosis in Crohn's disease. One of the current areas of heightened research interest revolves around the possibility of non-invasively studying the dynamics of neurofluids in the brain (the glymphatic system), the disruption of which could underlie many neurological disorders.

Go Green in Neuroradiology: towards reducing the environmental impact of its practice

Raising public awareness about the relevance of supporting sustainable practices is required owing to the phenomena of global warming caused by the rising production of greenhouse gases. The healthcare sector generates a relevant proportion of the total carbon emissions in developed countries, and radiology is estimated to be a major contributor to this carbon footprint. Neuroradiology markedly contributes to this negative environmental effect, as this radiological subspecialty generates a high proportion of diagnostic and interventional imaging procedures, the majority of them requiring high energy-intensive equipment. Therefore, neuroradiologists and neuroradiological departments are especially responsible for implementing decisions and initiatives able to reduce the unfavourable environmental effects of their activities, by focusing on four strategic pillars-reducing energy, water, and helium use; properly recycling and/or disposing of waste and residues (including contrast media); encouraging environmentally friendly behaviour; and reducing the effects of ionizing radiation on the environment. The purpose of this article is to alert neuroradiologists about their environmental responsibilities and to analyse the most productive strategic axes, goals, and lines of action that contribute to reducing the environmental impact associated with their professional activities.

Defining a standard set of health outcomes for patients with relapsing-remitting multiple sclerosis

BACKGROUND

Standardizing health outcomes is challenging in clinical management, but it also holds the potential for creating a healthcare system that is both more effective and efficient. The aim of the present study is to define a standardized set of health outcomes for managing Relapsing-Remitting Multiple Sclerosis (RRMS).

METHODS

The project was led and coordinated by a multidisciplinary scientific committee (SC), which included a literature review, a patient-focused group, three nominal group meetings, and two SC meetings.

RESULTS

36 outcome variables were included in the standard set: 24 clinical (including weight, smoking habit, comorbidities, disability, mobility, diagnosis of secondary progressive multiple sclerosis, relapsed-related variables, radiological variables, cognitive status and disease-related symptoms), nine treatment-related (pharmacological and non-pharmacological information), and 3 related to the impact of RRMS on the patient's life (quality of life, pregnancy desire, work-related difficulties). In addition, experts also agreed to collect 10 case-mix variables that may affect but cannot be controlled as part of the management of the condition: 4 sociodemographic (age, sex, race, and employment status) and 6 clinical (height, date of diagnosis and first episode, serological status, early symptoms, and number of relapses pre-diagnosis).

CONCLUSION

The information provided through the present standard set of outcome variables can improve the management of RRMS and promote patient-centred quality care.

Use of gadolinium-based contrast agents in multiple sclerosis: a review by the ESMRMB-GREC and ESNR Multiple Sclerosis Working Group

Magnetic resonance imaging (MRI) is the most sensitive technique for detecting inflammatory demyelinating lesions in multiple sclerosis (MS) and plays a crucial role in diagnosis and monitoring treatment effectiveness, and for predicting the disease course. In clinical practice, detection of MS lesions is mainly based on T2-weighted and contrast-enhanced T1-weighted sequences. Contrast-enhancing lesions (CEL) on T1-weighted sequences are related to (sub)acute inflammation, while new or enlarging T2 lesions reflect the permanent footprint from a previous acute inflammatory demyelinating event. These two types of MRI features provide redundant information, at least in regular monitoring of the disease. Due to the concern of gadolinium deposition after repetitive injections of gadolinium-based contrast agents (GBCAs), scientific organizations and regulatory agencies in Europe and North America have proposed that these contrast agents should be administered only if clinically necessary. In this article, we provide data on the mode of action of GBCAs in MS, the indications of the use of these agents in clinical practice, their value in MS for diagnostic, prognostic, and monitoring purposes, and their use in specific populations (children, pregnant women, and breast-feeders). We discuss imaging strategies that achieve the highest sensitivity for detecting CELs in compliance with the safety regulations established by different regulatory agencies. Finally, we will briefly discuss some alternatives to the use of GBCA for detecting blood-brain barrier disruption in MS lesions. CLINICAL RELEVANCE STATEMENT: Although use of GBCA at diagnostic workup of suspected MS is highly valuable for diagnostic and prognostic purposes, their use in routine monitoring is not mandatory and must be reduced, as detection of disease activity can be based on the identification of new or enlarging lesions on T2-weighted images. KEY POINTS: • Both the EMA and the FDA state that the use of GBCA in medicine should be restricted to clinical scenarios in which the additional information offered by the contrast agent is required. • The use of GBCA is generally recommended in the diagnostic workup in subjects with suspected MS and is generally not necessary for routine monitoring in clinical practice. • Alternative MRI-based approaches for detecting acute focal inflammatory MS lesions are not yet ready to be used in clinical practice.

Optic chiasm manual and automated measurements in sub-acute optic neuritis with OCT and MRI correlations

PURPOSE

The optic chiasm (OC) is a central structure in the visual pathway and can be visualized in conventional MRI, but no consensus regarding its measurement has been defined. We aim to investigate the most reproducible manual approach to OC measurement and to explore associations of OC with optical coherence tomography (OCT) parameters, and automatic brain segmentation (FreeSurfer) in subacute optic neuritis (sON), multiple sclerosis without optic neuritis (MSwoON), and healthy subjects (HS).

MATERIALS AND METHODS

We reproduced two previously reported methodologies and implemented a new proposed simplified approach, entitled optic chiasm mean area (OCMA). The intra and inter-rater reliability and reproducibility were assessed through the intraclass correlation (ICC) and Dice similarity (DSC) coefficients. Partial correlations were calculated to gauge the associations between OCMA fraction (OCMA divided by total intracranial volume), brain regional segmentations derived from FreeSurfer, and OCT parameters.

RESULTS

We have analysed 43 sON, 20 MSwoON, and 20 HS. OCMA presented better results for reliability in both intra- and inter-rater analysis (excellent ICC and DSC with over 80% overlap between masks), as compared to the other two approaches. OCMA fraction was associated with OC volume fraction obtained with Freesurfer in all groups, brain parenchymal fraction, and OCT parameters in MSwoON.

CONCLUSIONS

The OCMA is a simplified approach to measure OC atrophy, has a higher reliability than the current approaches and shows association with an automated method. OC-derived measures seem to reflect diffuse neurodegenerative damage, whereas, in patients with subacute ON, it may be associated with local damage.

T1/T2-weighted ratio: A feasible MRI biomarker in multiple sclerosis

T1/T2-weighted ratio is a novel magnetic resonance imaging (MRI) biomarker based on conventional sequences, related to microstructural integrity and with increasing use in multiple sclerosis (MS) research. Different from other advanced MRI techniques, this method has the advantage of being based on routinely acquired MRI sequences, a feature that enables analysis of retrospective cohorts with considerable clinical value. This article provides an overview of this method, describing the previous cross-sectional and longitudinal findings in the main MS clinical phenotypes and in different brain tissues: focal white matter (WM) lesions, normal-appearing white matter (NAWM), cortical gray matter (GM), and deep normal-appearing gray matter (NAGM). We also discuss the clinical associations, possible reasons for conflicting results, correlations with other MRI-based measures, and histopathological associations. We highlight the limitations of the biomarker itself and the methodology of each study. Finally, we update the reader on its potential use as an imaging biomarker in research.

Energy consumption in MRI: Determinants and management options

BACKGROUND

Energy consumption awareness is a known concern, and radiology departments have energy-intensive consuming machines. The means of energy consumption management in MRI scanners have yet to be evaluated.

PURPOSE

To measure the MRI energy consumption and to evaluate the means to reduce it.

MATERIALS AND METHODS

Data was retrieved for two MRI scanners through the hospital's automated energy consumption measurement software. After correlation with picture archiving and communication system (PACS) files, they were segmented by machine and mode (as follows: stand-by, idle and active) and analyzed. Active mode data for a specific brain MRI protocol have been isolated, and equivalent low energy consuming protocol was made. Both were performed on phantom and compared. Same protocol was performed on a phantom using 3.0T 16 and 32 head channels coils. Multiples sequences were acquired on phantom to evaluate power consumption.

RESULTS

Stand-by mode accounted for 60 % of machine time and 40 % of energy consumption, active mode accounted for 20 % machine time and 40 % energy consumption, idle mode for 20 % imachine time and 20 % consumption. DWI and TOF sequences were the most consuming in our brain-MRI protocol. The low energy consuming protocol allowed a saving of approximately 10 % of energy consumption, which amounted for 0.20€ for each examination. This difference was mainly due to an energy consumption reduction of the DWI sequence. There were no difference in consumption between a 3.0T 16 and 32 channels head coils. Sequence's active power and duration (especially considering slice thickness) have to be taken into account when trying to optimize energy consumption.

CONCLUSION

There are two key factors to consider when trying to reduce MRI scan energy consumption. Stand-by mode energy consumption has to be taken into account when choosing an MRI scan, as it can't be changed further on. Active mode energy consumption is dependent of the MRI protocols used, and can be reduced with sequences adaptation, which must take into account sequence's active power and duration, on top of image quality.

Imaging of Drug-Related Vasculopathy

Illicit and recreational drugs, such as cocaine, heroin, amphetamines, and marijuana, can result in drug-related vasculitis or vasculopathy. Similarly, the use of certain antithyroid, oncologic, and immunosuppressive medications for therapeutic purposes can lead to vasculopathy. This in turn may result in significant complications in the central nervous system, including intracranial hemorrhage and stroke. Cocaine abuse can also lead to midline destructive lesions of the sinonasal complex. MR imaging, Vessel Wall imaging, and CT/CTA are valuable imaging tools for the evaluation of patients with suspected drug-induced vasculopathy or vasculitis. This article reviews the pathomechanism, clinical presentation, and imaging findings of vasculopathy related to drug abuse and prescribed medications.

Optic nerve topography in multiple sclerosis diagnostic criteria: Existing knowledge and future directions

Current diagnostic criteria for multiple sclerosis (MS) do not consider the optic nerve as a typical topography for establishing the diagnosis. Recent studies have proved the utility of optic nerve magnetic resonance imaging, optical coherence tomography and visual evoked potentials in detecting optic nerve lesions during the early stages of MS. In addition, emerging evidence supports the inclusion of optic nerve topography as a fifth region to fulfil the dissemination in space criteria. Anticipating a modification in the McDonald criteria, it is crucial for neurologists to familiarize with the diagnostic properties of each test in detecting optic nerve lesions and understand how to incorporate them into the MS diagnostic process. Therefore, the objective of this article is to review the existing evidence supporting the use of these tests in the diagnostic process of MS and provide a practical algorithm that can serve as a valuable guide for clinical practice.

Diagnostic Performance of Cortical Lesions and the Central Vein Sign in Multiple Sclerosis

Importance

Multiple sclerosis (MS) misdiagnosis remains an important issue in clinical practice.

Objective

To quantify the performance of cortical lesions (CLs) and central vein sign (CVS) in distinguishing MS from other conditions showing brain lesions on magnetic resonance imaging (MRI).

Design, Setting, and Participants

This was a retrospective, cross-sectional multicenter study, with clinical and MRI data acquired between January 2010 and May 2020. Centralized MRI analysis was conducted between July 2020 and December 2022 by 2 raters blinded to participants' diagnosis. Participants were recruited from 14 European centers and from a multicenter pan-European cohort. Eligible participants had a diagnosis of MS, clinically isolated syndrome (CIS), or non-MS conditions; availability of a brain 3-T MRI scan with at least 1 sequence suitable for CL and CVS assessment; presence of T2-hyperintense white matter lesions (WMLs). A total of 1051 individuals were included with either MS/CIS (n = 599; 386 [64.4%] female; mean [SD] age, 41.5 [12.3] years) or non-MS conditions (including other neuroinflammatory disorders, cerebrovascular disease, migraine, and incidental WMLs in healthy control individuals; n = 452; 302 [66.8%] female; mean [SD] age, 49.2 [14.5] years). Five individuals were excluded due to missing clinical or demographic information (n = 3) or unclear diagnosis (n = 2).

Exposures

MS/CIS vs non-MS conditions.

Main Outcomes and Measures

Area under the receiver operating characteristic curves (AUCs) were used to explore the diagnostic performance of CLs and the CVS in isolation and in combination; sensitivity, specificity, and accuracy were calculated for various cutoffs. The diagnostic importance of CLs and CVS compared to conventional MRI features (ie, presence of infratentorial, periventricular, and juxtacortical WMLs) was ranked with a random forest model.

Results

The presence of CLs and the previously proposed 40% CVS rule had a sensitivity, specificity, and accuracy for MS of 59.0% (95% CI, 55.1-62.8), 93.6% (95% CI, 91.4-95.6), and 73.9% (95% CI, 71.6-76.3) and 78.7% (95% CI, 75.5-82.0), 86.0% (95% CI, 82.1-89.5), and 81.5% (95% CI, 78.9-83.7), respectively. The diagnostic performance of the CVS (AUC, 0.89 [95% CI, 0.86-0.91]) was superior to that of CLs (AUC, 0.77 [95% CI, 0.75-0.80]; P < .001), and was increased when combining the 2 imaging markers (AUC, 0.92 [95% CI, 0.90-0.94]; P = .04); in the random forest model, both CVS and CLs outperformed the presence of infratentorial, periventricular, and juxtacortical WMLs in supporting MS differential diagnosis.

Conclusions and Relevance

The findings in this study suggest that CVS and CLs may be valuable tools to increase the accuracy of MS diagnosis.

The role of gadolinium-based contrast agents in magnetic resonance imaging structured reporting and data systems (RADS)

Among the 28 reporting and data systems (RADS) available in the literature, we identified 15 RADS that can be used in Magnetic Resonance Imaging (MRI). Performing examinations without using gadolinium-based contrast agents (GBCA) has benefits, but GBCA administration is often required to achieve an early and accurate diagnosis. The aim of the present review is to summarize the current role of GBCA in MRI RADS. This overview suggests that GBCA are today required in most of the current RADS and are expected to be used in most MRIs performed in patients with cancer. Dynamic contrast enhancement is required for correct scores calculation in PI-RADS and VI-RADS, although scientific evidence may lead in the future to avoid the GBCA administration in these two RADS. In Bone-RADS, contrast enhancement can be required to classify an aggressive lesion. In RADS scoring on whole body-MRI datasets (MET-RADS-P, MY-RADS and ONCO-RADS), in NS-RADS and in Node-RADS, GBCA administration is optional thanks to the intrinsic high contrast resolution of MRI. Future studies are needed to evaluate the impact of the high T1 relaxivity GBCA on the assignment of RADS scores.

Global and Regional Deep Learning Models for Multiple Sclerosis Stratification From MRI

BACKGROUND

The combination of anatomical MRI and deep learning-based methods such as convolutional neural networks (CNNs) is a promising strategy to build predictive models of multiple sclerosis (MS) prognosis. However, studies assessing the effect of different input strategies on model's performance are lacking.

PURPOSE

To compare whole-brain input sampling strategies and regional/specific-tissue strategies, which focus on a priori known relevant areas for disability accrual, to stratify MS patients based on their disability level.

STUDY TYPE

Retrospective.

SUBJECTS

Three hundred nineteen MS patients (382 brain MRI scans) with clinical assessment of disability level performed within the following 6 months (~70% training/~15% validation/~15% inference in-house dataset) and 440 MS patients from multiple centers (independent external validation cohort).

FIELD STRENGTH/SEQUENCE

Single vendor 1.5 T or 3.0 T. Magnetization-Prepared Rapid Gradient-Echo and Fluid-Attenuated Inversion Recovery sequences.

ASSESSMENT

A 7-fold patient cross validation strategy was used to train a 3D-CNN to classify patients into two groups, Expanded Disability Status Scale score (EDSS) ≥ 3.0 or EDSS < 3.0. Two strategies were investigated: 1) a global approach, taking the whole brain volume as input and 2) regional approaches using five different regions-of-interest: white matter, gray matter, subcortical gray matter, ventricles, and brainstem structures. The performance of the models was assessed in the in-house and the independent external cohorts.

STATISTICAL TESTS

Balanced accuracy, sensitivity, specificity, area under receiver operating characteristic (ROC) curve (AUC).

RESULTS

With the in-house dataset, the gray matter regional model showed the highest stratification accuracy (81%), followed by the global approach (79%). In the external dataset, without any further retraining, an accuracy of 72% was achieved for the white matter model and 71% for the global approach.

DATA CONCLUSION

The global approach offered the best trade-off between internal performance and external validation to stratify MS patients based on accumulated disability.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

Multiple sclerosis imaging in clinical practice: a European-wide survey of 428 centers and conclusions by the ESNR Working Group

OBJECTIVES

To evaluate compliance with the available recommendations, we assessed the current clinical practice of imaging in the evaluation of multiple sclerosis (MS).

METHODS

An online questionnaire was emailed to all members and affiliates. Information was gathered on applied MR imaging protocols, gadolinium-based contrast agents (GBCA) use and image analysis. We compared the survey results with the Magnetic Resonance Imaging in MS (MAGNIMS) recommendations considered as the reference standard.

RESULTS

A total of 428 entries were received from 44 countries. Of these, 82% of responders were neuroradiologists. 55% performed more than ten scans per week for MS imaging. The systematic use of 3 T is rare (18%). Over 90% follow specific protocol recommendations with 3D FLAIR, T2-weighted and DWI being the most frequently used sequences. Over 50% use SWI at initial diagnosis and 3D gradient-echo T1-weighted imaging is the most used MRI sequence for pre- and post-contrast imaging. Mismatches with recommendations were identified including the use of only one sagittal T2-weighted sequence for spinal cord imaging, the systematic use of GBCA at follow-up (over 30% of institutions), a delay time shorter than 5 min after GBCA administration (25%) and an inadequate follow-up duration in pediatric acute disseminated encephalomyelitis (80%). There is scarce use of automated software to compare images or to assess atrophy (13% and 7%). The proportions do not differ significantly between academic and non-academic institutions.

CONCLUSIONS

While current practice in MS imaging is rather homogeneous across Europe, our survey suggests that recommendations are only partially followed.

CLINICAL RELEVANCE STATEMENT

Hurdles were identified, mainly in the areas of GBCA use, spinal cord imaging, underuse of specific MRI sequences and monitoring strategies. This work will help radiologists to identify the mismatches between their own practices and the recommendations and act upon them.

KEY POINTS

• While current practice in MS imaging is rather homogeneous across Europe, our survey suggests that available recommendations are only partially followed. • Several hurdles have been identified through the survey that mainly lies in the areas of GBCA use, spinal cord imaging, underuse of specific MRI sequences and monitoring strategies.

Recommendations for the coordination of Neurology and Neuroradiology Departments in the management of patients with multiple sclerosis

INTRODUCTION

Magnetic resonance imaging (MRI) is widely used for the diagnosis and follow-up of patients with multiple sclerosis (MS). Coordination between neurology and neuroradiology departments is crucial for performing and interpreting radiological studies as efficiently and as accurately as possible. However, improvements can be made in the communication between these departments in many Spanish hospitals.

METHODS

A panel of 17 neurologists and neuroradiologists from 8 Spanish hospitals held in-person and online meetings to draft a series of good practice guidelines for the coordinated management of MS. The drafting process included 4 phases: 1) establishing the scope of the guidelines and the methodology of the study; 2) literature review on good practices or recommendations on the use of MRI in MS; 3) discussion and consensus between experts; and 4) validation of the contents.

RESULTS

The expert panel agreed a total of 9 recommendations for improving coordination between neurology and neuroradiology departments. The recommendations revolve around 4 main pillars: 1) standardising the process for requesting and scheduling MRI studies and reports; 2) designing common protocols for MRI studies; 3) establishing multidisciplinary committees and coordination meetings; and 4) creating formal communication channels between both departments.

CONCLUSIONS

These consensus recommendations are intended to optimise coordination between neurologists and neuroradiologists, with the ultimate goal of improving the diagnosis and follow-up of patients with MS.

Estimation of the density of veins from susceptibility-weighted imaging by using Mamdani fuzzy-type rule-based system. Investigating the neurovascular coupling in migraine

BACKGROUND AND PURPOSE

An impaired neurovascular coupling has been described as a possible player in neurodegeneration and cognitive decline. Migraine is a recurrent and incapacitating disorder that starts early in life and has shown neurovascular coupling abnormalities. Despite its high prevalence, the physiology and underlying mechanisms are poorly understood. In this context, new biomarkers from magnetic resonance imaging (MRI) are needed to bring new knowledge into the field. The aim of this study was to determine the vein density from Susceptibility-Weighted Imaging (SWI) MRI, in subjects with migraine and healthy controls; and to assess whether it relates to Resting-State functional MRI (RS-fMRI).

MATERIALS AND METHODS

The cohort included 30 healthy controls and 70 subjects with migraine (26 episodic, 44 chronic) who underwent a brain 3.0 T MRI. Clinical characteristics were also collected. Maps of density of veins were generated based on a Mamdani Fuzzy-Type Rule-Based System from the SWI MRI. Mean values of vein density were obtained in grey (GM) and white matter (WM) Freesurfer lobar parcellations. The Amplitude of Low-Frequency Fluctuations (ALFF) image was calculated for the RS-fMRI, and the mean values over the parcellated GM lobes were estimated. Differences between groups were assessed through and analysis of variance (age, sex, education and anxiety as covariates; p < 0.05), followed by post-hoc comparisons. Associations were run between clinical and MRI-derived variables.

RESULTS

When comparing the density of veins in GM, no differences between groups were found, neither associations with clinical variables. The density of veins was significantly higher in the WM of the occipital lobe for subjects with chronic migraine compared to controls (30%, p < 0.05). WM vein density in either frontal, temporal or cingulate regions was associated with clinical variables such as headache days, disability scores, and cognitive impairment (r between 0.25 and 0.41; p < 0.05). Mean values of ALFF did not differ significantly between controls and subjects with migraine. Strong significant associations between vein density and ALFF measures were obtained in most GM lobes for healthy subjects (r between 0.50 and 0.67; p < 0.05), instead, vein density in WM was significantly associated with ALFF for subjects with migraine (r between 0.32 and 0.58; p < 0.05).

CONCLUSIONS

Results point towards an increase in vein density in subjects with migraine, when compared to healthy controls. In addition, the association between GM vein density and ALFF found in healthy subjects was lost in migraine. Taken together, these results support the idea of abnormalities in the neurovascular coupling in migraine. Quantitative SWI MRI indicators in migraine might be an interesting target that may contribute to its comprehension.

Skin Toxicity After Exposure to Gadolinium-Based Contrast Agents in Normal Renal Function, Using Clinical Approved Doses: Current Status of Preclinical and Clinical Studies

OBJECTIVES

The aim of this study was to summarize the current preclinical and clinical evidence on the association between exposure to gadolinium (Gd) compounds and skin toxicity in a setting similar to clinical practice.

MATERIALS AND METHODS

A search of MEDLINE and PubMed references from January 2000 to December 2022 was performed using keywords related to gadolinium deposition and its effects on the skin, such as "gadolinium," "gadolinium-based contrast agents," "skin," "deposition," and "toxicity." In addition, cross-referencing was added when appropriate. For preclinical in vitro studies, we included all the studies that analyzed the response of human dermal fibroblasts to exposure to various gadolinium compounds. For preclinical animal studies and clinical studies, we included only those that analyzed animals or patients with preserved renal function (estimated glomerular filtration rate >30 mL/min/1.73 m 2 ), using a dosage of gadolinium-based contrast agents (GBCAs) similar to that commonly applied (0.1 mmol/kg).

RESULTS

Forty studies were selected. Preclinical findings suggest that Gd compounds can produce profibrotic responses in the skin in vitro, through the activation and proliferation of dermal fibroblasts and promoting their myofibroblast differentiation. Gadolinium influences the process of collagen production and the collagen content of skin, by increasing the levels of matrix metalloproteinase-1 and tissue inhibitor of metalloproteinase-1. Preclinical animal studies show that Gd can deposit in the skin with higher concentrations when linear GBCAs are applied. However, these deposits decrease over time and are not associated with obvious macroscopic or histological modifications. The clinical relevance of GBCAs in inducing small fiber neuropathy remains to be determined. Clinical studies show that Gd is detectable in the skin and hair of subjects with normal renal function in higher concentrations after intravenous administration of linear compared with macrocyclic GBCA. However, these deposits decrease over time and are not associated with cutaneous or histological modifications. Also, subclinical dermal involvement related to linear GBCA exposure may be detectable on brain MRI. There is no conclusive evidence to support a causal relationship between GBCA administration at the clinical dose and cutaneous manifestations in patients with normal renal function.

CONCLUSIONS

Gadolinium can produce profibrotic responses in the skin, especially acting on fibroblasts, as shown by preclinical in vitro studies. Gadolinium deposits are detectable in the skin even in subjects with normal renal function with higher concentrations when linear GBCAs are used, as confirmed by both preclinical animal and human studies. There is no proof to date of a cause-effect relationship between GBCA administration at clinical doses and cutaneous consequences in patients with normal renal function. Multiple factors, yet to be determined, should be considered for sporadic patients with normal renal function who develop clinical skin manifestations temporally related to GBCA administration.

Validation of a New Semiautomated Segmentation Pipeline Based on the Spinal Cord Toolbox DeepSeg Algorithm to Estimate the Cervical Canal Area

BACKGROUND AND PURPOSE

As in the brain reserve concept, a larger cervical canal area may also protect against disability. In this context, a semiautomated pipeline has been developed to obtain quantitative estimations of the cervical canal area. The aim of the study was to validate the pipeline, to evaluate the consistency of the cervical canal area measurements during a 1-year period, and to compare cervical canal area estimations obtained from brain and cervical MRI acquisitions.

MATERIALS AND METHODS

Eight healthy controls and 18 patients with MS underwent baseline and follow-up 3T brain and cervical spine sagittal 3D MPRAGE. The cervical canal area was measured in all acquisitions, and estimations obtained with the proposed pipeline were compared with manual segmentations performed by 1 evaluator using the Dice similarity coefficient. The cervical canal area estimations obtained on baseline and follow-up T1WI were compared; brain and cervical cord acquisitions were also compared using the individual and average intraclass correlation coefficients.

RESULTS

The agreement between the manual cervical canal area masks and the masks provided by the proposed pipeline was excellent, with a mean Dice similarity coefficient mean of 0.90 (range, 0.73-0.97). The cervical canal area estimations obtained from baseline and follow-up scans showed a good level of concordance (intraclass correlation coefficient = 0.76; 95% CI, 0.44-0.88); estimations obtained from brain and cervical MRIs also had good agreement (intraclass correlation coefficient = 0.77; 95% CI, 0.45-0.90).

CONCLUSIONS

The proposed pipeline is a reliable tool to estimate the cervical canal area. The cervical canal area is a stable measure across time; moreover, when cervical sequences are not available, the cervical canal area could be estimated using brain T1WI.

Assessing the Equivalence of Brain-Derived Measures from Two 3D T1-Weighted Acquisitions: One Covering the Brain and One Covering the Brain and Spinal Cord

BACKGROUND AND PURPOSE

In MS, it is common to acquire brain and spinal cord MR imaging sequences separately to assess the extent of the disease. The goal of this study was to see how replacing the traditional brain T1-weighted images (brain-T1) with an acquisition that included both the brain and the cervical spinal cord (cns-T1) affected brain- and spinal cord-derived measures.

MATERIALS AND METHODS

Thirty-six healthy controls (HC) and 42 patients with MS were included. Of those, 18 HC and 35 patients with MS had baseline and follow-up at 1 year acquired on a 3T magnet. Two 3D T1-weighted images (brain-T1 and cns-T1) were acquired at each time point. Regional cortical thickness and volumes were determined with FastSurfer, and the percentage brain volume change per year was obtained with SIENA. The spinal cord area was estimated with the Spinal Cord Toolbox. Intraclass correlation coefficients (ICC) were calculated to check for consistency of measures obtained from brain-T1 and cns-T1.

RESULTS

Cortical thickness measures showed an ICC >0.75 in 94% of regions in healthy controls and 80% in patients with MS. Estimated regional volumes had an ICC >0.88, and the percentage brain volume change had an ICC >0.79 for both groups. The spinal cord area measures had an ICC of 0.68 in healthy controls and 0.92 in patients with MS.

CONCLUSIONS

Brain measurements obtained from 3D cns-T1 are highly equivalent to those obtained from a brain-T1, suggesting that it could be feasible to replace the brain-T1 with cns-T1.

[Rapidly progressive intracranial large artery aterosclerosis, a rare stroke etiology]

INTRODUCTION

Intracranial atheromatosis is one of the most frequent causes of stroke. It is usually a slowly progressive process and normally associated with the sum of vascular risk factors.

CASE REPORT

In this case we present a rapidly progressive development of intracranial atheromatosis demonstrated by serial neuroimaging techniques and sample analysis in a 72-year-old female patient with high levels of interleukin-6 and C-reactive protein, with no signs of vasculitis.

CONCLUSION

Rapidly progressive intracranial atheromatosis should be considered in adult patients over 50 years of age with recurrent stroke.

Deciphering multiple sclerosis disability with deep learning attention maps on clinical MRI

The application of convolutional neural networks (CNNs) to MRI data has emerged as a promising approach to achieving unprecedented levels of accuracy when predicting the course of neurological conditions, including multiple sclerosis, by means of extracting image features not detectable through conventional methods. Additionally, the study of CNN-derived attention maps, which indicate the most relevant anatomical features for CNN-based decisions, has the potential to uncover key disease mechanisms leading to disability accumulation. From a cohort of patients prospectively followed up after a first demyelinating attack, we selected those with T1-weighted and T2-FLAIR brain MRI sequences available for image analysis and a clinical assessment performed within the following six months (N = 319). Patients were divided into two groups according to expanded disability status scale (EDSS) score: ≥3.0 and < 3.0. A 3D-CNN model predicted the class using whole-brain MRI scans as input. A comparison with a logistic regression (LR) model using volumetric measurements as explanatory variables and a validation of the CNN model on an independent dataset with similar characteristics (N = 440) were also performed. The layer-wise relevance propagation method was used to obtain individual attention maps. The CNN model achieved a mean accuracy of 79% and proved to be superior to the equivalent LR-model (77%). Additionally, the model was successfully validated in the independent external cohort without any re-training (accuracy = 71%). Attention-map analyses revealed the predominant role of frontotemporal cortex and cerebellum for CNN decisions, suggesting that the mechanisms leading to disability accrual exceed the mere presence of brain lesions or atrophy and probably involve how damage is distributed in the central nervous system.

Using The Virtual Brain to study the relationship between structural and functional connectivity in patients with multiple sclerosis: a multicenter study

The relationship between structural connectivity (SC) and functional connectivity (FC) captured from magnetic resonance imaging, as well as its interaction with disability and cognitive impairment, is not well understood in people with multiple sclerosis (pwMS). The Virtual Brain (TVB) is an open-source brain simulator for creating personalized brain models using SC and FC. The aim of this study was to explore SC-FC relationship in MS using TVB. Two different model regimes have been studied: stable and oscillatory, with the latter including conduction delays in the brain. The models were applied to 513 pwMS and 208 healthy controls (HC) from 7 different centers. Models were analyzed using structural damage, global diffusion properties, clinical disability, cognitive scores, and graph-derived metrics from both simulated and empirical FC. For the stable model, higher SC-FC coupling was associated with pwMS with low Single Digit Modalities Test (SDMT) score (F=3.48, P$\lt$0.05), suggesting that cognitive impairment in pwMS is associated with a higher SC-FC coupling. Differences in entropy of the simulated FC between HC, high and low SDMT groups (F=31.57, P$\lt$1e-5), show that the model captures subtle differences not detected in the empirical FC, suggesting the existence of compensatory and maladaptive mechanisms between SC and FC in MS.

Association of Early Progression Independent of Relapse Activity With Long-term Disability After a First Demyelinating Event in Multiple Sclerosis

Importance

Progression independent of relapse activity (PIRA) is the main event responsible for irreversible disability accumulation in relapsing multiple sclerosis (MS).

Objective

To investigate clinical and neuroimaging predictors of PIRA at the time of the first demyelinating attack and factors associated with long-term clinical outcomes of people who present with PIRA.

Design, Setting, and Participants

This cohort study, conducted from January 1, 1994, to July 31, 2021, included patients with a first demyelinating attack from multiple sclerosis; patients were recruited from 1 study center in Spain. Patients were excluded if they refused to participate, had alternative diagnoses, did not meet protocol requirements, had inconsistent demographic information, or had less than 3 clinical assessments.

Exposures

Exposures included (1) clinical and neuroimaging features at the first demyelinating attack and (2) presenting PIRA, ie, confirmed disability accumulation (CDA) in a free-relapse period at any time after symptom onset, within (vs after) the first 5 years of the disease (ie, early/late PIRA), and in the presence (vs absence) of new T2 lesions in the previous 2 years (ie, active/nonactive PIRA).

Main Outcomes and Measures

Expanded Disability Status Scale (EDSS) yearly increase rates since the first attack and adjusted hazard ratios (HRs) for predictors of time to PIRA and time to EDSS 6.0.

Results

Of the 1128 patients (mean [SD] age, 32.1 [8.3] years; 781 female individuals [69.2%]) included in the study, 277 (25%) developed 1 or more PIRA events at a median (IQR) follow-up time of 7.2 (4.6-12.4) years (for first PIRA). Of all patients with PIRA, 86 of 277 (31%) developed early PIRA, and 73 of 144 (51%) developed active PIRA. Patients with PIRA were slightly older, had more brain lesions, and were more likely to have oligoclonal bands than those without PIRA. Older age at the first attack was the only predictor of PIRA (HR, 1.43; 95% CI, 1.23-1.65; P < .001 for each older decade). Patients with PIRA had steeper EDSS yearly increase rates (0.18; 95% CI, 0.16-0.20 vs 0.04; 95% CI, 0.02-0.05; P < .001) and an 8-fold greater risk of reaching EDSS 6.0 (HR, 7.93; 95% CI, 2.25-27.96; P = .001) than those without PIRA. Early PIRA had steeper EDSS yearly increase rates than late PIRA (0.31; 95% CI, 0.26-0.35 vs 0.13; 95% CI, 0.10-0.16; P < .001) and a 26-fold greater risk of reaching EDSS 6.0 from the first attack (HR, 26.21; 95% CI, 2.26-303.95; P = .009).

Conclusions and Relevance

Results of this cohort study suggest that for patients with multiple sclerosis, presenting with PIRA after a first demyelinating event was not uncommon and suggests an unfavorable long-term prognosis, especially if it occurs early in the disease course.

Evaluating the use of synthetic T1-w images in new T2 lesion detection in multiple sclerosis

The assessment of disease activity using serial brain MRI scans is one of the most valuable strategies for monitoring treatment response in patients with multiple sclerosis (MS) receiving disease-modifying treatments. Recently, several deep learning approaches have been proposed to improve this analysis, obtaining a good trade-off between sensitivity and specificity, especially when using T1-w and T2-FLAIR images as inputs. However, the need to acquire two different types of images is time-consuming, costly and not always available in clinical practice. In this paper, we investigate an approach to generate synthetic T1-w images from T2-FLAIR images and subsequently analyse the impact of using original and synthetic T1-w images on the performance of a state-of-the-art approach for longitudinal MS lesion detection. We evaluate our approach on a dataset containing 136 images from MS patients, and 73 images with lesion activity (the appearance of new T2 lesions in follow-up scans). To evaluate the synthesis of the images, we analyse the structural similarity index metric and the median absolute error and obtain consistent results. To study the impact of synthetic T1-w images, we evaluate the performance of the new lesion detection approach when using (1) both T2-FLAIR and T1-w original images, (2) only T2-FLAIR images, and (3) both T2-FLAIR and synthetic T1-w images. Sensitivities of 0.75, 0.63, and 0.81, respectively, were obtained at the same false-positive rate (0.14) for all experiments. In addition, we also present the results obtained when using the data from the international MSSEG-2 challenge, showing also an improvement when including synthetic T1-w images. In conclusion, we show that the use of synthetic images can support the lack of data or even be used instead of the original image to homogenize the contrast of the different acquisitions in new T2 lesions detection algorithms.

Detection of lesions in the optic nerve with magnetic resonance imaging using a 3D convolutional neural network

BACKGROUND

Optic neuritis (ON) is one of the first manifestations of multiple sclerosis, a disabling disease with rising prevalence. Detecting optic nerve lesions could be a relevant diagnostic marker in patients with multiple sclerosis.

OBJECTIVES

We aim to create an automated, interpretable method for optic nerve lesion detection from MRI scans.

MATERIALS AND METHODS

We present a 3D convolutional neural network (CNN) model that learns to detect optic nerve lesions based on T2-weighted fat-saturated MRI scans. We validated our system on two different datasets (N = 107 and 62) and interpreted the behaviour of the model using saliency maps.

RESULTS

The model showed good performance (68.11% balanced accuracy) that generalizes to unseen data (64.11%). The developed network focuses its attention to the areas that correspond to lesions in the optic nerve.

CONCLUSIONS

The method shows robustness and, when using only a single imaging sequence, its performance is not far from diagnosis by trained radiologists with the same constraint. Given its speed and performance, the developed methodology could serve as a first step to develop methods that could be translated into a clinical setting.

Paramagnetic rims are a promising diagnostic imaging biomarker in multiple sclerosis

BACKGROUND

White matter lesions (WMLs) on brain magnetic resonance imaging (MRI) in multiple sclerosis (MS) may contribute to misdiagnosis. In chronic active lesions, peripheral iron-laden macrophages appear as paramagnetic rim lesions (PRLs).

OBJECTIVE

To evaluate the sensitivity and specificity of PRLs in differentiating MS from mimics using clinical 3T MRI scanners.

METHOD

This retrospective international study reviewed MRI scans of patients with MS (n = 254), MS mimics (n = 91) and older healthy controls (n = 217). WMLs, detected using fluid-attenuated inversion recovery MRI, were analysed with phase-sensitive imaging. Sensitivity and specificity were assessed for PRLs.

RESULTS

At least one PRL was found in 22.9% of MS and 26.1% of clinically isolated syndrome (CIS) patients. Only one PRL was found elsewhere. The identification of ⩾1 PRL was the optimal cut-off and had high specificity (99.7%, confidence interval (CI) = 98.20%-99.99%) when distinguishing MS and CIS from mimics and healthy controls, but lower sensitivity (24.0%, CI = 18.9%-36.6%). All patients with a PRL showing a central vein sign (CVS) in the same lesion (n = 54) had MS or CIS, giving a specificity of 100% (CI = 98.8%-100.0%) but equally low sensitivity (21.3%, CI = 16.4%-26.81%).

CONCLUSION

PRLs may reduce diagnostic uncertainty in MS by being a highly specific imaging diagnostic biomarker, especially when used in conjunction with the CVS.

Confirming a Historical Diagnosis of Multiple Sclerosis: Challenges and Recommendations

Patients with a historical diagnosis of multiple sclerosis (MS)-a patient presenting with a diagnosis of MS made previously and by a different clinician-present specific diagnostic and therapeutic challenges in clinical practice. Application of the McDonald criteria is most straightforward when applied contemporaneously with a syndrome typical of an MS attack or relapse; however, retrospective application of the criteria in some patients with a historical diagnosis of MS can be problematic. Limited patient recollection of symptoms and evolution of neurologic examination and MRI findings complicate confirmation of an earlier MS diagnosis and assessment of subsequent disease activity or clinical progression. Adequate records for review of prior clinical examinations, laboratory results, and/or MRI scans obtained at the time of diagnosis or during ensuing care may be inadequate or unavailable. This article provides recommendations for a clinical approach to the evaluation of patients with a historical diagnosis of MS to aid diagnostic confirmation, avoid misdiagnosis, and inform therapeutic decision making.

MAGNIMS recommendations for harmonization of MRI data in MS multicenter studies

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Sharing data from cooperative studies is essential to develop new biomarkers in MS.

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Differences in MRI acquisition, analysis, storage represent a substantial constraint.

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We review the state of the art and developments in the harmonization of MRI.

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We provide recommendations to harmonize large MRI datasets in the MS field.

There is an increasing need of sharing harmonized data from large, cooperative studies as this is essential to develop new diagnostic and prognostic biomarkers. In the field of multiple sclerosis (MS), the issue has become of paramount importance due to the need to translate into the clinical setting some of the most recent MRI achievements. However, differences in MRI acquisition parameters, image analysis and data storage across sites, with their potential bias, represent a substantial constraint. This review focuses on the state of the art, recent technical advances, and desirable future developments of the harmonization of acquisition, analysis and storage of large-scale multicentre MRI data of MS cohorts. Huge efforts are currently being made to achieve all the requirements needed to provide harmonized MRI datasets in the MS field, as proper management of large imaging datasets is one of our greatest opportunities and challenges in the coming years. Recommendations based on these achievements will be provided here. Despite the advances that have been made, the complexity of these tasks requires further research by specialized academical centres, with dedicated technical and human resources. Such collective efforts involving different professional figures are of crucial importance to offer to MS patients a personalised management while minimizing consumption of resources.

T1/T2-weighted ratio in multiple sclerosis: A longitudinal study with clinical associations

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Alterations in T1-w/T2-w ratio precede lesion formation in CIS patients.

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Longitudinal decreases in T1-w/T2-w were associated with disease activity in CIS.

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Lower T1-w/T2-w was associated with longer disease duration and higher EDSS in MS.

Background

T1w/T2-w ratio has been proposed as a clinically feasible MRI biomarker to assess tissue integrity in multiple sclerosis. However, no data is available in the earliest stages of the disease and longitudinal studies analysing clinical associations are scarce.

Objective

To describe longitudinal changes in T1-w/T2-w in patients with clinically isolated syndrome (CIS) and multiple sclerosis, and to investigate their clinical associations.

Methods

T1-w/T2-w images were generated and the mean value obtained in the corresponding lesion, normal-appearing grey (NAGM) and white matter (NAWM) masks. By co-registering baseline to follow-up MRI, evolved lesions were assessed; and by placing the mask of new lesions to the baseline study, the pre-lesional tissue integrity was measured.

Results

We included 171 CIS patients and 22 established multiple sclerosis patients. In CIS, evolved lesions showed significant T1-w/T2-w increases compared to baseline (+7.6%, P < 0.001). T1-w/T2-w values in new lesions were lower than in pre-lesional tissue (-28.2%, P < 0.001), and pre-lesional tissue was already lower than baseline NAWM (-7.8%, P < 0.001). In CIS at baseline, higher NAGM T1-w/T2-w was associated with multiple sclerosis diagnosis, and longitudinal decreases in NAGM and NAWM T1-w/T2-w were associated with disease activity. In established multiple sclerosis, T1-w/T2-w was inversely correlated with clinical disability and disease duration.

Conclusion

A decrease in T1-w/T2-w ratio precedes lesion formation. In CIS, higher T1-w/T2-w was associated with multiple sclerosis diagnosis. In established multiple sclerosis, lower T1-w/T2-w values were associated with clinical disability. The possible differential impact of chronic inflammation, iron deposition and demyelination should be considered to interpret these findings.

SWI as an Alternative to Contrast-Enhanced Imaging to Detect Acute MS Lesions

BACKGROUND AND PURPOSE

Acute inflammatory activity of MS lesions is traditionally assessed through contrast-enhanced T1-weighted MR images. The aim of our study was to determine whether a qualitative evaluation of non-contrast-enhanced SWI of new T2-hyperintense lesions might help distinguish acute and chronic lesions and whether it could be considered a possible alternative to gadolinium-based contrast agents for this purpose.

MATERIALS AND METHODS

Serial MR imaging studies from 55 patients with MS were reviewed to identify 169 new T2-hyperintense lesions. Two blinded neuroradiologists determined their signal pattern on SWI, considering 5 categories (hypointense rings, marked hypointensity, mild hypointensity, iso-/hyperintensity, indeterminate). Two different blinded neuroradiologists evaluated the presence or absence of enhancement in postcontrast T1-weighted images of the lesions. The Fisher exact test was used to determine whether each category of signal intensity on SWI was associated with gadolinium enhancement.

RESULTS

The presence of hypointense rings or marked hypointensity showed a strong association with the absence of gadolinium enhancement (P < .001), with a sensitivity of 93.0% and a specificity of 82.9%. The presence of mild hypointensity or isohyperintensity showed a strong association with the presence of gadolinium enhancement (P < .001), with a sensitivity of 68.3% and a specificity of 99.2%.

CONCLUSIONS

A qualitative analysis of the signal pattern on SWI of new T2-hyperintense MS lesions allows determining the likelihood that the lesions will enhance after administration of a gadolinium contrast agent, with high specificity albeit with a moderate sensitivity. While it cannot substitute for the use of contrast agent, it can be useful in some clinical settings in which the contrast agent cannot be administered.

Prognosis of a second clinical event from baseline MRI in patients with a CIS: a multicenter study using a machine learning approach

PURPOSE

To predict the occurrence of a second clinical event in patients with a CIS suggestive of MS, from baseline magnetic resonance imaging (MRI), by means of a pattern recognition approach.

METHODS

Two hundred sixty-six patients with a CIS were recruited from four participating centers. Over a follow-up of 3 years, 130 patients had a second clinical episode and 136 did not. Grey matter and white matter T1-hypointensities masks segmented from 3D T1-weighted images acquired on 3 T scanners were used as features for the classification approach. Differences between CIS that remained CIS and those that developed a second event were assessed at a global level and at a regional level, arranging the regions according to their contribution to the classification model.

RESULTS

All classification metrics were around or even below 50% for both global and regional approaches. Accuracies did not change when T1-hypointensity maps were added to the model; just the specificity was increased up to 80%. Among the 30 regions with the largest contribution, 26 were grey matter and 4 were white matter regions. For grey matter, regions contributing showed either a larger or a smaller volume in the group of patients that remained CIS, compared to those with a second event. The volume of T1-hypointensities was always larger for the group that presented a second event.

CONCLUSIONS

Prediction of a second clinical event in CIS patients from baseline MRI seems to present a highly heterogeneous pattern, leading to very low classification accuracies. Adding the T1-hypointensity maps does not seem to improve the accuracy of the classification model.

Recommendations for the Diagnosis and Treatment of Multiple Sclerosis Relapses

Minimizing the risk of relapse is essential in multiple sclerosis (MS). As none of the treatments currently available are capable of completely preventing relapses, treatment of these episodes remains a cornerstone of MS care. The objective of this manuscript is to reduce uncertainty and improve quality of care of this neurological process. This article addresses definitions of key concepts, recommendations for clinical examination, classification criteria, magnetic resonance imaging, biomarkers, and specific therapeutic counsels including special populations such as pregnant and breastfeeding women, and children. An algorithm for treating MS relapses is also provided.

Effect of Changes in MS Diagnostic Criteria Over 25 Years on Time to Treatment and Prognosis in Patients With Clinically Isolated Syndrome

BACKGROUND AND OBJECTIVES

To explore whether time to diagnosis, time to treatment initiation, and age to reach disability milestones have changed in patients with clinically isolated syndrome (CIS) according to different multiple sclerosis (MS) diagnostic criteria periods.

METHODS

This retrospective study was based on data collected prospectively from the Barcelona-CIS cohort between 1994 and 2020. Patients were classified into 5 periods according to different MS criteria, and the times to MS diagnosis and treatment initiation were evaluated. The age at which patients with MS reached an Expanded Disability Status Scale (EDSS) score ≥3.0 was assessed by Cox regression analysis according to diagnostic criteria periods. Last, to remove the classic Will Rogers phenomenon by which the use of different MS criteria over time might result in a changes of prognosis, the 2017 McDonald criteria were applied, and age at EDSS score ≥3.0 was assessed by Cox regression.

RESULTS

In total, 1,174 patients were included. The median time from CIS to MS diagnosis and from CIS to treatment initiation showed a 77% and 82% reduction from the Poser to the McDonald 2017 diagnostic criteria periods, respectively. Patients of a given age diagnosed in more recent diagnostic criteria periods had a lower risk of reaching an EDSS score ≥3.0 than patients of the same age diagnosed in earlier diagnostic periods (reference category Poser period): adjusted hazard ratio (aHR) 0.47 (95% confidence interval 0.24-0.90) for McDonald 2001, aHR 0.25 (0.12-0.54) for McDonald 2005, aHR 0.30 (0.12-0.75) for McDonald 2010, and aHR 0.07 (0.01-0.45) for McDonald 2017. Patients in the early-treatment group displayed an aHR of 0.53 (0.33-0.85) of reaching age at EDSS score ≥3.0 compared to those in the late-treatment group. Changes in prognosis together with early-treatment effect were maintained after the exclusion of possible bias derived from the use of different diagnostic criteria over time (Will Rogers phenomenon).

DISCUSSION

A continuous decrease in the time to MS diagnosis and treatment initiation was observed across diagnostic criteria periods. Overall, patients diagnosed in more recent diagnostic criteria periods displayed a lower risk of reaching disability. The prognostic improvement is maintained after the Will Rogers phenomenon is discarded, and early treatment appears to be the most likely contributing factor.

Open-access quantitative MRI data of the spinal cord and reproducibility across participants, sites and manufacturers

In a companion paper by Cohen-Adad et al. we introduce the spine generic quantitative MRI protocol that provides valuable metrics for assessing spinal cord macrostructural and microstructural integrity. This protocol was used to acquire a single subject dataset across 19 centers and a multi-subject dataset across 42 centers (for a total of 260 participants), spanning the three main MRI manufacturers: GE, Philips and Siemens. Both datasets are publicly available via git-annex. Data were analysed using the Spinal Cord Toolbox to produce normative values as well as inter/intra-site and inter/intra-manufacturer statistics. Reproducibility for the spine generic protocol was high across sites and manufacturers, with an average inter-site coefficient of variation of less than 5% for all the metrics. Full documentation and results can be found at https://spine-generic.rtfd.io/ . The datasets and analysis pipeline will help pave the way towards accessible and reproducible quantitative MRI in the spinal cord.

Quantification of Cervical Cord Cross-Sectional Area: Which Acquisition, Vertebra Level, and Analysis Software? A Multicenter Repeatability Study on a Traveling Healthy Volunteer

Background: Considerable spinal cord (SC) atrophy occurs in multiple sclerosis (MS). While MRI-based techniques for SC cross-sectional area (CSA) quantification have improved over time, there is no common agreement on whether to measure at single vertebral levels or across larger regions and whether upper SC CSA can be reliably measured from brain images. Aim: To compare in a multicenter setting three CSA measurement methods in terms of repeatability at different anatomical levels. To analyze the agreement between measurements performed on the cervical cord and on brain MRI. Method: One healthy volunteer was scanned three times on the same day in six sites (three scanner vendors) using a 3T MRI protocol including sagittal 3D T1-weighted imaging of the brain (covering the upper cervical cord) and of the SC. Images were analyzed using two semiautomated methods [NeuroQLab (NQL) and the Active Surface Model (ASM)] and the fully automated Spinal Cord Toolbox (SCT) on different vertebral levels (C1-C2; C2/3) on SC and brain images and the entire cervical cord (C1-C7) on SC images only. Results: CSA estimates were significantly smaller using SCT compared to NQL and ASM (p < 0.001), regardless of the cord level. Inter-scanner repeatability was best in C1-C7: coefficients of variation for NQL, ASM, and SCT: 0.4, 0.6, and 1.0%, respectively. CSAs estimated in brain MRI were slightly lower than in SC MRI (all p ≤ 0.006 at the C1-C2 level). Despite protocol harmonization between the centers with regard to image resolution and use of high-contrast 3D T1-weighted sequences, the variability of CSA was partly scanner dependent probably due to differences in scanner geometry, coil design, and details of the MRI parameter settings. Conclusion: For CSA quantification, dedicated isotropic SC MRI should be acquired, which yielded best repeatability in the entire cervical cord. In the upper part of the cervical cord, use of brain MRI scans entailed only a minor loss of CSA repeatability compared to SC MRI. Due to systematic differences between scanners and the CSA quantification software, both should be kept constant within a study. The MRI dataset of this study is available publicly to test new analysis approaches.