Magnetic Resonance Imaging in Primary Progressive Multiple Sclerosis Patients : Review

Contrast Agent-Specific Parameter Optimization for T1-Weighted Fast Spoiled Gradient Echo Imaging: Use Cases for Gadoterate Meglumine and Gadobutrol at 1.5T and 3.0T

OBJECTIVES

The objective of this study is to derive a contrast agent-specific theoretical framework to optimize acquisition parameters for contrast-enhanced magnetic resonance imaging (MRI) based on the physiochemical properties of gadolinium-based contrast agents, focusing on fast spoiled gradient recalled echo sequences. The goal is to enhance the lesion-to-background contrast for improved diagnostic sensitivity in clinical applications.

MATERIALS AND METHODS

Signal equations for fast spoiled gradient recalled echo sequences were derived for nonenhancing and enhancing tissues using gadoterate meglumine and gadobutrol, characterized by distinct longitudinal (r1) and transverse (r2/r*2) relaxivities. Simulations were conducted at 2 field strengths, 1.5T and 3.0T, and various scenarios were considered, including hypothetical lesions with T1 ratios ranging from 1.1 to 1.8. The signal behavior was analyzed across a range of initial conditions, including different spin densities and field-strength dependent variations in tissue relaxation times. The optimal flip angle and repetition time combinations were determined to maximize contrast. In vivo validation was performed on 2 patients undergoing contrast-enhanced MRI of the brain, using the proposed acquisition parameters.

RESULTS

The modeling and simulations revealed that the flip angle that maximizes signal intensity for a contrast-enhancing lesion (Ernst angle) differs from the flip angle that maximizes T1-dependent contrast between lesion and healthy tissue in unenhanced MRI (Pelc angle) and also differs from the flip angle that maximizes the same in contrast-enhanced MRI. The theoretical simulations indicated possible contrast gains of 24%-28% using optimized parameters. The in vivo acquisitions demonstrated contrast gains of 19%-44% for a diffuse enhancing lesion and 91% for a weakly enhancing focal lesion, when comparing the optimized acquisition parameters to manufacturer's default settings.

CONCLUSIONS

Adjusted repetition time and flip angle values, derived using the proposed framework, improved the image contrast between healthy and diseased tissues, enhancing the visualization of abnormalities. This approach can be used to optimize routine clinical MRI protocols and balance scan time with contrast enhancement. This may translate to more precise lesion detection, potentially leading to earlier and more accurate diagnosis or treatment monitoring in clinical practice.

Diffusion- and Tractography-Based Characterization of Tissue Damage Within and Surrounding Paramagnetic Rim Lesions in Multiple Sclerosis

BACKGROUND AND PURPOSE

Paramagnetic rim lesions (PRLs) are an imaging biomarker of chronic inflammation in MS that are associated with more aggressive disease. However, the precise tissue characteristics and extent of their damage, particularly with regard to connected axonal tracts, are incompletely understood. Quantitative diffusion tissue measurements and fiber tractography can provide a more complete picture of these phenomena.

MATERIALS AND METHODS

One hundred fifteen people with MS were enrolled in this study. Quantitative susceptibility mapping and DWI were acquired on a 3T MRI scanner. PRLs were identified in 49 (43%) subjects. Diffusion tractography was then used to identify nearby PRL-connected versus non-PRL connected tracts and PRL-connected versus nonconnected surrounding tracts. DWI metrics, including fractional anisotropy (FA), quantitative anisotropy (QA), mean diffusivity, axial diffusivity, radial diffusivity, isotropy, and restricted diffusion imaging, were compared between these tracts and within PRLs and non-PRL lesions themselves.

RESULTS

Tissue within PRLs had significantly lower FA than tissue within non-PRL T2 lesions (P = .04). Tracts connected to PRLs exhibited significantly lower FA (P < .001), higher restricted diffusion imaging (P = .02, and higher Iso values (P = .007) than tracts connected to non-PRL T2 lesions. Only QA was different between tracts connected to PRLs and nonconnected surrounding tracts (P = .003).

CONCLUSIONS

PRLs are more destructive both within themselves and to surrounding tissue. This damage appears more spatially than axonally mediated.

Primary Progressive Multiple Sclerosis-A Key to Understanding and Managing Disease Progression

Primary progressive multiple sclerosis (PPMS), the least frequent type of multiple sclerosis (MS), is characterized by a specific course and clinical symptoms, and it is associated with a poor prognosis. It requires extensive differential diagnosis and often a long-term follow-up before its correct recognition. Despite recent progress in research into and treatment for progressive MS, the diagnosis and management of this type of disease still poses a challenge. Considering the modern concept of progression "smoldering" throughout all the stages of disease, a thorough exploration of PPMS may provide a better insight into mechanisms of progression in MS, with potential clinical implications. The goal of this study was to review the current evidence from investigations of PPMS, including its background, clinical characteristics, potential biomarkers and therapeutic opportunities. Processes underlying CNS damage in PPMS are discussed, including chronic immune-mediated inflammation, neurodegeneration, and remyelination failure. A review of potential clinical, biochemical and radiological biomarkers is presented, which is useful in monitoring and predicting the progression of PPMS. Therapeutic options for PPMS are summarized, with approved therapies, ongoing clinical trials and future directions of investigations. The clinical implications of findings from PPMS research would be associated with reliable assessments of disease outcomes, improvements in individualized therapeutic approaches and, hopefully, novel therapeutic targets, relevant for the management of progression.

The impact of image contrast, resolution and reader expertise on black hole identification in Multiple Sclerosis

OBJECTIVES

In the neuroradiological work-up of Multiple Sclerosis (MS), the detection of "black holes" (BH) represent an information of undeniable importance. Nevertheless, different sequences can be used in clinical practice to evaluate BH in MS. Aim of this study was to investigate the possible impact of different sequences, resolutions, and levels of expertise on the intra- and inter-rater reliability identification of BH in MS.

METHODS

Brain MRI scans of 85 MS patients (M/F = 22/63; mean age = 36.0 ± 10.2 years) were evaluated in this prospective single-center study. The acquisition protocol included a 3 mm SE-T1w sequence, a 1 mm 3D-GrE-T1w sequence from which a resliced 3 mm sequence was also obtained. Images were evaluated independently by two readers of different expertise at baseline and after a wash-out period of 30 days. The intraclass correlation coefficient (ICC) was calculated as an index of intra and inter-reader reliability.

RESULTS

For both readers, the intra-reader ICC analysis showed that the 3 mm SE-T1w and 3 mm resliced GrE-T1w images achieved an excellent performance (both with an ICC ≥ 0.95), while 1 mm 3D-GrE-T1w scans achieved a moderate one (ICC < 0.90). The inter-reader analysis showed that each of the three sequences achieved a moderate performance (all ICCs < 0.90).

CONCLUSIONS

The 1 mm 3D-GrE-T1w sequence seems to be prone to a greater intra-reader variability compared to the 3 mm SE-T1w, with this effect being driven by the higher spatial resolution of the first sequence. To ensure reliability levels comparable with the standard SE-T1w in BH count, an assessment on a 3 mm resliced GrE-T1w sequence should be recommended.

Mapping brain volume change across time in primary-progressive multiple sclerosis

PURPOSE

Detection and prediction of the rate of brain volume loss with age is a significant unmet need in patients with primary progressive multiple sclerosis (PPMS). In this study we construct detailed brain volume maps for PPMS patients. These maps compare age-related changes in both cortical and sub-cortical regions with those in healthy individuals.

METHODS

We conducted retrospective analyses of brain volume using T1-weighted Magnetic Resonance Imaging (MRI) scans of a large cohort of PPMS patients and healthy subjects. The volume of brain parenchyma (BP), cortex, white matter (WM), deep gray matter, thalamus, and cerebellum were measured using the robust SynthSeg segmentation tool. Age- and gender-related regression curves were constructed based on data from healthy subjects, with the 95% prediction interval adopted as the normality threshold for each brain region.

RESULTS

We analyzed 495 MRI scans from 169 PPMS patients, aged 20-79 years, alongside 563 exams from healthy subjects aged 20-86. Compared to healthy subjects, a higher proportion of PPMS patients showed lower than expected brain volumes in all regions except the cerebellum. The most affected areas were BP, WM, and thalamus. Lower brain volumes correlated with longer disease duration for BP and WM, and higher disability for BP, WM, cortex, and thalamus.

CONCLUSIONS

Constructing age- and gender-related brain volume maps enabled identifying PPMS patients at a higher risk of brain volume loss. Monitoring these high-risk patients may lead to better treatment decisions and improve patient outcomes.

Advanced MRI Techniques: Diagnosis and Follow-Up of Multiple Sclerosis

Brain and spinal cord imaging plays a pivotal role in aiding clinicians with the diagnosis and monitoring of multiple sclerosis. Nevertheless, the significance of magnetic resonance imaging in MS extends beyond its clinical utility. Advanced imaging modalities have facilitated the in vivo detection of various components of MS pathogenesis, and, in recent years, MRI biomarkers have been utilized to assess the response of patients with relapsing-remitting MS to the available treatments. Similarly, MRI indicators of neurodegeneration demonstrate potential as primary and secondary endpoints in clinical trials targeting progressive phenotypes. This review aims to provide an overview of the latest advancements in brain and spinal cord neuroimaging in MS.

Multiple Sclerosis: An Emergency Medicine-Focused Narrative Review

BACKGROUND

Multiple sclerosis (MS) is a rare but serious condition associated with significant morbidity.

OBJECTIVE

This review provides a focused assessment of MS for emergency clinicians, including the presentation, evaluation, and emergency department (ED) management based on current evidence.

DISCUSSION

MS is an autoimmune disorder targeting the central nervous system (CNS), characterized by clinical relapses and radiological lesions disseminated in time and location. Patients with MS most commonly present with long tract signs (e.g., myelopathy, asymmetric spastic paraplegia, urinary dysfunction, Lhermitte's sign), optic neuritis, or brainstem syndromes (bilateral internuclear ophthalmoplegia). Cortical syndromes or multifocal presentations are less common. Radiologically isolated syndrome and clinically isolated syndrome (CIS) may or may not progress to chronic forms of MS, including relapsing remitting MS, primary progressive MS, and secondary progressive MS. The foundation of outpatient management involves disease-modifying therapy, which is typically initiated with the first signs of disease onset. Management of CIS and acute flares of MS in the ED includes corticosteroid therapy, ideally after diagnostic testing with imaging and lumbar puncture for cerebrospinal fluid analysis. Emergency clinicians should evaluate whether patients with MS are presenting with new-onset debilitating neurological symptoms to avoid unnecessary testing and admissions, but failure to appropriately diagnose CIS or MS flare is associated with increased morbidity.

CONCLUSIONS

An understanding of MS can assist emergency clinicians in better diagnosing and managing this neurologically devastating disease.

Multiple sclerosis versus cerebral small vessel disease in MRI: a practical approach using qualitative and quantitative signal intensity differences in white matter lesions

BACKGROUND

Multiple sclerosis (MS) and cerebral small vessel disease (CSVD) are relatively common radiological entities that occasionally necessitate differential diagnosis.

PURPOSE

To investigate the differences in magnetic resonance imaging (MRI) signal intensity (SI) between MS and CSVD related white matter lesions.

MATERIAL AND METHODS

On 1.5-T and 3-T MRI scanners, 50 patients with MS (380 lesions) and 50 patients with CSVD (395 lesions) were retrospectively evaluated. Visual inspection was used to conduct qualitative analysis on diffusion-weighted imaging (DWI)_b1000 to determine relative signal intensity. The thalamus served as the reference for quantitative analysis based on SI ratio (SIR). The statistical analysis utilized univariable and multivariable methods. There were analyses of patient and lesion datasets. On a dataset restricted by age (30-50 years), additional evaluations, including unsupervised fuzzy c-means clustering, were performed.

RESULTS

Using both quantitative and qualitative features, the optimal model achieved a 100% accuracy, sensitivity, and specificity with an area under the curve (AUC) of 1 in patient-wise analysis. With an AUC of 0.984, the best model achieved a 94% accuracy, sensitivity, and specificity when using only quantitative features. The model's accuracy, sensitivity, and specificity were 91.9%, 84.6%, and 95.8%, respectively, when using the age-restricted dataset. Independent predictors were T2_SIR_max (optimal cutoff=2.1) and DWI_b1000_SIR_mean (optimal cutoff=1.1). Clustering also performed well with an accuracy, sensitivity, and specificity of 86.5%, 70.6%, and 100%, respectively, in the age-restricted dataset.

CONCLUSION

SI characteristics derived from DWI_b1000 and T2-weighted-based MRI demonstrate excellent performance in differentiating white matter lesions caused by MS and CSVD.

Diffusion-based structural connectivity patterns of multiple sclerosis phenotypes

BACKGROUND

We aimed to describe the severity of the changes in brain diffusion-based connectivity as multiple sclerosis (MS) progresses and the microstructural characteristics of these networks that are associated with distinct MS phenotypes.

METHODS

Clinical information and brain MRIs were collected from 221 healthy individuals and 823 people with MS at 8 MAGNIMS centres. The patients were divided into four clinical phenotypes: clinically isolated syndrome, relapsing-remitting, secondary progressive and primary progressive. Advanced tractography methods were used to obtain connectivity matrices. Then, differences in whole-brain and nodal graph-derived measures, and in the fractional anisotropy of connections between groups were analysed. Support vector machine algorithms were used to classify groups.

RESULTS

Clinically isolated syndrome and relapsing-remitting patients shared similar network changes relative to controls. However, most global and local network properties differed in secondary progressive patients compared with the other groups, with lower fractional anisotropy in most connections. Primary progressive participants had fewer differences in global and local graph measures compared with clinically isolated syndrome and relapsing-remitting patients, and reductions in fractional anisotropy were only evident for a few connections. The accuracy of support vector machine to discriminate patients from healthy controls based on connection was 81%, and ranged between 64% and 74% in distinguishing among the clinical phenotypes.

CONCLUSIONS

In conclusion, brain connectivity is disrupted in MS and has differential patterns according to the phenotype. Secondary progressive is associated with more widespread changes in connectivity. Additionally, classification tasks can distinguish between MS types, with subcortical connections being the most important factor.

An Atypical Presentation of Progressive Multiple Sclerosis in a Young Black Male

Multiple sclerosis (MS) is an autoimmune disease primarily affecting the central nervous system, commonly diagnosed in women and individuals of European ancestry. It most commonly presents in the form of relapsing-remitting MS, which is characterized by exacerbations with partial to complete recovery. Far less common is the primary progressive form of MS, which involves the progression of neurological symptoms that gradually worsen with time. We present an atypical case of progressive MS in a 26-year-old incarcerated Black male. Initially diagnosed in 2019, he experienced bilateral upper extremity weakness and phasic spasticity, with subsequent worsening of symptoms including lower extremity spasticity, vision impairment, and difficulties with mobility and writing. With progressing symptoms, unintentional weight loss, and declining motor function, he was admitted to the hospital in March 2023. This case emphasizes the importance of considering MS as a differential diagnosis in any patient with progressive neurological dysfunction because, unlike the more prevalent relapsing-remitting type of MS, primary progressive MS has a more insidious onset with no recovery between exacerbations. It addresses the patient's symptom history, medication compliance challenges, and the need for improved education and awareness of MS in diverse patient populations.

The familial risk and heritability of multiple sclerosis and its onset phenotypes: A case-control study

BACKGROUND

The two main phenotypes of multiple sclerosis (MS), primary progressive (PPMS) and relapsing Onset (ROMS), show clinical and demographic differences suggesting possible differential risk mechanisms. Understanding the heritable features of these phenotypes could provide aetiological insight.

OBJECTIVES

To evaluate the magnitude of familial components in PPMS and ROMS and to estimate the heritability of disease phenotypes.

METHODS

We used data from 25,186 MS patients of Nordic ancestry from the Swedish MS Registry between 1987 and 2019 with known disease phenotype (1593 PPMS and 16,718 ROMS) and 251,881 matched population-based controls and 3,364,646 relatives of cases and controls. Heritability was calculated using threshold-liability models. For familial odds ratios (ORs), logistic regression with robust sandwich estimator was utilized.

RESULTS

The OR of MS diagnosis in those with a first-degree family member with ROMS was 7.00 and 8.06 in those with PPMS. The corresponding ORs for having a second-degree family member with ROMS was 2.16 and 2.18 in PPMS. The additive genetic effect in ROMS was 0.54 and 0.22 in PPMS.

CONCLUSION

Risk of MS increases by several folds in those with a relative with MS. The likelihood of developing either disease phenotype appears independent of genetic predisposition.

Comparison of recent updates in genetics, immunology, biomarkers, and neuroimaging of primary-progressive and relapsing-remitting multiple sclerosis and the role of ocrelizumab in the management of their refractory cases

Background

Primary-progressive multiple sclerosis (PPMS) and relapsing-remitting multiple sclerosis (RRMS) are two frequent multiple sclerosis (MS) subtypes that involve 10%-15% of patients. PPMS progresses slowly and is diagnosed later in life. Both subtypes are influenced by genetic and environmental factors such as smoking, obesity, and vitamin D insufficiency. Although there is no cure, ocrelizumab can reduce symptoms and delay disease development. RRMS is an autoimmune disease that causes inflammation, demyelination, and disability. Early detection, therapy, and lifestyle changes are critical. This study delves into genetics, immunology, biomarkers, neuroimaging, and the usefulness of ocrelizumab in the treatment of refractory patients of PPMS.

Method

In search of published literature providing up-to-date information on PPMS and RRMS, this review conducted numerous searches in databases such as PubMed, Google Scholar, MEDLINE, and Scopus. We looked into genetics, immunology, biomarkers, current breakthroughs in neuroimaging, and the role of ocrelizumab in refractory cases.

Results

Our comprehensive analysis found considerable advances in genetics, immunology, biomarkers, neuroimaging, and the efficacy of ocrelizumab in the treatment of refractory patients.

Conclusion

Early detection, timely intervention, and the adoption of lifestyle modifications play pivotal roles in enhancing treatment outcomes. Notably, ocrelizumab has demonstrated potential in symptom control and mitigating the rate of disease advancement, further underscoring its clinical significance in the management of MS.

Triggering multiple sclerosis at conception and early gestation: The variation in ultraviolet radiation is as important as its intensity

Background and objectives

Medical science needs to further elucidate the role of ultraviolet radiation (UVR), geographic latitude, and the role of vitamin D in the autoimmune disease multiple sclerosis (MS). We separated several papers into categories out of the thousands published and used their conclusions to explore the relationship between UVR and MS.

Relevance

MS is increasing in incidence, particularly in women where MS is two to three times that in men and particularly severe in African Americans.

Methods

We collected UVR data at our observatory in Central Maine and calculated the average coefficient of variation (CVUVR) for each month for 15 years (2007-2021, inclusive).

Results

The month of conception (MOC) is more important than the month of birth (MOB) in explaining how UVR triggers the variable genetic predisposition to MS. We hypothesize that the rapidly increasing CVUVR is important in preventing an increase in the activity of the vitamin D receptor (VDR) from August to December, which then requires a higher intensity of UVR later in life to suppress the immune system, therefore predisposing to more MS.

Limitations

One observatory at about 44° latitude.

Conclusions

While variation in UVR is important at the MOC if UVR exceeds a threshold (e.g., if the sunspot number equals or is greater than 90, usually at a solar cycle MAX, or at elevations above approximately 3,000 feet above sea level), the MS mitigating vitamin D-VDR mechanism is overwhelmed and the genotoxic effects of higher-intensity UVR promote MS in those with a genetic predisposition.

What is new in this research

This paper offers a new concept in MS research.

Arginine vasopressin hormone receptor antagonists in experimental autoimmune encephalomyelitis rodent models: A new approach for human multiple sclerosis treatment

Multiple sclerosis (MS) is a chronic demyelinating and neurodegenerative disease that affects the central nervous system. MS is a heterogeneous disorder of multiple factors that are mainly associated with the immune system including the breakdown of the blood-brain and spinal cord barriers induced by T cells, B cells, antigen presenting cells, and immune components such as chemokines and pro-inflammatory cytokines. The incidence of MS has been increasing worldwide recently, and most therapies related to its treatment are associated with the development of several secondary effects, such as headaches, hepatotoxicity, leukopenia, and some types of cancer; therefore, the search for an effective treatment is ongoing. The use of animal models of MS continues to be an important option for extrapolating new treatments. Experimental autoimmune encephalomyelitis (EAE) replicates the several pathophysiological features of MS development and clinical signs, to obtain a potential treatment for MS in humans and improve the disease prognosis. Currently, the exploration of neuro-immune-endocrine interactions represents a highlight of interest in the treatment of immune disorders. The arginine vasopressin hormone (AVP) is involved in the increase in blood−brain barrier permeability, inducing the development and aggressiveness of the disease in the EAE model, whereas its deficiency improves the clinical signs of the disease. Therefore, this present review discussed on the use of conivaptan a blocker of AVP receptors type 1a and type 2 (V1a and V2 AVP) in the modulation of immune response without completely depleting its activity, minimizing the adverse effects associated with the conventional therapies becoming a potential therapeutic target in the treatment of patients with multiple sclerosis.

T2-fluid attenuated inversion recovery mismatch in tumefactive multiple sclerosis

The T2-fluid attenuated inversion recovery (FLAIR) mismatch sign has been suggested as an imaging marker of isocitrate dehydrogenase-mutant 1p/19q non-codeleted gliomas with 100% specificity. Tumefactive demyelination is a common mimic of neoplasm that has led to unnecessary biopsies and even resections. We report a case of tumefactive multiple sclerosis in a 46-year-old male without prior symptomatic demyelinating episodes that demonstrates the T2-FLAIR mismatch sign. Our findings suggest the T2-FLAIR mismatch sign should not be used as a differential feature between glioma and tumefactive demyelination. Because typical isocitrate dehydrogenase-mutant 1p/19q non-codeleted gliomas typically do not demonstrate significant enhancement, such diagnosis should be reserved when post-contrast images are unavailable.