Neurological research in Italy from 2020 to 2023

BACKGROUND

To assess the state of neurological scientific research in Italy in the time interval 2020-2023.

METHODS

Elsevier's modular integrated platform "SciVal" was used to analyze bibliometric research products starting from scientific production data uploaded onto Scopus. We considered the research area "Neurology" in the 01/01/2020-14/06/2023 time interval, and the following variables were extracted: number of published studies, number of citations, Field-Weighted Citation Impact, and percentage of international collaborations. The contribution of Italian scientists to the neurological research was compared to that of the other nations.

RESULTS

Research identified 90,633 scientific papers in the neurological area worldwide, with a total of 472,750 citations. The products assigned to Italian groups were 6670 (53,587 citations, Field-Weighted Citation Impact 1.68, 41% international collaborations).

CONCLUSIONS

According to the present study, Italian neurological research 2020 to 2023 ranks fifth globally and third in Europe.

Temporal evolution of new T1-weighted hypo-intense lesions and central brain atrophy in patients with a first clinical demyelinating event treated with subcutaneous interferon β-1a

OBJECTIVE

Evaluate the effect of subcutaneous interferon β-1a (sc IFN β-1a) versus placebo on the evolution of T1-weighted MRI lesions and central brain atrophy in in patients with a first clinical demyelinating event (FCDE).

METHODS

Post hoc analysis of baseline-to-24 month MRI data from patients with an FCDE who received sc IFN β-1a 44 μg once- (qw) or three-times-weekly (tiw), or placebo, in REFLEX. Patients were grouped according to treatment regimen or conversion to clinically definite MS (CDMS) status. The intensity of new lesions on unenhanced T1-weighted images was classified as T1 iso- or hypo-intense (black holes) and percentage ventricular volume change (PVVC) was assessed throughout the study.

RESULTS

In patients not converting to CDMS, sc IFN β-1a tiw or qw, versus placebo, reduced the overall number of new lesions (P < 0.001 and P = 0.005) and new T1 iso-intense lesions (P < 0.001 and P = 0.002) after 24 months; only sc IFN β-1a tiw was associated with fewer T1 hypo-intense lesions versus placebo (P < 0.001). PVVC findings in patients treated with sc IFN β-1a suggested pseudo-atrophy that was ~ fivefold greater versus placebo in the first year of treatment (placebo 1.11%; qw 4.28%; tiw 6.76%; P < 001); similar findings were apparent for non-converting patients.

CONCLUSIONS

In patients with an FCDE, treatment with sc IFN β-1a tiw for 24 months reduced the number of new lesions evolving into black holes.

Peak width of skeletonized mean diffusivity (PSMD) as marker of widespread white matter tissue damage in multiple sclerosis

BACKGROUND

Peak width of skeletonized mean diffusivity (PSMD) is a novel and fully automated, MRI biomarker, which has shown clinical relevance in cerebral small vessel diseases (SVD). We aimed here to assess PSMD levels across the brain of patients with multiple sclerosis (MS), in comparison to normal controls (NC) and patients with CADASIL, a genetically defined form of severe SVD.

METHODS

We assessed PSMD in relapsing-remitting (RR) MS patients (n = 47) in comparison to age-matched CADASIL patients (n = 25) and NC (n = 28). Diffusion Tensor Imaging data were acquired on 1.5T MR clinical scanner to automatically compute PSMD through "skeletonization" of WM tracts and diffusion histograms.

RESULTS

RRMS had lower WM lesion volume (LV) than CADASIL (8.6 ± 8.2 vs 24.4 ± 17.4 cm³, p < 0.001). After correction for LV, PSMD values in MS were higher than in CADASIL patients (adjusted mean values: 4.5 vs 3.9 × 10^-4 mm²/s, p = 0.03) and in both patient groups were higher than in NC (2.8 ± 0.3 × 10^-4 mm²/s, p < 0.001). PSMD values correlated with LV in both patient groups (r = 0.8, p < 0.001 in MS; r = 0.6, p = 0.002 in CADASIL).

CONCLUSIONS

In both patient groups, PSMD was higher than in NC and closely correlated with LV, suggesting sensitivity in assessing brain tissue damage in these disorders. In MS patients, PSMD levels were higher than in CADASIL patients, despite the lower LV. This might be related to more severe normal-appearing WM abnormalities occurring in the MS brains. This novel, fully automated, MRI metric may represent a useful marker for a robust quantification of the diffuse WM tissue damage in MS.

Subclinical motor impairment assessed with an engineered glove correlates with magnetic resonance imaging tissue damage in radiologically isolated syndrome

BACKGROUND

An engineered glove measuring finger motor performance previously showed ability to discriminate early-stage multiple sclerosis (MS) patients from healthy controls (HCs). Radiologically isolated syndrome (RIS) classifies asymptomatic subjects with brain magnetic resonance imaging (MRI) abnormalities suggestive of multiple sclerosis.

METHODS

Seventeen asymptomatic subjects with RIS and 17 HCs were assessed. They performed finger-to-thumb opposition sequences at their maximal velocity, metronome-paced bimanual movements and conventional and diffusion tensor MRI.

RESULTS

Subjects with RIS showed lower (P = 0.005) maximal velocity and higher (P = 0.006) bimanual coordination impairment than HCs. In RIS, bimanual coordination correlated with T2-lesion volume, fractional anisotropy and radial diffusivity in the white matter.

CONCLUSIONS

These findings point out the relevance of fine hand measures as a robust marker of subclinical disability.

Uso della risonanza magnetica spettroscopica del protone nello studio delle malattie della sostanza bianca cerebrale

La risonanza magnetica spettroscopica (MRS) è una tecnica non invasiva per la misura della concentrazione relativa di alcuni composti cerebrali. L'uso di questa tecnica nello studio delle malattie della materia bianca cerebrale ha apportato miglioramenti nella classificazione diagnostica e nelle misure relative all'andamento delle malattie.

Un uso più estensivo delle tecniche di risonanza multimodale, comprendenti tomografia RM, spettroscopia ed altre modalità non convenzionali, dovrebbe quindi essere incoraggiato. Ciò permetterà una miglior comprensione della complessa dinamica dei cambiamenti patologici nelle malattie della sostanza bianca ed una più accurata valutazione della progressione e della risposta alla terapia della malattia stessa.

A Semiautomatic Method for Multiple Sclerosis Lesion Segmentation on Dual-Echo MR Imaging: Application in a Multicenter Context

BACKGROUND AND PURPOSE

The automatic segmentation of MS lesions could reduce time required for image processing together with inter- and intraoperator variability for research and clinical trials. A multicenter validation of a proposed semiautomatic method for hyperintense MS lesion segmentation on dual-echo MR imaging is presented.

MATERIALS AND METHODS

The classification technique used is based on a region-growing approach starting from manual lesion identification by an expert observer with a final segmentation-refinement step. The method was validated in a cohort of 52 patients with relapsing-remitting MS, with dual-echo images acquired in 6 different European centers.

RESULTS

We found a mathematic expression that made the optimization of the method independent of the need for a training dataset. The automatic segmentation was in good agreement with the manual segmentation (dice similarity coefficient = 0.62 and root mean square error = 2 mL). Assessment of the segmentation errors showed no significant differences in algorithm performance between the different MR scanner manufacturers (P > .05).

CONCLUSIONS

The method proved to be robust, and no center-specific training of the algorithm was required, offering the possibility for application in a clinical setting. Adoption of the method should lead to improved reliability and less operator time required for image analysis in research and clinical trials in MS.

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.

PARTIAL INDEPENDENCE OF FINGOLIMOD EFFECT ON DIFFUSE VS. FOCAL DAMAGE

Objective

To investigate if the effects of fingolimod 0.5mg on brain volume loss are mediated through effects on focal disease activity (FD) or independent-reduction of diffuse damage (DD).

Methods

FREEDOMS and FREEDOMS-II data was pooled and analyzed post-hoc. Assessment of the percent brain volume change (PBVC) at M12 and 24, in patients with no evidence of FD, (absence of new Gd+ T1-lesions and/or new/enlarging T2-lesions) and clinical relapses. Regression analysis of the intent-to-treat (ITT) population to quantified whether the extent of the treatment effect was maintained for patients with new/active lesions and relapses

Results

Of the 1383 patients included, 808 patients (placebo=142; fingolimod=666) showed no FD at M12 and 573 patients (placebo=79; fingolimod=494) at M24 showed no FD. Fingolimod significantly reduced PBVC by 52% and 42% vs. placebo, over 12M and 24M respectively. In the pooled ITT population, fingolimod reduced 49% of PBVC (p<0.001)vs placebo over 24M. This effect was still evident when adjusting for new-active lesions and relapse activity (28% reduction vs placebo, p<0.001). The regression model suggests 57% of fingolimod effect on PBVC is FD-independent. Fingolimod effect on DD is partly independent of its treatment effect on FD, suggesting fingolimod impacts both inflammatory and neurodegenerative components.

Fingolimod effect on brain volume loss independently contributes to its effect on disability

Background:

Brain volume loss occurs in patients with relapsing–remitting MS. Fingolimod reduced brain volume loss in three phase 3 studies.

Objective:

To evaluate whether the effect of fingolimod on disability progression was mediated by its effects on MRI lesions, relapses or brain volume loss, and the extent of this effect.

Methods:

Patients (992/1272; 78%) from the FTY720 Research Evaluating Effects of Daily Oral Therapy in Multiple Sclerosis (FREEDOMS) study were analyzed. Month-24 percentage brain volume change, month-12 MRI-active lesions and relapse were assessed. The Prentice criteria were used to test surrogate marker validity. The proportion of treatment effect on disability progression explained by each marker was calculated.

Results:

Two-year disability progression was associated with active T2 lesions (OR = 1.24; p = 0.001) and more relapses during year 1 (OR = 2.90; p < 0.001) and lower percentage brain volume change over two years (OR = 0.78; p < 0.001). Treatment effect on active T2 lesions, relapses and percentage brain volume change explained 46%, 60% and 23% of the fingolimod effect on disability. Multivariate analysis showed the number of relapses during year 1 (OR = 2.62; p < 0.001) and yearly percentage brain volume change over two years (OR = 0.85; p = 0.009) were independent predictors of disability progression, together explaining 73% of fingolimod effect on disability.

Conclusions:

The treatment effect on relapses and, to a lesser extent, brain volume loss were both predictors of treatment effect on disability; combining these predictors better explained the effect on disability than either factor alone.

Predicting outcome in clinically isolated syndrome using machine learning

We aim to determine if machine learning techniques, such as support vector machines (SVMs), can predict the occurrence of a second clinical attack, which leads to the diagnosis of clinically-definite Multiple Sclerosis (CDMS) in patients with a clinically isolated syndrome (CIS), on the basis of single patient's lesion features and clinical/demographic characteristics.

Seventy-four patients at onset of CIS were scanned and clinically reviewed after one and three years. CDMS was used as the gold standard against which SVM classification accuracy was tested. Radiological features related to lesional characteristics on conventional MRI were defined a priori and used in combination with clinical/demographic features in an SVM. Forward recursive feature elimination with 100 bootstraps and a leave-one-out cross-validation was used to find the most predictive feature combinations.

30 % and 44 % of patients developed CDMS within one and three years, respectively. The SVMs correctly predicted the presence (or the absence) of CDMS in 71.4 % of patients (sensitivity/specificity: 77 %/66 %) at 1 year, and in 68 % (60 %/76 %) at 3 years on average over all bootstraps. Combinations of features consistently gave a higher accuracy in predicting outcome than any single feature.

Machine-learning-based classifications can be used to provide an “individualised” prediction of conversion to MS from subjects' baseline scans and clinical characteristics, with potential to be incorporated into routine clinical practice.

•

SVMs predict the presence (or absence) of a second clinical attack in Multiple Sclerosis at 1- and 3-year follow-ups.

•

SVM-based classification reaches 71.4 % accuracy, 77 % sensitivity and 66 % specificity for 1-year follow-up.

•

Combinations of features give a higher accuracy than single features.

Scoring treatment response in patients with relapsing multiple sclerosis

BACKGROUND

We employed clinical and magnetic resonance imaging (MRI) measures in combination, to assess patient responses to interferon in multiple sclerosis.

OBJECTIVE

To optimize and validate a scoring system able to discriminate responses to interferon treatment in patients with relapsing-remitting multiple sclerosis (RRMS).

METHODS

Our analysis included two large, independent datasets of RRMS patients who were treated with interferons that included 4-year follow-up data. The first dataset ("training set") comprised of 373 RRMS patients from a randomized clinical trial of subcutaneous interferon beta-1a. The second ("validation set") included an observational cohort of 222 RRMS patients treated with different interferons. The new scoring system, a modified version of that previously proposed by Rio et al., was first tested on the training set, then validated using the validation set. The association between disability progression and risk group, as defined by the score, was evaluated by Kaplan Meier survival curves and Cox regression, and quantified by hazard ratios (HRs).

RESULTS

The score (0-3) was based on the number of new T2 lesions (>5) and clinical relapses (0,1 or 2) during the first year of therapy. The risk of disability progression increased with higher scores. In the validation set, patients with score of 0 showed a 3-year progression probability of 24%, while those with a score of 1 increased to 33% (HR = 1.56; p = 0.13), and those with score greater than or equal to 2 increased to 65% (HR = 4.60; p < 0.001).

CONCLUSIONS

We report development of a simple, quantitative and complementary tool for predicting responses in interferon-treated patients that could help clinicians make treatment decisions.

Time to first relapse as an endpoint in multiple sclerosis clinical trials

Background:

The increasing number of effective therapies to treat multiple sclerosis (MS) raises ethical concerns for the use of placebo in clinical trials, suggesting that new clinical trial design strategies are needed.

Objectives:

To evaluate time to first relapse as an endpoint for MS clinical trials.

Methods:

A recently-developed model fitting the distribution of time to first relapse in MS was used for simulations estimating the sample sizes of trials using this as an outcome, and for comparison with the size of trials using the annualized relapse rate (ARR) as the primary outcome.

Results:

Trials based on time to first relapse were feasible, requiring sample sizes that were similar or even smaller than if the study was based on ARR instead. In the case of low ARR (0.4 relapses/year), as is expected in future trials, the 1-year trials designed to detect a treatment effect of 30%, with 90% power, require fewer patients when based on time to first relapse (470 patients/arm) than if based on ARR (540 patients/arm).

Conclusions:

Our simulations show that time to first relapse is not less powerful than ARR in MS trials; thus, this measure would be a potentially useful primary outcome offering the advantage of an ethically sound design, as the patients randomized to placebo can then switch to the active drug, once they relapse. A potential drawback is the loss of information for other endpoints collected at fixed time points.

Association of MRI metrics and cognitive impairment in radiologically isolated syndromes

OBJECTIVE

To evaluate cognitive changes in a cohort of radiologically isolated syndromes (RIS) suggestive of multiple sclerosis (MS) and to assess their relationship with quantitative magnetic resonance (MR) measures such as white matter (WM), lesion loads, and cerebral atrophy.

METHODS

We assessed the cognitive performance in a group of 29 subjects with RIS recruited from 5 Italian MS centers and in a group of 26 patients with relapsing-remitting MS (RRMS). A subgroup of 19 subjects with RIS, 26 patients with RRMS, and 21 healthy control (HC) subjects also underwent quantitative MR assessments, which included WM T1 and T2 lesion volumes and global and cortical brain volumes.

RESULTS

Cognitive impairment of the same profile as that of RRMS was found in 27.6% of our subjects with RIS. On MR scans, we found comparable levels of lesion loads and brain atrophy in subjects with RIS and well-established RRMS. In subjects with RIS, high T1 lesion volume (ρ = 0.526, p = 0.025) and low cortical volume (ρ = -0.481, p = 0.043) were associated with worse cognitive performance.

CONCLUSIONS

These findings emphasize the importance of including accurate neuropsychological testing and quantitative MR metrics in subjects with RIS suggestive of MS. They can provide a better characterization of these asymptomatic subjects, potentially useful for diagnostic and therapeutic decisions.

Cortical lesions in radiologically isolated syndrome

OBJECTIVE

To assess the presence of cortical lesions (CLs) as detected by MRI in subjects with radiologically isolated syndrome (RIS).

METHODS

Fifteen subjects with RIS underwent an MRI examination, including a double inversion recovery sequence for CL assessment. T2-hyperintense white matter (WM) lesion volume (LV) and normalized volumes of brain and cortex were also obtained.

RESULTS

Thirty-four CLs were identified in 6 of 15 (40%) subjects with RIS and predominantly distributed in frontotemporal lobes. CLs were frequent in subjects with RIS with immunoglobulin G oligoclonal bands on CSF, cervical cord lesions, and dissemination in time on brain MRI. WM LV was higher in subjects with CLs than in those without CLs (11.5 ± 10.1 vs 3.9 ± 2.8 cm(3), p = 0.04). Indeed, CL number and volume correlated with WM LV (r = 0.57, p = 0.03 and r = 0.61, p = 0.01). All subjects with CLs were classified in a previous study as having a very high probability of having relapsing-remitting multiple sclerosis (MS) on a logistic regression analysis of quantitative MRI indices.

CONCLUSIONS

We found CLs in subjects with RIS, a condition characterized by the unanticipated MRI finding of WM lesions highly suggestive of MS in the absence of a clinical scenario. CLs were mainly localized to the frontotemporal lobes and were associated with important markers of evolution to MS.

Combined MRI lesions and relapses as a surrogate for disability in multiple sclerosis

OBJECTIVE

In multiple sclerosis (MS), the aim of therapies is to prevent the accumulation of irreversible disability. This is difficult to assess given the short time course of clinical trials. MRI markers and relapses are often used as surrogate of disability in MS studies, but their validity remains controversial. We sought to validate, at the individual patient level, MRI lesions and relapses as surrogates for disability progression over the course of MS trials.

METHODS

Individual patient data from a large, placebo-controlled trial of interferon β-1a in relapsing-remitting MS (RRMS) were analyzed. The Prentice criteria were applied to evaluate surrogacy of 1-year MRI active lesions and relapses for disability worsening (Expanded Disability Status Scale [EDSS]) over the 2-year follow-up.

RESULTS

All Prentice criteria were satisfied. Treatment reduced by 31% the odds of having EDSS worsening over 2 years, reducing the mean number of MRI lesions by 61% and the mean number of relapses by 36% over 1 year. Both 1-year MRI lesion activity and relapses, when considered independently, accounted for more than 60% of the treatment effect on 2-year EDSS worsening. A combination of 1-year MRI lesion activity and relapses explained 100% of the treatment effect on EDSS worsening over 2 years.

CONCLUSIONS

A combined measure of 1-year changes in MRI lesions and relapses after interferon therapy fully estimated the corresponding effect on 2-year EDSS worsening. This short-term combined measure appears to be a surrogate for disability progression over a longer term when evaluating the effect of interferon in RRMS.

Pronounced focal and diffuse brain damage predicts short-term disease evolution in patients with clinically isolated syndrome suggestive of multiple sclerosis

Background: In clinically isolated syndrome (CIS), the role of quantitative magnetic resonance imaging (MRI) in detecting prognostic markers is still debated.

Objective: To evaluate measures of diffuse brain damage (such as brain atrophy and the ratio of N-acetylaspartate to creatine (NAA/Cr)) in patients with CIS, in addition to focal lesions, as predictors of 1-year disease evolution.

Methods: 49 patients with CIS underwent MRI scans to quantify T2-lesions (T2-L) and gadolinium-enhanced lesion (GEL) number at baseline and after 1 year. Along with 25 healthy volunteers, they also underwent combined MRI/magnetic resonance spectroscopy examination to measure normalized brain volumes (NBVs) and NAA/Cr. Occurrence of relapses and new T2-L was recorded over 1 year to assess disease evolution.

Results: Occurrence of relapses and/or new T2-L over 1 year divided patients with CIS into ‘active’ and ‘stable’ groups. Active patients had lower baseline NAA/Cr and NBV. Baseline T2-L number, GEL, NAA/Cr and NBV predicted subsequent disease activity. Multivariable logistic regression models showed that both ‘focal damage’ (based on T2-L number and GEL) and ‘diffuse damage’ (based on NBV and NAA/Cr) models predicted disease activity at 1 year with great sensitivity, specificity and accuracy. This was best when the four MRI measures were combined (80% sensitivity, 89% specificity, 83% accuracy).

Conclusions: Quantitative MRI measures of diffuse tissue damage such as brain atrophy and NAA/Cr, in addition to measures of focal demyelinating lesions, may predict short-term disease evolution in patients with CIS, particularly when used in combination. If confirmed in larger studies, these findings may have important clinical and therapeutic implications.

Magnetization transfer imaging demonstrates a distributed pattern of microstructural changes of the cerebral cortex in amyotrophic lateral sclerosis

BACKGROUND AND PURPOSE

To date, damage of the cerebral cortex neurons in ALS was investigated by using conventional MR imaging and proton MR spectroscopy. We explored the capability of MTI to map the microstructural changes in cerebral motor and extramotor cortices of patients with ALS.

MATERIALS AND METHODS

Twenty patients with ALS and 17 age-matched healthy controls were enrolled. A high-resolution 3D SPGR sequence with and without MT saturation pulses was obtained on a 1.5T scanner to compute MTR values. Using the FMRIB Software Library tools, we automatically computed the MTR of the cerebral cortex GM in 48 regions of the entire cerebral cortex derived from the standard Harvard-Oxford cortical atlas.

RESULTS

The MTR values were significantly lower in patients with ALS than in healthy controls in the primary motor cortex (precentral gyrus), nonprimary motor areas (superior and middle frontal gyri and superior parietal lobe), and some extramotor areas (frontal pole, planum temporale, and planum polare). No correlation was found between regional MTR values and the severity of clinical deficits or disease duration.

CONCLUSIONS

MTI analysis can detect the distributed pattern of microstructural changes of the GM in the cerebral cortex of patients with ALS with involvement of both the motor and extramotor areas.

T2 lesion location really matters: a 10 year follow-up study in primary progressive multiple sclerosis

OBJECTIVES

Prediction of long term clinical outcome in patients with primary progressive multiple sclerosis (PPMS) using imaging has important clinical implications, but remains challenging. We aimed to determine whether spatial location of T2 and T1 brain lesions predicts clinical progression during a 10-year follow-up in PPMS.

METHODS

Lesion probability maps of the T2 and T1 brain lesions were generated using the baseline scans of 80 patients with PPMS who were clinically assessed at baseline and then after 1, 2, 5 and 10 years. For each patient, the time (in years) taken before bilateral support was required to walk (time to event (TTE)) was used as a measure of progression rate. The probability of each voxel being 'lesional' was correlated with TTE, adjusting for age, gender, disease duration, centre and spinal cord cross sectional area, using a multiple linear regression model. To identify the best, independent predictor of progression, a Cox regression model was used.

RESULTS

A significant correlation between a shorter TTE and a higher probability of a voxel being lesional on T2 scans was found in the bilateral corticospinal tract and superior longitudinal fasciculus, and in the right inferior fronto-occipital fasciculus (p<0.05). The best predictor of progression rate was the T2 lesion load measured along the right inferior fronto-occipital fasciculus (p=0.016, hazard ratio 1.00652, 95% CI 1.00121 to 1.01186).

CONCLUSION

Our results suggest that the location of T2 brain lesions in the motor and associative tracts is an important contributor to the progression of disability in PPMS, and is independent of spinal cord involvement.

Magnetic resonance imaging as surrogate for clinical endpoints in multiple sclerosis: data on novel oral drugs

Recent studies have provided evidence for using magnetic resonance imaging (MRI) active lesions as surrogate for relapses and disability progression in multiple sclerosis (MS). However, the validity of MRI metrics as surrogate endpoints in MS is controversial. Furthermore, the extrapolation of previous results to novel therapies is not warranted. We tested here the validity of MRI surrogacy in MS studies on recently published trials of oral drugs. The 92% of observed effects of oral drugs on clinical outcomes resulted close to those predicted by MRI active lesions. This further validates MRI surrogacy in MS, with important implications for future trials planning.

Clinical relevance of brain volume changes in patients with cerebrotendinous xanthomatosis

OBJECTIVE

To quantify total and regional brain damage in subjects with cerebrotendinous xanthomatosis (CTX) using MR based quantitative measures.

BACKGROUND

CTX is a rare inherited disorder characterised by progressive neurological impairment. Appropriate therapy can slow disease progression. Measures of brain volume changes have been used in several neurological disorders due to their value in assessing disease outcome and monitoring patients' evolution.

METHODS

24 CTX patients underwent conventional MRI to measure total and regional brain volumes. In five CTX patients who started therapy at baseline, clinical and MRI examinations were repeated after 2 years. Clinical disability, overall cognitive performance and cerebellar function were evaluated using the modified Rankin Scale (RS), Mini Mental Status Examination (MMSE) and cerebellar functional system score (CB-FSS).

RESULTS

Measures of normalised brain, cortical and cerebellar volumes were lower in CTX patients than in healthy controls (p<0.01). Instead, there were no differences in normalised white matter volumes between the two groups (p=0.1). At regional analysis, a significant volume decrease was found in each cortical region (p<0.01 for all regions). Normalised cortical volumes correlated closely with age (r=-0.9, p<0.0001), RS (r=-0.65, p<0.001) and MMSE (r=-0.60, p<0.01). Normalised cerebellar volumes correlated closely with CB-FSS scores (r=-0.58, p<0.01). In the five CTX patients followed over time, the annual brain volume decrease was -1.1 ± 0.2%.

CONCLUSIONS

Cortical volume, rather than white matter volume, is diffusely decreased in CTX patients and correlates closely with the patient's clinical status. These data provide evidence for the presence of clinically relevant neuronal-axonal damage in the brains of CTX patients.

Magnetization transfer MR imaging demonstrates degeneration of the subcortical and cortical gray matter in Huntington disease

BACKGROUND AND PURPOSE

GM is typically affected in HD since the presymptomatic stage. Our aim was to investigate with MT MR imaging the microstructural changes of the residual brain subcortical and cortical GM in carriers of the HD gene and to preliminarily assess their correlation with the clinical features.

MATERIALS AND METHODS

Fifteen HD gene carriers with a range of clinical severity and 15 age- and sex-matched healthy controls underwent MT MR imaging on a 1.5T scanner. The MT ratio was measured automatically in several subcortical and cortical GM regions (striatal nuclei; thalami; and the neocortex of the frontal, temporal, parietal, and occipital lobes) by using FLS tools.

RESULTS

The MT ratio was significantly (P < .05 with Bonferroni correction for multiple comparison) decreased in all subcortical structures except the putamen and decreased diffusely in the cerebral cortex of HD carriers compared with controls. Close correlation was observed between the subcortical and cortical regional MT ratios and several clinical variables, including disease duration, motor disability, and scores in timed neuropsychological tests.

CONCLUSIONS

MT imaging demonstrates degeneration of the subcortical and cortical GM in HD carriers and might serve, along with volumetric assessment, as a surrogate marker in future clinical trials of HD.

The present and the future of neuroimaging in amyotrophic lateral sclerosis

In patients with ALS, conventional MR imaging is frequently noninformative, and its use has been restricted to excluding other conditions that can mimic ALS. Conversely, the extensive application of modern MR imaging-based techniques to the study of ALS has undoubtedly improved our understanding of disease pathophysiology and is likely to have a role in the identification of potential biomarkers of disease progression. This review summarizes how new MR imaging technology is changing dramatically our understanding of the factors associated with ALS evolution and highlights the reasons why it should be used more extensively in studies of disease progression, including clinical trials.

Bimonthly assessment of magnetization transfer magnetic resonance imaging parameters in multiple sclerosis: a 14-month, multicentre, follow-up study

This study was performed to assess the temporal evolution of damage within lesions and the normal-appearing white matter, measured using frequent magnetization transfer (MT) MRI, in relapsing-remitting multiple sclerosis (RRMS). The relationship of MT ratio (MTR) changes with measures of lesion burden, and the sample sizes needed to demonstrate a treatment effect on MTR metrics in placebo-controlled MS trials were also investigated. Bimonthly brain conventional and MT MRI scans were acquired from 42 patients with RRMS enrolled in the placebo arm of a 14-month, double-blind trial. Longitudinal MRI changes were evaluated using a random effect linear model accounting for repeated measures, and adjusted for centre effects. The Expanded Disability Status Scale (EDSS) score remained stable over the study period. A weak, but not statistically significant, decrease over time was detected for normal-appearing brain tissue (NABT) average MTR (-0.02% per visit; p = 0.14), and MTR peak height (-0.15 per visit; p = 0.17), while average lesion MTR showed a significant decrease over the study period (-0.07% per visit; p = 0.03). At each visit, all MTR variables were significantly correlated with T2 lesion volume (LV) (average coefficients of correlation ranging from -0.54 to -0.28, and p-values from <0.001 to 0.02). At each visit, NABT average MTR was also significantly correlated with T1-hypointense LV (average coefficient of correlation = -0.57, p < 0.001). The estimation of the sample sizes required to demonstrate a reduction of average lesion MTR (the only parameter with a significant decrease over the follow-up) ranged from 101 to 154 patients to detect a treatment effect of 50% in a 1-year trial with a power of 90%. The steady correlation observed between conventional and MT MRI measures over time supports the hypothesis of axonal degeneration of fibres passing through focal lesions as one of the factors contributing to the overall MS burden.

Structural and metabolic brain abnormalities in preclinical cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy

OBJECTIVE

To assess, by using quantitative MRI metrics, structural and metabolic brain abnormalities in subjects with preclinical cerebral autosomal dominant arteriopathy with subcortical infarcts and leucoencephalopathy (CADASIL).

BACKGROUND

Brain MRI abnormalities have been occasionally reported in preclinical CADASIL subjects. However, very little is known as to when the brain tissue damage starts to accumulate, what brain regions are primarily involved and whether the brain damage is significant in subjects who have no overt clinical manifestations of the disease.

METHODS

Twelve subjects (mean age 40 years; range 26-55 years; males/females 6/6) with genetically proven CADASIL and no clinical signs of the disease underwent conventional MRI and proton MR spectroscopic imaging ((1)H-MRSI) to measure white matter (WM) lesion volume (LV), global and regional cerebral volumes, and WM levels of N-acetylaspartate (NAA) normalised to creatine (Cr). MR values were compared with those of 13 age- and sex-matched healthy controls.

RESULTS

All preclinical CADASIL showed WM lesions (range 0.2 to 26 cm(3)). They were mostly distributed in the frontal and parietal regions, with the highest probability in the corona radiata. On (1)H-MRSI examination, NAA/Cr values were lower in preclinical CADASIL than in HC, particularly in the corona radiata (p<0.01). Normalised brain and cortical volumes were also lower in preclinical CADASIL than in HC (p<0.01), particularly in the frontal cortex.

CONCLUSIONS

The pathological process occurring in CADASIL leads to damage of WM and neocortex much before the evidence of clinical symptoms. At this preclinical stage, this seems to take place prevalently in the frontal brain region.

The results of two multicenter, open-label studies assessing efficacy, tolerability and safety of protiramer, a high molecular weight synthetic copolymeric mixture, in patients with relapsing–remitting multiple sclerosis

Objective

Two pilot studies were conducted to evaluate safety, tolerability, and efficacy of two doses of Protiramer (TV-5010) in patients with relapsing–remitting multiple sclerosis.

Background

Both glatiramer acetate and TV-5010 are synthetic copolymers comprised the same four amino acids in a defined molar ratio. TV-5010 has higher average molecular weight than Glatiramer acetate and might be hypothesized that glatiramoids with higher molecular weight might be more immunoreactive than lower molecular weight peptides, thus increasing therapeutic potential and allowing for less frequent dosing.

Methods

In the two separate studies, after a 10 week pretreatment period, TV-5010 was given subcutaneously once weekly at 15 mg and 30 mg for 36 weeks. The primary end point was a reduction in the number of magnetic resonance imaging active lesions (i.e., T1-weigthed gadolinium-enhancing and new T2-weighted lesions) between the pretreatment period and the end of study.

Results

Both TV-5010 doses were generally well tolerated. The treatment with TV-5010 at a dose of 15 mg/wk did not show any significant effect. In contrast, in patients treated with at a dose of 30 mg/wk, a significant reduction in the mean number of gadolinium-enhancing (−58.8%; P = 0.0013) and new T2-W (−50%; P = 0.0002) lesions was observed. However, a large decrease in the mean number of both gadolinium-enhancing (−55%) and new T2-W (−40%) lesions during the pretreatment period made difficult the interpretation of the efficacy assessments.

Conclusions

Further studies are needed to confirm these preliminary data on safety and efficacy of TV-5010 at a weekly dose of 30 mg.

Increased QT variability in cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy

BACKGROUND AND PURPOSE

Although sudden death (SD) accounts for numerous cases of premature mortality in patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), the risk factors responsible for this dramatic event remain unclear. We sought possible differences in the QT variability index (QTVI) -- a well-known index of temporal dispersion in myocardial repolarization strongly associated with the risk of SD -- between a group of patients with CADASIL and healthy controls.

METHODS

A total of 13 patients with CADASIL and 13 healthy volunteers underwent a 5-min electrocardiogram recording to calculate the QTVI. All the patients also underwent a clinical assessment, including functional status by Rankin score, and a magnetic resonance imaging (MRI) brain scan for quantitative analysis of T2-weighted (T2-W) and T1-weighted (T1-W) lesion volume (LV).

RESULTS

Short-term QT-interval analysis showed significantly higher QTVI (P = 0.029) in patients than in controls. In patients, notwithstanding the limitations of the small sample size, QTVI also well correlated with T1-W LV (r = 0.747, P = 0.003) and T2-W LV (r = 0.731, P = 0.005).

CONCLUSION

Because patients with CADASIL have increased temporal cardiac repolarization variability as assessed by QTVI, this mechanism could underlie these patients' risk of SD. Whether this easily assessed, non-invasive marker could be used to stratify the risk of malignant ventricular arrhythmias in patients with CADASIL and, possibly, to guide their therapeutic management warrants confirmation from larger prospective studies.

Relating functional changes during hand movement to clinical parameters in patients with multiple sclerosis in a multi-centre fMRI study

We performed a prospective multi-centre study using functional magnetic resonance imaging (fMRI) to better characterize the relationships between clinical expression and brain function in patients with multiple sclerosis (MS) at eight European sites (56 MS patients and 60 age-matched, healthy controls). Patients showed greater task-related activation bilaterally in brain regions including the pre- and post-central, inferior and superior frontal, cingulate and superior temporal gyri and insula (P < 0.05, all statistics corrected for multiple comparisons). Both patients and healthy controls showed greater brain activation with increasing age in the ipsilateral pre-central and inferior frontal gyri (P < 0.05). Patients, but not controls, showed greater brain activation in the anterior cingulate gyrus and the bilateral ventral striatum (P < 0.05) with less hand dexterity. An interaction between functional activation changes in MS and age was found. This large fMRI study over a broadly selected MS patient population confirms that movement for patients demands significantly greater cognitive 'resource allocation' and suggests age-related differences in brain responses to the disease. These observations add to evidence that brain functional responses (including potentially adaptive brain plasticity) contribute to modulation of clinical expression of MS pathology and demonstrate the feasibility of a multi-site functional MRI study of MS.

Guidelines for using proton MR spectroscopy in multicenter clinical MS studies

Proton MR spectroscopy (MRS) allows noninvasive characterization of chemical-pathologic changes in the brain. In patients with multiple sclerosis (MS), proton MRS reveals chemical pathology in focal inflammatory lesions as well as in regions of the brain that are not associated with structural abnormalities on conventional MRI. In MS studies, it has been particularly useful as a method for the assessment of neurodegeneration based on decreases in the levels of the neuro-axonal marker compound, N-acetylaspartate. Also, MRS has provided evidence of chemical pathology and repair involving non-neuronal brain cells based on changes in metabolites, including choline, myo-inositol, glutamate, and GABA. Despite its greater pathologic specificity for axonal integrity compared to conventional MRI, MRS has been used only infrequently in clinical trials. This prompted us to review current MRS clinical applications in MS, discuss the potential and limitations of the technique, and suggest recommendations for the application of MRS to clinical trials.

Prominent brain axonal damage and functional reorganization in "pure" adrenomyeloneuropathy

BACKGROUND

Cerebral involvement is usually absent in pure adrenomyeloneuropathy (AMN). Recently, nonconventional MR studies have reported brain abnormalities in patients with pure AMN, providing evidence that occult cerebral involvement may occur in this disease. It remains unclear, however, whether these brain abnormalities reflect centripetal extension of spinal cord long-tract axonopathy or can be the expression of a pathologic process largely involving the brain.

METHODS

Conventional MRI and proton MR spectroscopic imaging (1H-MRSI) data of four patients with pure AMN were compared to those of four men with spinal cord injury (SCI) and 10 age-matched healthy men (HM). Resonance intensity areas of N-acetylaspartate (NAA) and choline were calculated as ratios to creatine (Cr) in voxels located in white matter (WM) regions. Functional MRI (fMRI) data during simple motor task were obtained in a separate session in three patients with AMN and three age-matched HM.

RESULTS

Conventional MRI examinations were normal in all patients. On 1H-MRSI, NAA/Cr values were lower in all WM regions of patients with AMN than in those of patients with SCI (p < 0.05) and HM (p < 0.01). In contrast, patients with SCI showed NAA/Cr values lower than HM only in the periventricular WM (p = 0.04). At fMRI, patients with AMN showed a more pronounced activation than HM in all movement-associated cortical regions contralateral to the hand moved and an exclusive voxel activation of the primary motor, somatosensory, and posterior parietal cortices ipsilateral to the hand moved.

CONCLUSIONS

CNS damage in pure adrenomyeloneuropathy is not confined exclusively to spinal cord and seems to primarily involve the brain.

Changes in white matter microstructure during adolescence

Postmortem histological studies have demonstrated that myelination in human brain white matter (WM) continues throughout adolescence and well into adulthood. We used in vivo diffusion-weighted magnetic resonance imaging to test for age-related WM changes in 42 adolescents and 20 young adults. Tract-Based Spatial Statistics (TBSS) analysis of the adolescent data identified widespread age-related increases in fractional anisotropy (FA) that were most significant in clusters including the body of the corpus callosum and right superior corona radiata. These changes were driven by changes in perpendicular, rather than parallel, diffusivity. These WM clusters were used as seeds for probabilistic tractography, allowing us to identify the regions as belonging to callosal, corticospinal, and prefrontal tracts. We also performed voxel-based morphometry-style analysis of conventional T1-weighted images to test for age-related changes in grey matter (GM). We identified a cluster including right middle frontal and precentral gyri that showed an age-related decrease in GM density through adolescence and connected with the tracts showing age-related WM FA increases. The GM density decrease was highly significantly correlated with the WM FA increase in the connected cluster. Age-related changes in FA were much less prominent in the young adult group, but we did find a significant age-related increase in FA in the right superior longitudinal fascicle, suggesting that structural development of this pathway continues into adulthood. Our results suggest that significant microstructural changes in WM continue throughout adolescence and are associated with corresponding age-related changes in cortical GM regions.