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.

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.

Regional cortical thinning in multiple sclerosis and its relation with cognitive impairment: A multicenter study

Objectives:

The objectives of this paper are to compare in a multicenter setting patterns of regional cortical thickness in patients with relapsing–remitting multiple sclerosis (RRMS) and cognitive impairment (CI) and those cognitively preserved (CP), and explore the relationship between cortical thinning and cognitive performance.

Methods:

T1-weighted isotropic brain scans were collected at 3T from seven European centers in 60 RRMS patients and 65 healthy controls (HCs). Patients underwent clinical and neuropsychological examinations. Cortical thickness (CTh) measures were calculated using FreeSurfer (failing in four) and both lobar and vertex-based general linear model (GLM) analyses were compared between study groups.

Results:

Twenty (36%) MS patients were classified as CI. Mean global CTh was smaller in RRMS patients compared to HCs (left 2.43 vs. 2.53 mm, right 2.44 vs. 2.54 mm, p < 0.001). Multivariate GLM regional analysis showed significantly more temporal thinning in CI compared to CP patients. Verbal memory scores correlated to regional cortical thinning in the insula whereas visual memory scores correlated to parietal thinning.

Conclusions:

This multicenter study showed mild global cortical thinning in RRMS. The extent of thinning is less pronounced than previously reported. Only subtle regional differences between CI and CP patients were observed, some of which related to specific cognitive domains.

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.

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.

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.

Validation of the DYMUS questionnaire for the assessment of dysphagia in multiple sclerosis

Swallowing problems can complicate the course of multiple sclerosis (MS). However, no validated questionnaire for the assessment of dysphagia in MS is currently available. We previously developed a 10-item DYsphagia in Multiple Sclerosis questionnaire (DYMUS). In the present study, this questionnaire was submitted to a validation process. Thirteen Italian MS centres took part in this research in which DYMUS was administered to 1734 consecutive MS patients during routine checkups outside relapse. The questionnaire showed very good internal consistency (Cronbach's alpha = 0.914). It was then subdivided into two subscales, both of which also showed very good internal consistency: Cronbach's alpha was 0.885 for the 'dysphagia for solids' subscale and 0.864 for the 'dysphagia for liquids' subscale. The DYMUS questionnaire was found to be an easy and reliable tool for detecting dysphagia and also for the preliminary selection of patients requiring more specific instrumental analyses, and those suitable for aspiration prevention programmes.

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.

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.

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.

Leukoencephalopathy as a rare complication of hepatitis C infection

We report the case of a 64-year-old female patient with hepatitis C infection (HCV), who developed Sjögren's disease and sensory peripheral neuropathy. Clinical conditions worsened over three years with central nervous system involvement characterised by transient third cranial nerve paresis and mild selective impairment of attention and memory. Brain magnetic resonance imaging showed diffuse periventricular and lobar white matter hyperintensity. Laboratory findings included mixed cryoglobulinaemia (type II), cryocrit 1.47%, low serum levels of complement C4 and high levels of rheumatoid factor, HCV 1b genotype, high HCV mRNA levels in serum and cerebrospinal fluid. Skin biopsy showed evidence of vasculitis. After one year of plasmapheresis, immunosuppressant therapy and occasional corticosteroid treatment, neurological symptoms improved, skin biopsy changed and inflammation parameters normalised, suggesting that neurological symptoms might be related to the high levels of mixed cryoglobulins.

Peripheral neuropathy in vanishing white matter disease with a novel EIF2B5 mutation

The authors describe an infant with vanishing white matter disease with demyelinating peripheral neuropathy. Sequence analysis of EIF2B5 gene showed that the patient was a double heterozygote, with novel missense mutation CGA-->CAA in codon 269 of exon 6, resulting in the replacement of an arginine residue with glutamine.

Brain damage as detected by magnetization transfer imaging is less pronounced in benign than in early relapsing multiple sclerosis

The trend to start disease-modifying therapy early in the course of multiple sclerosis makes it important to establish whether the benign form is a real entity. In previous studies, measures of magnetization transfer (MT) ratio (MTr) have been shown to provide good estimates of the amount of tissue damage occurring in multiple sclerosis brains. Thus, with the hypothesis that if benign multiple sclerosis patients were really benign, sensitive measures of subtle tissue damage would be less pronounced in these patients than in very early relapsing-remitting (RR) multiple sclerosis patients. We carried out conventional MRI and MT imaging in 50 patients with benign multiple sclerosis [defined as having Kurtzke Expanded Disability Status Score (EDSS) <3 and disease duration >15 years] and in 50 early RR patients selected to have similar disability (EDSS <3) and short disease duration (<3 years). Data were compared with those of 32 demographically-matched normal controls. We used a fully automated procedure to measure lesional-MTr, perilesional-MTr, normal-appearing white matter (NAWM) MTr and cortical-MTr. We found that, after correction for common effects of age, lesional-MTr and perilesional-MTr of benign patients were significantly (P < 0.0001) lower than WM of normal controls, but significantly (P < 0.0001) higher than corresponding tissues of RR patients. In NAWM and cortex, MTr values of benign patients were similar to those of normal controls (P > 0.5) and significantly higher than those of the RR patients (P < 0.0001 and P < 0.01, respectively). Similar differences in MTr measures between benign and RR patients were found when patient groups were selected to have no disability (EDSS < or = 2) and, for benign multiple sclerosis, very long disease duration (>20 years) or when both groups were matched for high lesion load (T2-weighted lesion volume >10 cm3). We conclude that lesional and non-lesional MTr values can be significantly less pronounced in benign multiple sclerosis than in a cohort of RR patients at their earliest disease stages, suggesting that brain tissue damage is milder in benign multiple sclerosis than in early RR disease. This can be due to an extraordinary beneficial response to demyelination of benign patients and may represent the evidence that benign multiple sclerosis truly exists and might be differentiated from other forms of this illness.

Mitochondrial alterations in muscle biopsies of patients on statin therapy

Clinical and biopsy study of nine patients on statin therapy suffering from various myopathic syndromes is reported. Biopsy findings showed non specific myopathic signs and mitochondrial changes, such as subsarcolemmal accumulation, morphological alterations, lipid increase and Cox-negative fibers. These findings confirm that statins may cause muscle damage and impair oxidative metabolism.

Imaging neuronal and axonal degeneration in multiple sclerosis

Neuronal and axonal damage has become an important issue in multiple sclerosis. This has been emphasised by recent magnetic resonance imaging (MRI) studies that have shown evidence of axonal damage in both lesional and non-lesional white matter and in grey matter. In this respect, proton MR spectroscopy (by monitoring levels of Nacetylaspartate, a putative marker of axonal integrity) and computed measurements of cerebral volumes have been particularly illuminating. Recent studies using these MRI measures have demonstrated that cerebral neuro-axonal damage begins and contributes to disability from the earliest stages of the disease. This implies that the apparently primary role of neuronal pathology in the pathogenesis of the disease should be given due importance and argues for the early treatment of multiple sclerosis with agents directed not only against inflammation, but also towards neuronal protection.