Diffusion Tensor Imaging in Amyotrophic Lateral Sclerosis: Machine Learning for Biomarker Development.

Diffusion tensor imaging (DTI) allows the in vivo imaging of pathological white matter alterations, either with unbiased voxel-wise or hypothesis-guided tract-based analysis. Alterations of diffusion metrics are indicative of the cerebral status of patients with amyotrophic lateral sclerosis (ALS) at the individual level. Using machine learning (ML) models to analyze complex and high-dimensional neuroimaging data sets, new opportunities for DTI-based biomarkers in ALS arise. This review aims to summarize how different ML models based on DTI parameters can be used for supervised diagnostic classifications and to provide individualized patient stratification with unsupervised approaches in ALS. To capture the whole spectrum of neuropathological signatures, DTI might be combined with additional modalities, such as structural T1w 3-D MRI in ML models. To further improve the power of ML in ALS and enable the application of deep learning models, standardized DTI protocols and multi-center collaborations are needed to validate multimodal DTI biomarkers. The application of ML models to multiparametric MRI/multimodal DTI-based data sets will enable a detailed assessment of neuropathological signatures in patients with ALS and the development of novel neuroimaging biomarkers that could be used in the clinical workup.

Comparison of liver stiffness measurements by a 2D-shear wave technique and transient elastography: results from a European prospective multi-centre study.

OBJECTIVES: To compare liver stiffness measurement (LSM) provided by Canon 2D-shear wave elastography (2D-SWE) and transient elastography (TE), the latter being the reference method. METHODS: Prospective study conducted in four European centres from 2015 to 2016 including patients with various chronic liver diseases who had LSMs with both 2D-SWE and TE on the same day. Median of 10 valid measurements (in kPa) was used for comparison using paired t test, Pearson correlation, intraclass correlation coefficient (ICC) and Bland-Altman plot. The ability of 2D-SWE to stratify patient according to recognised LSM-TE thresholds was assessed by ROC curve analysis. RESULTS: Six hundred forty patients were scanned, where 593 (92.7%), 572 (89.4%) and 537 (83.9%) had reliable LSMs by TE, 2D-SWE and both combined, respectively. In the latter (n = 537, 310 [57.7%] male, mean 55.3 ± 14.8 years), median LSM-TE and LSM-2D-SWE had a mean of 10.1 ± 9.4 kPa (range 2.4-75) and 9.1 ± 6.1 kPa (range 3.6-55.7) (paired t test: p < 0.001), respectively. These were significantly correlated (Pearson r = 0.932, p < 0.001, ICC 0.850 (0.825-0.872), bias 0.99 ± 4.33 kPa [95% limits of agreement - 9.48 to + 7.49] with proportional error towards higher LSM values). LSM-2D-SWE values significantly increased with TE categories (ANOVA: p < 0.001). AUROCs ranged from 0.935 ± 0.010 (95% CI 0.910-0.954) to 0.973 ± 0.009 (95% CI 0.955-0.985), resulting in correct classification of 390/537 (73%) patients. Three 2D-SWE measurements were sufficient for reliable LSMs. CONCLUSION: LSM using 2D-SWE correlates well with TE. It tends to underestimate higher stages of liver fibrosis but correctly classifies the majority of patients. It may be used in TE-derived algorithms to manage patients. KEY POINTS: • Liver stiffness measurement (LSM) by 2D-shear wave elastography (2D-SWE) and transient elastography (TE) are strongly correlated. • 2D-SWE shows proportionately lower LSM values compared to TE, particularly with the higher LSM range. • Three individual measurements by 2D-SWE are sufficient to assess LSM reliably.

Longitudinal brain atrophy distribution in advanced Parkinson's disease: What makes the difference in "cognitive status" converters?

We investigated the brain atrophy distribution pattern and rate of regional atrophy change in Parkinson's disease (PD) in association with the cognitive status to identify the morphological characteristics of conversion to mild cognitive impairment (MCI) and dementia (PDD). T1-weighted longitudinal 3T MRI data (up to four follow-up assessments) from neuropsychologically well-characterized advanced PD patients (n = 172, 8.9 years disease duration) and healthy elderly controls (n = 85) enrolled in the LANDSCAPE study were longitudinally analyzed using a linear mixed effect model and atlas-based volumetry and cortical thickness measures. At baseline, PD patients presented with cerebral atrophy and cortical thinning including striatum, temporoparietal regions, and primary/premotor cortex. The atrophy was already observed in "cognitively normal" PD patients (PD-N) and was considerably more pronounced in cognitively impaired PD patients. Linear mixed effect modeling revealed almost similar rates of atrophy change in PD and controls. The group comparison at baseline between those PD-N whose cognitive performance remained stable (n = 42) and those PD-N patients who converted to MCI/PDD ("converter" cPD-N, n = 26) indicated suggested cortical thinning in the anterior cingulate cortex in cPD-N patients which was correlated with cognitive performance. Our results suggest that cortical brain atrophy has been already expanded in advanced PD patients without overt cognitive deficits while atrophy progression in late disease did not differ from "normal" aging regardless of the cognitive status. It appears that cortical atrophy begins early and progresses already in the initial disease stages emphasizing the need for therapeutic interventions already at disease onset.

Deficits in verbal fluency in presymptomatic C9orf72 mutation gene carriers-a developmental disorder.

BACKGROUND: A mutation in C9orf72 constitute a cross-link between amyotrophic lateral sclerosis (ALS) and fronto-temporal dementia (FTD). At clinical manifestation, both patient groups may present with either cognitive impairment of predominantly behaviour or language (in FTD) or motor dysfunctions (in ALS). METHODS: In total, 36 non-symptomatic mutation carriers from ALS or FTD families were examined, including 21 subjects with C9orf72 and 15 with SOD1 mutations. Data were compared with 91 age-matched, education-matched and gender-matched healthy subjects (56 were first-degree relatives from ALS or FTD families, 35 with no known family history of ALS/FTD). MRI scanning for diffusion tensor imaging was performed to map fractional anisotropy (FA). Subjects performed an extensive neuropsychological assessment to address verbal fluency, language, executive, memory and visuospatial function. Measurements were repeated after 12 months. RESULTS: C9orf72 expansion carriers performed significantly worse in verbal fluency and non-verbal memory and presented with distinct alterations in structural white matter integrity indicated by lower FA values in inferior and orbitofrontal cortical areas compared with carriers of SOD1 mutations or healthy subjects. Loss of structural integrity was associated with decreased verbal fluency performance. White matter alterations and cognitive performance showed no changes over 12 months in all subjects. DISCUSSION: Reduced verbal fluency performance seems to be a distinct clinical feature of C9orf72 carriers before symptomatic disease onset without evidence for change over time in our cohort. The results support the emerging hypothesis of a general disorder in development in addition to neurodegeneration in C9orf72 carriers.

To what extent does smoking affect gingival bleeding response to supragingival plaque? Site-specific analyses in a population-based study.

BACKGROUND AND OBJECTIVE: The aim of this study was to investigate the influence of smoking on the site-specific association between bleeding on gingival probing and supragingival plaque and to assess whether this differs in different regions of the dentition. METHODS: Data from a representative sample of 1911 adults (20-79 years old) in Northern Norway were analyzed. Periodontal examinations consisted of full-mouth recordings of periodontal probing depth (PD), bleeding on probing (BOP), and presence of supragingival plaque. Smoking status and background characteristics were self-reported by questionnaire. The association between plaque and BOP was assessed in several three-level (subject, tooth, and site) random intercept logistic regression models adjusted for PD, smoking status, socioeconomic factors, and body mass index. In a further model, it was assessed whether the association between supragingival plaque and BOP differed in different parts of the dentition. RESULTS: For plaque-free sites, bleeding tendency was lower in smokers, the odds ratio (OR) was 0.773 with a 95% confidence interval of 0.678-0.881 as compared to non-smokers (OR: 1; ref., P < .001). The odds of BOP at plaque-covered sites in non-smokers were increased twofold (OR: 2.117; 2.059-2.177). Albeit bleeding tendency was slightly increased in plaque-covered sites in smokers, it was considerably lower as compared to plaque-covered sites in non-smokers (OR: 1.459; 1.282-1.662, P < .001). Smoking ≥ 20 pack-years further attenuated the association. In smokers, the odds of BOP were reduced in all parts of the dentition, lower and upper anterior and posterior teeth ( χ ( 4 ) 2 = 32.043, P < .001). When restricting the data to younger adults (20-34 year old), smoking had only a slight effect on the association between plaque and BOP. For plaque-free and plaque-covered sites, differences in ORs were not statistically noticeable (P = .221 and P = .235, respectively). CONCLUSIONS: Smoking considerably attenuates the site-specific association between plaque and BOP with a dose-dependent effect. The effect of smoking did not differ across tooth types.

Severity of Fontan-Associated Liver Disease Correlates with Fontan Hemodynamics.

Fontan-palliated patients are at risk for the development of Fontan-associated liver disease (FALD). In this study, we performed a detailed hemodynamic and hepatic assessment to analyze the incidence and spectrum of FALD and its association with patients' hemodynamics. From 2017 to 2019, 145 patients underwent a detailed, age-adjusted hepatic examination including laboratory analysis (FibroTest®, n = 101), liver ultrasound (n = 117) and transient elastography (FibroScan®, n = 61). The median patient age was 16.0 years [IQR 14.2], and the median duration of the Fontan circulation was 10.3 years [IQR 14.7]. Hemodynamic assessment was performed using echocardiography, cardiopulmonary exercise capacity testing and cardiac catheterization. Liver ultrasound revealed hepatic parenchymal changes in 83 patients (70.9%). Severe liver cirrhosis was detectable in 20 patients (17.1%). Median liver stiffness measured by FibroScan® was 27.7 kPa [IQR 14.5], and the median Fibrotest® score was 0.5 [IQR 0.3], corresponding to fibrosis stage ≥ 2. Liver stiffness values and Fibrotest® scores correlated significantly with Fontan duration (P1 = 0.013, P2 = 0.012). Exercise performance was significantly impaired in patients with severe liver cirrhosis (P = 0.003). Pulmonary artery pressure and end-diastolic pressure were highly elevated in cirrhotic patients (P1 = 0.008, P2 = 0.003). Multivariable risk factor analysis revealed Fontan duration to be a major risk factor for the development of FALD (P < 0.001, OR 0.77, CI 0.68-0.87). In the majority of patients, hepatic abnormalities suggestive of FALD were detectable by liver ultrasound, transient elastography and laboratory analysis. The severity of FALD correlated significantly with Fontan duration and impaired Fontan hemodynamics. A detailed hepatic assessment is indispensable for long-term surveillance of Fontan patients.

Neurofilament light chain in serum for the diagnosis of amyotrophic lateral sclerosis.

OBJECTIVE: To determine the diagnostic and prognostic performance of serum neurofilament light chain (NFL) in amyotrophic lateral sclerosis (ALS). METHODS: This single-centre, prospective, longitudinal study included the following patients: 124 patients with ALS; 50 patients without neurodegenerative diseases; 44 patients with conditions included in the differential diagnosis of ALS (disease controls); 65 patients with other neurodegenerative diseases (20 with frontotemporal dementia, 20 with Alzheimer's disease, 19 with Parkinson's disease, 6 with Creutzfeldt-Jakob disease (CJD)). Serum NFL levels were measured using the ultrasensitive single molecule array (Simoa) technology. RESULTS: Serum NFL levels were higher in ALS in comparison to all other categories except for CJD. A cut-off level of 62 pg/mL discriminated between ALS and all other conditions with 85.5% sensitivity (95% CI 78% to 91.2%) and 81.8% specificity (95% CI 74.9% to 87.4%). Among patients with ALS, serum NFL correlated positively with disease progression rate (rs=0.336, 95% CI 0.14 to 0.506, p=0.0008), and higher levels were associated with shorter survival (p=0.0054). Serum NFL did not differ among patients in different ALS pathological stages as evaluated by diffusion-tensor imaging, and in single patients NFL levels were stable over time. CONCLUSIONS: Serum NFL is increased in ALS in comparison to other conditions and can serve as diagnostic and prognostic biomarker. We established a cut-off level for the diagnosis of ALS.

Morphological MRI investigations of the hypothalamus in 232 individuals with Parkinson's disease.

BACKGROUND: The pathophysiology of the hypothalamic involvement in Parkinson's disease (PD) is not well understood. The objective of this study was the quantification of hypothalamic volumes in vivo in PD. METHODS: High-resolution T1 -weighted magnetic resonance imaging (MRI) data from 232 individuals with PD and 130 healthy non-PD individuals were used for quantification of the hypothalamic volumes. RESULTS: The hypothalamus in PD was not atrophied, as indicated by volumetric analyses in the prospectively collected subcohort (30 PD, V = 921 ± 78 mm3 vs 30 non-PD, V = 917 ± 67 mm3 ; P = 0.850) and validated in a large cohort (202 PD, V = 925 ± 88 mm3 vs 100 non-PD, V = 932 ± 114 mm3 ; P = 0.602). CONCLUSIONS: Hypothalamic involvement in PD as shown by a large body of histopathological evidence does not appear to be detectable by MRI-based volumetric quantification. © 2019 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Dietary pattern associated with selenoprotein P and MRI-derived body fat volumes, liver signal intensity, and metabolic disorders.

PURPOSE: The association of complex dietary patterns with circulating selenoprotein P (SELENOP) levels in humans is unknown. In a general population sample, we aimed to identify a dietary pattern explaining inter-individual variation in circulating SELENOP concentrations and to study this pattern in relation to prevalent diabetes, metabolic syndrome (MetS), MRI-determined total volumes of visceral (VAT) and subcutaneous (SAT) abdominal adipose tissue, and liver signal intensity/fatty liver disease. METHODS: In this cross-sectional study, serum SELENOP levels were measured in 853 individuals. In a subsample of 553 participants, whole-body MRI was performed to assess body fat distribution and liver fat. Dietary intake was assessed by a self-administered food frequency questionnaire and the dietary pattern identified using reduced-rank regression (RRR). Multivariable linear and logistic regressions were used to investigate associations between dietary pattern score and metabolic traits. RESULTS: Characterized by high intake of fruit, vegetables and antioxidant beverages, the RRR-derived dietary pattern displayed inverse associations with VAT, SAT, MetS, and prevalent diabetes in multivariable-adjusted restricted cubic splines. Each unit increase in dietary pattern score was associated with 31% higher SELENOP levels, 12% lower VAT (95% CI: - 19%; - 5%), 13% (95% CI: - 20%; - 6%) lower SAT values and 46% (95% CI: 27%; 60%) and 53% (95% CI: 22%; 72%) lower odds of having MetS or diabetes, respectively. No meaningful relations were observed between the dietary pattern and liver traits. CONCLUSIONS: Our observations propose diet-related regulation in SELENOP levels and that the identified dietary pattern is inversely related to VAT, SAT, MetS, and prevalent diabetes.

US Time-Harmonic Elastography: Detection of Liver Fibrosis in Adolescents with Extreme Obesity with Nonalcoholic Fatty Liver Disease.

Purpose To measure in vivo liver stiffness by using US time-harmonic elastography in a cohort of pediatric patients who were overweight to extremely obese with nonalcoholic fatty liver disease (NAFLD) and to evaluate the diagnostic value of time-harmonic elastography for differentiating stages of fibrosis associated with progressive disease. Materials and Methods In this prospective study, 67 consecutive adolescents (age range, 10-17 years; mean body mass index, 34.7 kg/m2; range, 21.4-50.4 kg/m2) with biopsy-proven NAFLD were enrolled. Liver stiffness was measured by using time-harmonic elastography based on externally induced continuous vibrations of 30 Hz to 60 Hz frequency and real-time B-mode-guided wave profile analysis covering tissue depths of up to 14 cm. The diagnostic accuracy of time-harmonic elastography in staging liver fibrosis was assessed with area under the receiver operating characteristic curve (AUC) analysis. Liver stiffness cutoffs for the differentiation of fibrosis stages were identified based on the highest Youden index. Results Time-harmonic elastography was feasible in all patients (0% failure rate), including 70% (n = 47) of individuals with extreme obesity (body mass index above the 99.5th percentile). AUC analysis for the detection of any fibrosis (≥ stage F1), moderate fibrosis (≥ stage F2), and advanced fibrosis (≥ stage F3) was 0.88 (95% confidence interval [CI]: 0.80, 0.96), 0.99 (95% CI: 0.98, 1.00), and 0.88 (95% CI: 0.80, 0.96), respectively. The best liver stiffness cutoffs were 1.52 m/sec for at least stage F1, 1.62 m/sec for at least stage F2, and 1.64 m/sec for at least stage F3. Conclusion US time-harmonic elastography allows accurate detection of moderate fibrosis even in pediatric patients with extreme obesity. Larger clinical trials are warranted to confirm the accuracy of US time-harmonic elastography.

Imaging the pathoanatomy of amyotrophic lateral sclerosis in vivo: targeting a propagation-based biological marker.

OBJECTIVE: Neuropathological studies in amyotrophic lateral sclerosis (ALS) have shown a dissemination in a regional sequence in four anatomically defined patterns. The aim of this retrospective study was to see whether longitudinal diffusion tensor imaging (DTI) data support the pathological findings. METHODS: The application of DTI analysis to fibre structures that are prone to be involved at each neuropathological pattern of ALS was performed in a monocentre sample of 67 patients with ALS and 31 controls that obtained at least one follow-up scan after a median of 6 months. RESULTS: At the group level, longitudinal ALS data showed significant differences for the stage-related tract systems. At the individual level, 27% of the longitudinally scanned patients with ALS showed an increase in ALS stage, while the remaining were stable or were at the highest ALS stage. Longitudinal fractional anisotropy changes in the respective tract systems correlated significantly with the slope of the revised ALS functional rating scale. INTERPRETATION: The DTI-based protocol was able to image the disease patterns of ALS in vivo cross-sectionally and longitudinally, in support of DTI as a technical marker to image ALS stages.

Low dietary protein content alleviates motor symptoms in mice with mutant dynactin/dynein-mediated neurodegeneration.

Mutations in components of the molecular motor dynein/dynactin lead to neurodegenerative diseases of the motor system or atypical parkinsonism. These mutations are associated with prominent accumulation of vesicles involved in autophagy and lysosomal pathways, and with protein inclusions. Whether alleviating these defects would affect motor symptoms remain unknown. Here, we show that a mouse model expressing low levels of disease linked-G59S mutant dynactin p150(Glued) develops motor dysfunction >8 months before loss of motor neurons or dopaminergic degeneration is observed. Abnormal accumulation of autophagosomes and protein inclusions were efficiently corrected by lowering dietary protein content, and this was associated with transcriptional upregulations of key players in autophagy. Most importantly this dietary modification partially rescued overall neurological symptoms in these mice after onset. Similar observations were made in another mouse strain carrying a point mutation in the dynein heavy chain gene. Collectively, our data suggest that stimulating the autophagy/lysosomal system through appropriate nutritional intervention has significant beneficial effects on motor symptoms of dynein/dynactin diseases even after symptom onset.

Hypothalamic atrophy is related to body mass index and age at onset in amyotrophic lateral sclerosis.

OBJECTIVE: Our objective was to study the hypothalamic volume in a cohort of patients with amyotrophic lateral sclerosis (ALS) including symptomatic and presymptomatic ALS mutation carriers. METHODS: High-resolution three-dimensional T1-weighted MRI datasets from 251 patients with sporadic ALS, 19 symptomatic and 32 presymptomatic ALS mutation carriers and 112 healthy controls (HC) were retrospectivally registered for manual delineation of the hypothalamus. The volume of the hypothalamus, in total or subdivided, was normalised to the intracranial volume and adjusted to age. Correlation analyses were performed with clinical and metabolic outcomes. Pathologically defined ALS stages were determined in vivo by diffusion tensor imaging (DTI). RESULTS: We observed a severe atrophy of the hypothalamus both in patients with sporadic ALS (-21.8%, p<0.0001) and symptomatic ALS mutation carriers (-13.4%, p<0.001). The atrophy in patients with sporadic ALS was observed in both the anterior (-27.6% p<0.0001) and the posterior parts of the hypothalamus (-17.7%, p<0.0001). Notably, this atrophy was also observed in presymptomatic ALS mutation carriers (-15.5%, p<0.001) and was unrelated to whole brain volume atrophy or disease stage as assessed using DTI or functional status. Hypothalamic volume was correlated with body mass index (BMI) in patients with sporadic ALS (p=0.0434, ρ=+0.1579), and this correlation was much stronger in patients with familial ALS (fALS) (p=0.0060, ρ=+0.6053). Anterior hypothalamic volume was correlated with age at onset, but not with survival after MRI. CONCLUSIONS: Hypothalamus is atrophied in ALS, even in premorbid stages, and correlates with BMI, especially in fALS. Decreased anterior hypothalamic volume is associated with earlier onset of disease.

Intrinsic functional connectivity alterations in progressive supranuclear palsy: Differential effects in frontal cortex, motor, and midbrain networks.

BACKGROUND: The topography of functional network changes in progressive supranuclear palsy can be mapped by intrinsic functional connectivity MRI. The objective of this study was to study functional connectivity and its clinical and behavioral correlates in dedicated networks comprising the cognition-related default mode and the motor and midbrain functional networks in patients with PSP. METHODS: Whole-brain-based "resting-state" functional MRI and high-resolution T1-weighted magnetic resonance imaging data together with neuropsychological and video-oculographic data from 34 PSP patients (22 with Richardson subtype and 12 with parkinsonian subtype) and 35 matched healthy controls were subjected to network-based functional connectivity and voxel-based morphometry analysis. RESULTS: After correction for global patterns of brain atrophy, the group comparison between PSP patients and controls revealed significantly decreased functional connectivity (P < 0.05, corrected) in the prefrontal cortex, which was significantly correlated with cognitive performance (P = 0.006). Of note, midbrain network connectivity in PSP patients showed increased connectivity with the thalamus, on the one hand, whereas, on the other hand, lower functional connectivity within the midbrain was significantly correlated with vertical gaze impairment, as quantified by video-oculography (P = 0.004). PSP Richardson subtype showed significantly increased functional motor network connectivity with the medial prefrontal gyrus. CONCLUSIONS: PSP-associated neurodegeneration was attributed to both decreased and increased functional connectivity. Decreasing functional connectivity was associated with worse behavioral performance (ie, dementia severity and gaze palsy), whereas the pattern of increased functional connectivity may be a potential adaptive mechanism. © 2017 International Parkinson and Movement Disorder Society.

Patterns of Eye Movement Impairment Correlate with Regional Brain Atrophy in Neurodegenerative Parkinsonism.

BACKGROUND: One common feature of neurodegenerative parkinsonism including Parkinson's disease (PD), multisystem atrophy (MSA), and progressive supranuclear palsy (PSP) is altered eye movement control. Characteristic regional structural atrophy patterns in MRI can be observed in PD, MSA, and PSP. OBJECTIVE: To investigate the association between eye movement disturbances and regional brain atrophy in patients with PD, MSA, and PSP. METHODS: High-resolution 3-dimensional T1-weighted MRI images and video-oculographic recordings (EyeLink®) were obtained from 39 PD, 32 PSP, and 18 MSA patients and 24 matched healthy control subjects. Automatic regional volumetric assessment was performed using atlas-based volumetry (ABV). RESULTS: The prevalence of saccadic intrusions as a measure of inhibitory control was significantly increased in PD patients compared to controls (p < 0.001) and negatively correlated with whole brain volume, cerebral brain volume, and occipital lobe volume (p = 0.0057, p = 0.0049, and p = 0.0059, respectively; all p values are false discovery rate corrected). In MSA, smooth pursuit was disturbed by characteristic "catch-up" saccades (p < 0.001) and it was significantly correlated with cerebellar volume (p = 0.004) and pontine volume (p < 0.001). The hallmark of PSP was pathologically slowed vertical peak eye velocities (p < 0.001); the lower the peak eye velocity, the more marked midbrain atrophy (p = 0.007). CONCLUSIONS: Foci of regional atrophy correlated with disease-specific eye movement alterations in all investigated parkinsonian syndromes. Oculomotor impairment in PD, predominantly the result of executive dysfunction, was linked to cerebral atrophy. Impairment in the corresponding oculomotor pathways was associated with atrophy of pontocerebellar oculomotor structures in MSA and midbrain atrophy in PSP.

A large-scale multicentre cerebral diffusion tensor imaging study in amyotrophic lateral sclerosis.

OBJECTIVE: Damage to the cerebral tissue structural connectivity associated with amyotrophic lateral sclerosis (ALS), which extends beyond the motor pathways, can be visualised by diffusion tensor imaging (DTI). The effective translation of DTI metrics as biomarker requires its application across multiple MRI scanners and patient cohorts. A multicentre study was undertaken to assess structural connectivity in ALS within a large sample size. METHODS: 442 DTI data sets from patients with ALS (N=253) and controls (N=189) were collected for this retrospective study, from eight international ALS-specialist clinic sites. Equipment and DTI protocols varied across the centres. Fractional anisotropy (FA) maps of the control participants were used to establish correction matrices to pool data, and correction algorithms were applied to the FA maps of the control and ALS patient groups. RESULTS: Analysis of data pooled from all centres, using whole-brain-based statistical analysis of FA maps, confirmed the most significant alterations in the corticospinal tracts, and captured additional significant white matter tract changes in the frontal lobe, brainstem and hippocampal regions of the ALS group that coincided with postmortem neuropathological stages. Stratification of the ALS group for disease severity (ALS functional rating scale) confirmed these findings. INTERPRETATION: This large-scale study overcomes the challenges associated with processing and analysis of multiplatform, multicentre DTI data, and effectively demonstrates the anatomical fingerprint patterns of changes in a DTI metric that reflect distinct ALS disease stages. This success paves the way for the use of DTI-based metrics as read-out in natural history, prognostic stratification and multisite disease-modifying studies in ALS.

Neurofilaments in the diagnosis of motoneuron diseases: a prospective study on 455 patients.

OBJECTIVES: Biomarkers for the diagnosis of motoneuron diseases (MND) are urgently needed to improve the diagnostic pathway, patient stratification and monitoring. The aim of this study was to validate candidate markers for MND in cerebrospinal fluid (CSF) and specify cut-offs based on large patient cohorts by especially considering patients who were seen under the initial differential diagnosis (MND mimics). METHODS: In a prospective study, we investigated CSF of 455 patients for neurofilament light chain (NfL), phosphorylated heavy chain (pNfH), tau protein (Tau) and phospho-tau protein (pTau). Analysed cohorts included patients with apparently sporadic and familial amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS) (MND, n=253), MND mimics (n=85) and neurological control groups. Cut-off values were specified, and diagnostic performance and correlation with progression were analysed. RESULTS: Nfs were significantly higher in the MND group compared to the control groups, whereas Tau and pTau did not differ. At a cut-off level of 2200 pg/mL for NfL, a 77% diagnostic sensitivity (CI 71% to 82%), 85% specificity (CI 79% to 90%) and 87% positive predictive value (PPV) (CI 81% to 91%) were achieved. For pNfH, we calculated 83% sensitivity (CI 78% to 88%), 77% specificity (CI 71% to 83%) and 82% PPV (CI 77% to 86%) at 560 pg/mL. There were no significant differences between sporadic and genetic ALS or PLS. Nf levels were elevated at early disease stage, and correlated moderately with MND progression and duration. CONCLUSIONS: Neurofilaments in CSF have a high relevance for the differential diagnosis of MNDs and should be included in the diagnostic work-up of patients. Their value as prognostic markers should be investigated further.

Retinal involvement in amyotrophic lateral sclerosis: a study with optical coherence tomography and diffusion tensor imaging.

Although motor neuron degeneration is the predominant feature in ALS, recent data point to a more widespread pathology also comprising non-motor symptoms. Retinal thinning has been reported in a variety of neurodegenerative conditions. Yet, studies of retinal involvement in ALS are sparse and results are heterogeneous. We studied retinal alterations in ALS using a systematic approach combining Optical Coherence Tomography (OCT), Diffusion Tensor Imaging (DTI) and clinical phenotyping. We hypothesized that selective changes of specific retinal layers may be a reflection of overall neurodegeneration as measured by DTI. Spectral domain OCT images were analyzed to calculate the average thickness of retinal layers in 71 ALS patients and 20 controls. In 30 patients, the region of interest (ROI) based fractional anisotrophy (FA) was measured in the corticospinal tract (CST), as this region is preferentially affected by motor neuron degeneration. Clinical data were collected for correlation analysis. Patients showed a significant thinning of the inner nuclear layer (INL; p = 0.04) and the retinal nerve fibre layer (RNFL; p = 0.004) compared to controls. We saw significant correlations between retinal thickness and FA values of the CST in patients (p = 0.005). No significant correlation between clinical parameters and retinal involvement was observed. Our study provides evidence for a retinal involvement in ALS. Interestingly, ALS patients show a reduction in FA of the CST, which is correlated to retinal thinning. We conclude that retinal involvement is in fact associated to overall neurodegeneration and may be regarded as a potential technical biomarker in ALS.

Association of food consumption with total volumes of visceral and subcutaneous abdominal adipose tissue in a Northern German population.

Excess accumulation of visceral adipose tissue (VAT) is a known risk factor for cardiometabolic diseases; further, subcutaneous abdominal adipose tissue (SAAT) and the ratio of both (VAT:SAAT ratio) have been discussed as potentially detrimental. Information about the association between diet and adipose tissue is scarce. This study aimed to identify food group intake associated with VAT and SAAT and the VAT:SAAT ratio in a Northern German population. A cross-sectional analysis was conducted in 344 men and 241 women who underwent an MRI to quantify total volumes of VAT and SAAT. Intake of fourteen food groups was assessed with a self-administered 112-item FFQ. Linear regression models adjusted for age, sex, energy intake, physical activity, intake of other food groups and mutual adjustment for VAT and SAAT were calculated to analyse the associations between standardised food group intake and VAT and SAAT, or the VAT:SAAT ratio. Intakes of potatoes (P=0·043) and cakes (P=0·003) were positively and inversely, respectively, associated with both VAT and SAAT. By contrast, intake of cereals was negatively associated with VAT (P=0·045) only, whereas intakes of eggs (P=0·006) and non-alcoholic beverages (P=0·042) were positively associated with SAAT only. The association between eggs and non-alcoholic beverages with SAAT remained significant after further consideration of VAT. Intake of non-alcoholic beverages was also inversely associated with the VAT:SAAT ratio (P=0·001). Our analysis adds to the evidence that intake of foods is independently associated with VAT or SAAT volumes.