T1w/FLAIR ratio standardization as a myelin marker in MS patients

Image calibration; Integrity; Multiple sclerosisCalibración de imagen; Integridad; Esclerosis múltipleCalibració d'imatge; Integritat; Esclerosi múltipleIntroduction Calculation of a T1w/T2w ratio was introduced as a proxy for myelin integrity in the brain of multiple sclerosis (MS) patients. Since nowadays 3D FLAIR is commonly used for lesion detection instead of T2w images, we introduce a T1w/FLAIR ratio as an alternative for the T1w/T2w ratio. Objectives Bias and intensity variation are widely present between different scanners, between subjects and within subjects over time in T1w, T2w and FLAIR images. We present a standardized method for calculating a histogram calibrated T1w/FLAIR ratio to reduce bias and intensity variation in MR sequences from different scanners and at different time-points. Material and methods 207 Relapsing Remitting MS patients were scanned on 4 different 3 T scanners with a protocol including 3D T1w, 2D T2w and 3D FLAIR images. After bias correction, T1w/FLAIR ratio maps and T1w/T2w ratio maps were calculated in 4 different ways: without calibration, with linear histogram calibration as described by Ganzetti et al. (2014), and by using 2 methods of non-linear histogram calibration. The first nonlinear calibration uses a template of extra-cerebral tissue and cerebrospinal fluid (CSF) brought from Montreal Neurological Institute (MNI) space to subject space; for the second nonlinear method we used an extra-cerebral tissue and CSF template of our own subjects. Additionally, we segmented several brain structures such as Normal Appearing White Matter (NAWM), Normal Appearing Grey Matter (NAGM), corpus callosum, thalami and MS lesions using Freesurfer and Samseg. Results The coefficient of variation of T1w/FLAIR ratio in NAWM for the no calibrated, linear, and 2 nonlinear calibration methods were respectively 24, 19.1, 9.5, 13.8. The nonlinear methods of calibration showed the best results for calculating the T1w/FLAIR ratio with a smaller dispersion of the data and a smaller overlap of T1w/FLAIR ratio in the different segmented brain structures. T1w/T2w and T1w/FLAIR ratios showed a wider range of values compared to MTR values. Conclusions Calibration of T1w/T2w and T1w/FLAIR ratio maps is imperative to account for the sources of variation described above. The nonlinear calibration methods showed the best reduction of between-subject and within-subject variability. The T1w/T2w and T1w/FLAIR ratio seem to be more sensitive to smaller changes in tissue integrity than MTR. Future work is needed to determine the exact substrate of T1w/FLAIR ratio and to obtain correlations with clinical outcome

Blood and neuroimaging biomarkers of cognitive sequelae in breast cancer patients throughout chemotherapy:A systematic review

Breast cancer treatment can induce alterations in blood-and neuroimaging-based markers. However, an overview of the predictive value of these markers for cognition is lacking for breast cancer survivors. This systematic review summarized studies of the last decade, using the PubMed database, evaluating blood markers, and the association between blood-or structural neuroimaging markers and cognition across the chemotherapy trajectory for primary breast cancer, following PRISMA guidelines. Forty-four studies were included. Differences were observed in all blood marker categories, from on-therapy until years post-chemotherapy. Associations were found between cognitive functioning and (1) blood markers (mainly inflammation-related) during, shortly-, or years post-chemotherapy and (2) white and gray matter metrics in frontal, temporal and parietal brain regions months up until years post-chemotherapy. Preliminary evidence exists for epigenetic and metabolic changes being associated with cognition, only after chemotherapy. This review demonstrated time-dependent associations between specific blood-based and structural neuroimaging markers with cognitive impairment in patients with breast cancer. Future studies are encouraged to include both neuroimaging-and blood markers (e.g. of neuronal integrity, epigenetics and metabolism) to predict long-term cognitive effects of chemotherapy

Town of Jay Annual Report Year Ending June 30, 2014

status: publishe

The impact of mindfulness on functional brain connectivity and peripheral inflammation in breast cancer survivors with cognitive complaints

Simple Summary Cognitive impairment is a common side effect of cancer treatment and impacts the quality of life of cancer survivors. As there is currently no golden standard for the treatment of cancer-related cognitive impairment (CRCI), we investigated the potential of a mindfulness-based intervention to impact the underlying mechanisms of CRCI. Breast cancer survivors with cognitive complaints (n = 117) were randomly assigned to a mindfulness, physical training, or waitlist control group. Resting state functional MRI data and serum blood samples were collected and compared before and after the intervention. We could not identify differences between the groups in resting state functional connectivity. However, the functional organization of attention-, salience- and executive functioning-related neural networks differed between both intervention groups and the waitlist control group. Additionally, physical training could alter therapy-induced immune deregulation. In conclusion, physical training had the most pronounced effects on functional network organization and biomarkers of inflammation, two mechanisms that might be involved in CRCI. Background: Cancer-related cognitive impairment (CRCI) has been linked to functional brain changes and inflammatory processes. Hence, interventions targeting these underlying mechanisms are needed. In this study, we investigated the effects of a mindfulness-based intervention on brain function and inflammatory profiles in breast cancer survivors with CRCI. Methods: Female breast cancer survivors reporting cognitive complaints (n = 117) were randomly assigned to a mindfulness-based intervention (n = 43), physical training (n = 36), or waitlist control condition (n = 38). Region-of-interest (ROI) and graph theory analyses of resting state functional MRI data were performed to study longitudinal group differences in functional connectivity and organization in the default mode, dorsal attention, salience, and frontoparietal network. Additionally, bead-based immunoassays were used to investigate the differences in inflammatory profiles on serum samples. Measures were collected before, immediately after and three months post-intervention. Results: No ROI-to-ROI functional connectivity changes were identified. Compared to no intervention, graph analysis showed a larger decrease in clustering coefficient after mindfulness and physical training. Additionally, a larger increase in global efficiency after physical training was identified. Furthermore, the physical training group showed a larger decrease in an inflammatory profile compared to no intervention (IL-12p70, IFN-& gamma;, IL-1 & beta;, and IL-8). Conclusion: Both mindfulness and physical training induced changes in the functional organization of networks related to attention, emotion processing, and executive functioning. While both interventions reduced functional segregation, only physical training increased functional integration of the neural network. In conclusion, physical training had the most pronounced effects on functional network organization and biomarkers of inflammation, two mechanisms that might be involved in CRCI

Neuroinflammation as potential precursor of leukoencephalopathy in early-stage breast cancer patients:A cross-sectional PET-MRI study

BACKGROUND: Although chemotherapy-induced leukoencephalopathy has been described in case and cohort studies, literature remains inconclusive about its prevalence and mechanisms. Therefore, we investigated the presence of leukoencephalopathy after multiagent chemotherapy in women treated for breast cancer and potential underlying neuroinflammatory processes. METHODS: In this exploratory study, 15 chemotherapy-treated and 15 age-matched chemotherapy-naïve patients with early-stage breast cancer, as well as 15 healthy controls underwent simultaneous PET-MR neuroimaging, including T1-weighted MPRAGE, T2-weighted FLAIR and dynamic PET with the 18-kDA translocator protein (TSPO) radioligand [(18)F]DPA-714. Total and regional (juxtacortical, periventricular, deep white matter and infratentorial) lesion burden were compared between the groups with one-way ANOVA. With paired t-tests, [(18)F]DPA-714 volume of distribution [V(T), including partial volume correction (PVC)] in lesioned and normal appearing white matter (NAWM) were compared within subjects, to investigate inflammation. Finally, two general linear models were used to examine the predictive values of neurofilament light-chain (NfL) serum levels on (1) total lesion burden or (2) PVC [(18)F]DPA-714 V(T) of lesions showing elevated inflammation. RESULTS: No significant differences were found in total or localized lesion burden. However, significantly higher (20–45%) TSPO uptake was observed in juxtacortical lesions (p ≤ 0.008, t ≥ 3.90) compared to NAWM in both cancer groups, but only persisted for chemotherapy-treated patients after PVC (p = 0.005, t = 4.30). NfL serum levels were not associated with total lesion volume or tracer uptake in juxtacortical lesions. CONCLUSION: This multimodal neuroimaging study suggests that neuroinflammatory processes could be involved in the development of juxtacortical, but not periventricular or deep white matter, leukoencephalopathy shortly after chemotherapy for early-stage breast cancer

Functional magnetic resonance imaging : cerebral function alterations in subthreshold and suprathreshold spinal cord stimulation

Peer reviewedPublisher PD

Engaging GPs in insulin therapy initiation : a qualitative study evaluating a support program in the Belgian context

Background: A program supporting the initiation of insulin therapy in primary care was introduced in Belgium, as part of a larger quality improvement project on diabetes care. This paper reports on a study exploring factors influencing the engagement of general practitioners (GPs) in insulin therapy initiation (research question 1) and exploring factors relevant for future program development (research question 2). Methods: We have used semi-structured interviews to answer the first research question: two focus group interviews with GPs who had at least one patient in the insulin initiation program and 20 one-to-one interviews with GPs who were not regular users of the overall support program in the region. To explore factors relevant for future program development, the data from the GPs were triangulated with data obtained from individual interviews with patients (n=10), the diabetes nurse educator (DNE) and the specialist involved in the program, and data extracted from meeting reports evaluating the insulin initiation support program. Results: We found differences between GPs engaged and those not engaged in insulin initiation in attitude, subjective norm and perceived behavioural control regarding insulin initiation. In general the support program was evaluated in a positive way by users of the program. Some aspects need further consideration: job boundaries between the DNE and GPs, job boundaries between GPs and specialists, protocol adherence and limited case load. Conclusion: The study shows that the transition of insulin initiation from secondary care to the primary care setting is a challenge. Although a support program addressing known barriers to insulin initiation was provided, a substantial number of GPs were reluctant to engage in this aspect of care. Important issues for future program development are: an interdisciplinary approach to job clarification, a dynamic approach to the integration of expertise in primary care and feedback on protocol adherence. Trial registration: ClinicalTrials.gov Identifier:NCT0082449

The effect of spaceflight and microgravity on the human brain

peer reviewedMicrogravity, confinement, isolation, and immobilization are just some of the features astronauts have to cope with during space missions. Consequently, long-duration space travel can have detrimental effects on human physiology. Although research has focused on the cardiovascular and musculoskeletal system in particular, the exact impact of spaceflight on the human central nervous system remains to be determined. Previous studies have reported psychological problems, cephalic fluid shifts, neurovestibular problems, and cognitive alterations, but there is paucity in the knowledge of the underlying neural substrates. Previous space analogue studies and preliminary spaceflight studies have shown an involvement of the cerebellum, cortical sensorimotor, and somatosensory areas and the vestibular pathways. Extending this knowledge is crucial, especially in view of long-duration interplanetary missions (e.g., Mars missions) and space tourism. In addition, the acquired insight could be relevant for vestibular patients, patients with neurodegenerative disorders, as well as the elderly population, coping with multisensory deficit syndromes, immobilization, and inactivity

A crucial role for the cortico-striato-cortical loop in the pathogenesis of stroke-related neurogenic stuttering

Neurogenic stuttering is an acquired speech disorder characterized by the occurrence of stuttering-like dysfluencies following brain damage. Because the onset of stuttering in these patients is associated with brain lesions, this condition provides a unique opportunity to study the neural processes underlying speech dysfluencies. Lesion localizations of 20 stroke subjects with neurogenic stuttering and 17 control subjects were compared using voxel-based lesion symptom mapping. The results showed nine left-hemisphere areas associated with the presen ce of neurogenic stuttering. These areas were largely overlapping with the cortico-basal ganglia-cortical network comprising the inferior frontal cortex, superior temporal cortex, intraparietal cortex, basal ganglia, and their white matter interconnections through the superior longitudinal fasciculus and internal capsule. These results indicated that stroke-induced neurogenic stuttering is not associated with neural dysfunction in one specific brain area but can occur following one or more lesion throughout the cortico-basal ganglia-cortical network. It is suggested that the onset of neurogenic stuttering in stroke subjects results from a disintegration of neural functions necessary for fluent speech. © 2012 Wiley Periodicals, Inc