MRI Tractography of Corticospinal Tract and Arcuate Fasciculus in High-Grade Gliomas Performed by Constrained Spherical Deconvolution: Qualitative and Quantitative Analysis

BACKGROUND AND PURPOSE:MR imaging tractography is increasingly used to perform noninvasive presurgical planning for brain gliomas. Recently, constrained spherical deconvolution tractography was shown to overcome several limitations of commonly used DTI tractography. The purpose of our study was to evaluate WM tract alterations of both the corticospinal tract and arcuate fasciculus in patients with high-grade gliomas, through qualitative and quantitative analysis of probabilistic constrained spherical deconvolution tractography, to perform reliable presurgical planning.MATERIALS AND METHODS:Twenty patients with frontoparietal high-grade gliomas were recruited and evaluated by using a 3T MR imaging scanner with both morphologic and diffusion sequences (60 diffusion directions). We performed probabilistic constrained spherical deconvolution tractography and tract quantification following diffusion tensor parameters: fractional anisotropy; mean diffusivity; linear, planar, and spherical coefficients.RESULTS:In all patients, we obtained tractographic reconstructions of the medial and lateral portions of the corticospinal tract and arcuate fasciculus, both on the glioma-affected and nonaffected sides of the brain. The affected lateral corticospinal tract and the arcuate fasciculus showed decreased fractional anisotropy (z = 2.51, n = 20, P = .006; z = 2.52, n = 20, P = .006) and linear coefficient (z = 2.51, n = 20, P = .006; z = 2.52, n = 20, P = .006) along with increased spherical coefficient (z = −2.51, n = 20, P = .006; z = −2.52, n = 20, P = .006). Mean diffusivity values were increased only in the lateral corticospinal tract (z = −2.53, n = 20, P = .006).CONCLUSIONS:In this study, we demonstrated that probabilistic constrained spherical deconvolution can provide essential qualitative and quantitative information in presurgical planning, which was not otherwise achievable with DTI. These findings can have important implications for the surgical approach and postoperative outcome in patients with glioma.

Gliomas are the most common type of WM-involved invasive cerebral primary neoplasm in adults. These brain tumors represent approximately 80% of primary malignant brain tumors and almost 3% of all types of cancer, and patient prognosis is poor.In recent years, the use of noninvasive study techniques, such as cortical mapping and fMRI, has improved presurgical planning for brain neoplasms. However, these methods alone are considered inadequate to achieve the primary neurosurgical aim, obtaining the most radical tumor resection with the minimum of postoperative deficits, because they do not provide good anatomic representation of the spatial location of WM tracts affected by the tumor.¹ Tractography is the most common neuroimaging technique used to reveal WM structure by analysis of DWI signals dependent on anisotropic water diffusion.² From DWI gradient directions, it is possible to generate an anisotropic map showing WM bundles and their orientations; this information is adapted by tractographic algorithms to yield a 3D representation of WM tracts. DTI-based tractography is widely used for presurgical planning and is a powerful tool in the evaluation of major WM fiber bundles; it has also a positive impact on neurosurgical resection, disease prognosis, and preservation of brain function.³ Although widely used and histologically validated,⁴ DTI approaches have several limitations, such as partial volume effects or lack of tensor estimation in voxels characterized by low fractional anisotropy (FA) values.⁵ Recent tractographic algorithms, such as probabilistic constrained spherical deconvolution (CSD), have overcome these limitations.⁶The corticospinal tract (CST) and arcuate fasciculus (AF) are 2 of the WM pathways most commonly investigated by tractography because of their important roles in voluntary movement control and language, respectively.⁷ Probabilistic CSD improves tractographic reconstruction of the lateral portion of the CST, corresponding to the somatotopic representation of hand, face, tongue, and voluntary swallow muscles, which is not detectable by DTI-based approaches.⁸ In addition, this technique allows better evaluation of all AF components, including projections to the Geschwind area and other cortical regions, compared with other tractographic methods.⁹ The main aim of this study was to evaluate WM tract alterations of both the CST and AF in patients with frontoparietal high-grade gliomas (HGGs), through a qualitative and quantitative analysis by using probabilistic CSD tractography, to obtain reliable presurgical planning.     

Organic selenium supplementation increases PHGPx but does not improve viability in chilled boar semen

This study evaluated the effects of dietary organic selenium (Se) on viability of chilled boar semen. Twelve boars were divided into three groups: control (CON), 0.3 mg kg^?1 sodium selenite; inorganic (INO), 0.5 mg kg^?1 sodium selenite and organic (ORG), 0.5 mg kg^?1 Se yeast. The experiment was conducted within 10 weeks, and analysis was performed fortnightly, in storage semen by 72 h. No effect was observed on motility; however, straightness and linearity percentages were higher (P < 0.05) in the animals receiving CON diet compared with INO group. Percentages of cells with both plasma and acrosomal intact membranes, lipidic membrane peroxidation and mitochondrial membrane potential were similar on all treatments. Animals receiving CON diet presented higher (P < 0.05) values of ATP when compared with INO group. The PHGPx was higher (P < 0.05) in animals that received ORG in comparison with INO group. In conclusion, organic selenium supplementation increases PHGPx but does not improve chilled semen viability in 72 h.     

Combining cell and gene therapy to advance cardiac regeneration

Introduction: The characterization of multipotent endogenous cardiac stem cells (eCSCs) and the breakthroughs of somatic cell reprogramming to boost cardiomyocyte replacement have fostered the prospect of achieving functional heart repair/regeneration.

Areas covered: Allogeneic CSC therapy through its paracrine stimulation of the endogenous resident reparative/regenerative process produces functional meaningful myocardial regeneration in pre-clinical porcine myocardial infarction models and is currently tested in the first-in-man human trial. The in vivo test of somatic reprogramming and cardioregenerative non-coding RNAs revived the interest in gene therapy for myocardial regeneration. The latter, together with the advent of genome editing, has prompted most recent efforts to produce genetically-modified allogeneic CSCs that secrete cardioregenerative factors to optimize effective myocardial repair.

Expert opinion: The current war against heart failure epidemics in western countries seeks to find effective treatments to set back the failing hearts prolonging human lifespan. Off-the-shelf allogeneic-genetically-modified CSCs producing regenerative agents are a novel and evolving therapy set to be affordable, safe, effective and available at all times for myocardial regeneration to either prevent or treat heart failure.     

Exploring cognitive reserve in multiple sclerosis: New findings from a cross-sectional study

Introduction: The cognitive reserve (CR) hypothesis attempts to explain the discrepancy between brain damage and clinical manifestations in neurodegenerative diseases. Recently the concept of CR was applied to the multiple sclerosis (MS) model. Our aim is to investigate the impact of demographic and clinical variables on cognitive outcome in MS patients. Method: A total of 72 MS patients were assessed by Rao’s Brief Repeatable Battery of Neuropsychological Tests (BRB-N), Cognitive Reserve Index Questionnaire (CRIq), and high field magnetic resonance examination. We performed a multivariate linear regression analysis, including each cognitive test scores as dependent variables and CRI together with age, normalized brain volume (NBV), normalized cortical volume (NCV), expanded disability severity scale (EDSS) score, and disease duration as independent variables. Moreover, we assessed whether one of the CRI subscores (CRI–Education, CRI–WorkingActivity, CRI–LeisureTime) predicted cognitive performance more than the other. Finally, to assess the CR hypothesis in our sample, we conducted the same analyses including the interaction term CRI × NCV. Results: From the multiple regression analysis, it emerged that the CRI total score influenced sustained attention, concentration, information processing speed, and verbal learning. Among the three CRI subscores, CRI–Education and CRI–WorkingActivity had the most influence. Age and EDSS score were the other significant predictors. We did not find evidence for a moderation effect of CR on negative influence of atrophy on cognitive status. Conclusions: This study focused on the contribution of CR to predict neuropsychological outcome in MS. We used a new standardized questionnaire to provide a global index including three main source of CR: education, working activity, and leisure time activities. Our preliminary findings suggest that the CR is an important predictor of better performance on cognitive tests in MS patients. However, at this stage of the study, we are unable to confirm the CR hypothesis.     

Burden of Valvular Heart Diseases in Hispanic/Latino Individuals in the United States: The Echocardiographic Study of Latinos

ObjectiveTo explore the burden and clinical correlates of valvular heart disease in Hispanics/Latinos in the United States.Patients and MethodsA total of 1818 individuals from the population-based study of Latinos/Hispanics from 4 US metropolitan areas (Bronx, New York; Chicago, Illinois; San Diego, California; and Miami, Florida) underwent a comprehensive clinical and echocardiographic examination from October 1, 2011, through June 24, 2014. Logistic regression analysis was used to examine the associations of clinical and sociodemographic variables with valvular lesions.ResultsThe mean age was 55.2±0.2 years; 57.4% were female. The prevalence of any valvular heart disease (AVHD) was 3.1%, with no considerable differences across sex, and a higher prevalence with increasing age. The proportion of US-born vs foreign-born individuals was similar in those with vs without AVHD (P=.31). The weighted prevalence of AVHD was highest in Central Americans (8.4%) and lowest in Mexicans (1.2%). Regurgitant lesions of moderate or greater severity were present in 2.4% of the population and stenotic lesions of moderate or greater severity in 0.2%. Compared with those without AVHD, individuals with AVHD were more likely to have health insurance coverage (59.6% vs 79.2%; P=.007) but similar income (P=.06) and educational status (P=.46). Univariate regression models revealed that regurgitant lesions were associated with lower body mass index whereas stenotic lesions were associated with higher body mass index.ConclusionOur data provide the first population-based estimates of the prevalence of valvular heart disease in Hispanic/Latinos. Valvular heart disease is fairly common in the Hispanic/Latino population and may constitute an important public health problem.     

An analytical model to design circumferential clasps for laser-sintered removable partial dentures

Objective

Clasps of removable partial dentures (RPDs) often suffer from plastic deformation and failure by fatigue; a common complication of RPDs. A new technology for processing metal frameworks for dental prostheses based on laser-sintering, which allows for precise fabrication of clasp geometry, has been recently developed. This study sought to propose a novel method for designing circumferential clasps for laser-sintered RPDs to avoid plastic deformation or fatigue failure.