Specific Quantitative Measures Research Articles

What is a Feminist Quantitative Method? Opportunities for Feminist Econometrics

Though feminist economics encourages methodological plurality, quantitative methods and econometrics have overtaken the discipline in recent years. Many feminist economists have demonstrated reasons to be concerned about the increasing foothold of quantitative methods, and others have provided thoughtful criticisms of specific quantitative measurements. However, few have made distinctions between mainstream econometrics and feminist econometrics, and a succinct set of resources for those trying to do feminist quantitative research is difficult to find. Drawing upon insights from feminist economics, queer methods, and intersectional approaches, this article sets forth practical guidelines for feminists using econometric methods. Namely, it considers issues of data cleaning, replicability, survey weighting, comparison groups, non-binary measures of gender, intersectionality, causality claims, identification problems, atheoretical index composition, and measuring “difference.” It raises questions for contemporary feminist economists to consider as we grapple with the methodological identity of our field. HIGHLIGHTS Gender diagnostic estimation can be used to endogenously measure gender. Separate model approaches and CARTs are useful in intersectional work. Econometric models can be structured so they are “studying up.” Oaxaca–Blinder and PCA methods raise some feminist concerns. Cohen’s D and the Index of Similarity can be used to test gender differences.

Development of an Comprehensive Budget Management and Performance Evaluation System

The rapid advancement of socio-economic conditions and technology offers enterprises opportunities to enhance their capabilities. As they expand operations, improving management precision becomes essential. Budgeting, a crucial accounting tool for implementing corporate strategy, quantifies action plans and translates strategic planning into specific quantitative measures. Budget management involves forecasting, planning, evaluating, and providing feedback on future business activities and financial outcomes, guiding operational optimization and driving the achievement of strategic goals. Comprehensive implementation of budget management is highly significant for enterprises. This paper explores the characteristics and implementation details of comprehensive budget management, assesses the achievements and shortcomings of Company A in its practice, and analyzes its budget performance evaluation methods, particularly the deficiencies in indicator design. Using the balanced scorecard theory and methods, this study designs a budget performance evaluation indicator system tailored to Company A’s context. This system, based on the company’s strategy and objectives, employs budget performance evaluation as a means to achieve overall strategic goals through business improvement and employee motivation.

Unveiling Syndesmotic Malreduction: A Proof-of-Concept towards Portable Ultrasound Detection.

To evaluate the utility and diagnostic performance of portable handheld ultrasound for evaluating fibular rotation at the distal tibiofibular articulation after syndesmotic disruption. Four above-the-knee cadaveric specimens were included. Syndesmotic disruption was precipitated by transecting the Anterior Inferior Tibiofibular Ligament, Interosseous Ligament, and Posterior Inferior Tibiofibular Ligament. Thereafter, a proximal fibular osteotomy was performed, and three conditions were modeled at the distal syndesmosis: 1) reduced, 2) 5 degree internal rotation malreduction, and 3) 5 degree external rotation malreduction. Two blinded observers performed separate ultrasonographic examinations for each condition at the level of both the anterior and posterior distal tibiofibular articular surfaces. Syndesmotic gap penetrance, defined as the ability of the P-US to generate signal between the distal fibula and tibia at the level of the incisura, was graded positive if the sonographic waves penetrated between the distal tibiofibular joint and negative if no penetrating waves were detected. The accuracy measures of the anterior and posterior gap penetrance were evaluated individually. Our preliminary results showed that posterior gap penetrance showed good performance when detecting either internal or external rotational malreduction of the fibula with very good specificity (87.5%) and PPV (90.0%). On the other hand, the anterior gap penetrance showed limited performance when detecting either form of rotational malreduction. We introduced a novel sign, the "gap penetrance sign", best measured from the posterior ankle, which can accurately detect syndesmotic malreduction using P-US in a manner that does not require specific quantitative measurements and is readily accessible to early P-US users.

Case Study: Internal Audit's Contribution to Financial Sustainability in Self-Financing Units

The aim of this research is to demonstrate the role of internal audit activity in achieving financial sustainability in self-financing units, and to achieve the objectives of the research and test its hypotheses, we conducted a case study in municipal institutions in Nineveh Governorate. One of the most important findings of the study that the researchers reached was the weak role of internal audit in achieving financial sustainability, the lack of adoption of modern internal audit objectives, and the lack of a clear program for internal audit prepared according to sustainability. The study concluded with a number of recommendations, the most important of which are: Activating the internal audit advisory services with regard to the financial sustainability of the unit, directing its expenditures and maximizing its revenues, and the internal audit should measure the financial sustainability of the financial reporting information through specific quantitative measures.

Research on Evaluation Model of Entrepreneurship Education Based on BP Neural Network

The evaluation system of entrepreneurial practice and curriculum teaching mostly depends on the evaluation of people. Qualitative evaluation lacking specific performance and quantitative measurement is carried out through small groups. This evaluation method lacks specific quantitative and weight basis. Therefore, the evaluation results often depend on the emotional bias and cognitive bias of individuals, and the subjectivity in the evaluation process is too strong. To solve this problem, BP neural network (BP-net) is introduced into the evaluation system of entrepreneurial practice and course teaching. The model has higher adaptability and nonlinear processing ability, so the evaluation results with higher objectivity and lower deviation rate can be obtained in the evaluation. According to the evaluation characteristics of entrepreneurial practice and course teaching, a combined update design is carried out, and a new momentum term is introduced to enhance the overall operation effect of the model. Finally, the model is tested by means of performance comparison and empirical analysis. The results show that the performance score of the model reaches 4.93 points of the highest value, and the R value of the regression fitting process is stable at more than 0.90. It can conduct a comprehensive and objective analysis for different index dimensions, and split out the advantages and disadvantages of entrepreneurial practice and course teaching. This model can evaluate the quality of entrepreneurial practice and course teaching, promote the self-improvement of colleges, and create a better innovation and entrepreneurship environment for students.

RED BLOOD CELL DEFORMABILITY AND PHYSICAL ACTIVITY

Physical exertion and sport cause changes of different nature and degree (positive or negative, strong, weak, moderate) in blood and blood cells’ biomechanical and fluid properties. The aim of this minireview was to attempt to summarize the main red blood cell deformability alterations during and after physical activity classified as follows: erythrocyte geometric shape; erythrocyte membrane rheological properties; biochemical and structural properties of erythrocyte membrane lipids and proteins; hemoglobin concentration; calcium ion concentration; intracellular diffusion and osmosis; nitric oxide and erythrocyte nitric oxide synthase; erythrocyte ATP synthase; erythrocyte age and degree of erythrocyte cell maturation; body and erythrocyte temperature. It is essential to study and evaluate the individual hemorheological response profile of erythrocyte deformability during physical activity because it is strongly personal. This is one of the major erythrocyte properties determining oxygen supply to working muscles. The multiple hemorheological changes during physical activity and their interconnectedness and strong personality make their differentiation very difficult. It is reasonable to weigh their effects (with specific quantitative measurements) to simplify the analysis and increase the likelihood of obtaining valid conclusions. But there will always be the probabilistic nature of these conclusions, determined by the complex and strictly individual picture of the hemorheological effects of physical exercises and activities.

Quantitative Evaluation for Magnetoelectric Sensor Systems in Biomagnetic Diagnostics.

Dedicated research is currently being conducted on novel thin film magnetoelectric (ME) sensor concepts for medical applications. These concepts enable a contactless magnetic signal acquisition in the presence of large interference fields such as the magnetic field of the Earth and are operational at room temperature. As more and more different ME sensor concepts are accessible to medical applications, the need for comparative quality metrics significantly arises. For a medical application, both the specification of the sensor itself and the specification of the readout scheme must be considered. Therefore, from a medical user’s perspective, a system consideration is better suited to specific quantitative measures that consider the sensor readout scheme as well. The corresponding sensor system evaluation should be performed in reproducible measurement conditions (e.g., magnetically, electrically and acoustically shielded environment). Within this contribution, an ME sensor system evaluation scheme will be described and discussed. The quantitative measures will be determined exemplarily for two ME sensors: a resonant ME sensor and an electrically modulated ME sensor. In addition, an application-related signal evaluation scheme will be introduced and exemplified for cardiovascular application. The utilized prototype signal is based on a magnetocardiogram (MCG), which was recorded with a superconducting quantum-interference device. As a potential figure of merit for a quantitative signal assessment, an application specific capacity (ASC) is introduced. In conclusion, this contribution highlights metrics for the quantitative characterization of ME sensor systems and their resulting output signals in biomagnetism. Finally, different ASC values and signal-to-noise ratios (SNRs) could be clearly presented for the resonant ME sensor (SNR: dB, ASC: dB Hz) and also the electrically modulated ME sensor (SNR: dB, ASC: 23 dB Hz), showing that the electrically modulated ME sensor is better suited for a possible MCG application under ideal conditions. The presented approach is transferable to other magnetic sensors and applications.

Engineering of inorganic nanostructures with hierarchy of chiral geometries at multiple scales

Engineering of inorganic nanostructures with hierarchy of chiral geometries at multiple scales

Measurement of the tripeptides glutathione and ophthalmic acid by gas chromatography-mass spectrometry

Glutathione (GSH, γ-glutamyl-cysteinyl-glycine) is the most abundant intracellular dicarboxylic tripeptide with multiple physiological roles. GSH and its symmetric disulfide GSSG co-exist in biological samples. The GSH-to-GSSG molar ratio is high within cells and low in extracellular compartments. It is widely used as a biomarker of oxidative stress. Here, we report on a novel two-step derivatization procedure which allows for the specific quantitative measurement of GSH by gas chromatography-mass spectrometry (GC-MS) in the electron-capture negative-ion chemical ionization mode. The method is based on the derivatization of GSH first with pentafluoropropionic anhydride in ethyl acetate (30 min, 65 °C) and subsequently with 2 M HCl/CH3OH (30 min, 80 °C). Esterification in 2 M HCl/CD3OD is used for the in situ synthesis of deuterium-labelled GSH for use as internal standard. Quantification is performed by selected-ion monitoring of m/z 557 for GSH and m/z 560 for the internal standard (1 mM). Linear regression analysis between the peak area ratio of m/z 557 to m/z 560 (y) and the GSH concentration (x; range, 0–1 mM) resulted in the regression equations y = 0.02 + 0.62x (r2 = 0.976) in the absence and y = 0.02 + 0.63x (r2 = 0.997) in the presence of GSSG (range, 0–1 mM), underlying the linearity of the method for GSH and suggesting lack of interference by GSSG. γ-Glu-Cys and Cys-Gly also did not interfere. The GC-MS method demonstrated that in human hemolysate, nitrite at toxicological concentrations (range, 0–15 mM) depletes erythrocytic GSH. For the GC-MS analysis of the GSH tripeptide analogue ophthalmic acid, which lacks a Cys moiety, the derivatization order was HCl/CH3OH followed by pentafluoropropionic anhydride in ethyl acetate.

Visual Analysis of Confocal Raman Spectroscopy Data using Cascaded Transfer Function Design

Abstract2D Confocal Raman Microscopy (CRM) data consist of high dimensional per‐pixel spectral data of 1000 bands and allows for complex spectral and spatial‐spectral analysis tasks, i.e., in material discrimination, material thickness, and spatial material distributions. Currently, simple integral methods are commonly applied as visual analysis solutions to CRM data which exhibit restricted discrimination power in various regards.In this paper we present a novel approach for the visual analysis of 2D multispectral CRM data using multi‐variate visualization techniques. Due to the large amount of data and the demand of an explorative approach without a‐priori restriction, our system allows for arbitrary interactive (de)selection of varaibles w/o limitation and an unrestricted online definition/construction of new, combined properties. Our approach integrates CRM specific quantitative measures and handles material‐related features for mixed materials in a quantitative manner. Technically, we realize the online definition/construction of new, combined properties as semi‐automatic, cascaded, 1D and 2D multidimensional transfer functions (MD‐TFs). By interactively incorporating new (raw or derived) properties, the dimensionality of the MD‐TF space grows during the exploration procedure and is virtually unlimited. The final visualization is achieved by an enhanced color mixing step which improves saturation and contrast.

Modern problems of evaluation of the family policy effectiveness in the Russian Federation

The article is devoted to the multifaceted and complex problems, associated with comprehensive evaluation of the effectiveness of the state family policy. A significant stage in the development of state family policy is the adoption of the concept of state family policy in 2014. Evaluation of measures’ effectiveness in the field of family policy is the subject of many publications. However, most authors pay their attention to the individual events. It appears that the effectiveness of implementation of strategic documents is defined by the detailed development of the documents, objective approach to formation of system of target indicators. The aim of the article is the analysis of the structure of the Concept of family policy, adopted in 2014, and implementation plan of its first stage. It allows identifying whether the ineffectiveness of family policy is determined by the logic strategic documents in the field of family policy. The possibilities for monitoring the effectiveness of the action plan and the first results of the implementation of the Concept, consistency of the logic in these documents are considered. Materials and methods . The conclusions of the article are based on the analysis of quantitative and qualitative indicators of family policy. The data of statistical monitoring of family policies based on official statistical reporting and representative sample surveys of ROSSTAT, and the experience of monitoring the National strategy of actions in interests of children served as the information base of the study. Results. Currently, the performance evaluation is conducted formally; complexity evaluation for the implementation of the Concept of family policy is largely related to the logic of formation of the Concept and its expected results, the disadvantages of the formation of plans for its implementation, the lack of necessary information and special monitoring in the framework of the implementation of the Concept. In the framework of the Concept in accordance with the objectives, nine areas are highlighted, for which a list of indicators of the results has defined. The proposed indicators were not assigned to specific sections of the Concept. A number of them do not have specific quantitative measurements, which poses a substantial problem associated with the inability to conduct an objective assessment of the effectiveness of specific measures. The analysis of the logic of the Concept and implementation plan of its first stage showed that in many respects goals, objectives, indicators and financial support do not balance them. Conclusions . The problem of the ineffectiveness of large-scale conceptual and strategic documents is often linked with the logic of the document, a formal approach to the formation of a system of indicators. A number of measures, provided in the Concept, are not reflected in the implementation plan. The analysis allowed formulating proposals for clarifying the mechanism of implementation and evaluation of the effectiveness of the Concept. The most important of the proposals are the definition of the desired level of performance, projecting performance indicators of family policies in view of conflicting demographic and socio-economic dynamics; the need to develop the integrated statistical indicator of the effectiveness of family policy, covering activities in all areas.

Comment on “A Prospective Study of the Use and Effects of Screening Mammography in Women Aged 70 and Older”

The article by Vacek and Skelly focuses on the study of older women and whether breast cancer screening is necessary or beneficial.1 Being a young woman and having numerous female relatives, the topic of mammogram use and breast cancer awareness is of importance to me. There has been a great deal of debate in the medical community and among health insurance companies about how often and to what age screening should occur and how frequent screening should be. Some doctors recommend mammograms begin at the age of 40, but if there is history of breast cancer in the family, they may recommend screenings at an earlier age. Other doctors recommend that women have their first mammogram at age 50. Because there are conflicting views, there needs to be more research on this topic so that women and healthcare providers can make more evidence-based decisions. Before reading this article, I had assumed, like many others, that mammogram screening really was not necessary once a woman reached the age of 75. This study has opened my eyes and caused me to reflect on my thinking. If a woman at the age of 76 is screened and determined to have breast cancer, she is likely to live longer than if she had not had the screening. Also, life expectancy today is much higher than it was, so people in their 70s could live into their 90s if they undergo screenings and treatments. This is so relevant to current health care because women need to know that getting screened for mammograms is important throughout their whole lives no matter what age they are. I have strong feelings about breast cancer screening, which will affect decisions I make with my healthcare provider. Evidence-based practice is based on the use of quantitative studies. This study used evidence-based practice but for a narrow population of women. All the research that was conducted and the conclusions that were drawn were relevant to white women aged 70–85 who did not previously have any type of breast cancer. More than 75% of the women who participated in the study were aged 70–79. When the study was conducted, specific quantitative measures were used and taken into consideration when drawing conclusions. Vacek and Skelly's article showed that older women tend not to continue having breast cancer screening mammograms done. According to Pegg,2 women should continue to have screenings throughout their life, even when they are in their late 70s and 80s. In the 1940s, only one in 20 women had a risk of developing breast cancer, yet today the risk is greater than one in eight women. “There will be almost 233,000 new cases of breast cancer and roughly 40,000 deaths from the disease” in 2014.3 Women who have frequent breast-screening mammograms performed will be less likely to die from cancer. The American Cancer Society and other-health related groups are making efforts to educate women about the importance of breast examinations and screening, but more needs to be done. More studies need to be conducted to determine exactly when women should be screened for breast cancer. There is a debate among healthcare providers. Some experts say women should begin annual screening at the age of 40, whereas others believe screening should begin at the age of 50. The decision ultimately comes down to the woman and her doctor. Women could make more-informed decisions if more-specific conclusive research had been done.3 Conflict of Interest: The editor in chief has reviewed the conflict of interest checklist provided by the author and has determined that the author has no financial or any other kind of personal conflicts with this paper. Author Contributions: SS is the sole author of this paper. Sponsor's Role: None.

Role of the Quantitative Imaging Biomarker Alliance in Optimizing CT for the Evaluation of Lung Cancer Screen–Detected Nodules

The Quantitative Imaging Biomarker Alliance (QIBA) is a multidisciplinary consortium sponsored by the RSNA to define processes that enable the implementation and advancement of quantitative imaging methods described in a QIBA profile document that outlines the process to reliably and accurately measure imaging features. A QIBA profile includes factors such as technical (product-specific) standards, user activities, and relationship to a clinically meaningful metric, such as with nodule measurement in the course of CT screening for lung cancer. In this report, the authors describe how the QIBA approach is being applied to the measurement of small pulmonary nodules such as those found during low-dose CT-based lung cancer screening. All sources of variance with imaging measurement were defined for this process. Through a process of experimentation, literature review, and assembly of expert opinion, the strongest evidence was used to define how to best implement each step in the imaging acquisition and evaluation process. This systematic approach to implementing a quantitative imaging biomarker with standardized specifications for image acquisition and postprocessing for a specific quantitative measurement of a pulmonary nodule results in consistent performance characteristics of the measurement (eg, bias and variance). Implementation of the QIBA small nodule profile may allow more efficient and effective clinical management of the diagnostic workup of individuals found to have suspicious pulmonary nodules in the course of lung cancer screening evaluation.

Progress in Treatment Development for Neuropsychiatric Symptoms in Alzheimer's Disease: Focus on Agitation and Aggression. A Report from the EU/US/CTAD Task Force.

The management of neuropsychiatric symptoms (NPS) such as agitation and aggression is a major priority in caring for people with Alzheimer's disease (AD). Agitation and aggression (A/A) are among the most disruptive symptoms, and given their impact, they are increasingly an important target for development of effective treatments. Considerable progress has been made in the last years with a growing number of randomized controlled trials (RCTs) of drugs for NPS. The limited benefits reported in some RCTs may be accounted for by the absence of a biological link of the tested molecule to NPS and also by key methodological issues. In recent RCTs of A/A, a great heterogeneity design was found. Designing trials for dementia populations with NPS presents many challenges, including identification of appropriate participants for such trials, engagement and compliance of patients and caregivers in the trials and the choice of optimal outcome measures to demonstrate treatment effectiveness. The EU/US -CTAD Task Force, an international collaboration of investigators from academia, industry, non-profit foundations, and regulatory agencies met in Philadelphia on November 19, 2014 to address some of these challenges. Despite potential heterogeneity in clinical manifestations and neurobiology, agitation and aggression seems to be accepted as an entity for drug development. The field appears to be reaching a consensus in using both agitation and aggression (or other NPS)-specific quantitative measures plus a global rating of change for agitation outcomes based on clinician judgment as the main outcomes.

The role of the orbitofrontal cortex in cognition and behavior.

The orbitofrontal cortex (OFC) plays a crucial role in behavior and is a common site for damage due to different types of injuries, e.g., closed head injuries, cerebrovascular accidents, tumors, neurosurgical interventions. Despite the (severe) behavioral changes following OFC lesions, persons with damage to the OFC appear to be cognitively intact, i.e., at least when assessed by means of standard neuropsychological tests. Meanwhile, neuropsychological tests addressing reversal learning, gambling, and social cognition show a decline in these patients. The goal of the present review is to link the performance of these latter neuropsychological tests to behavior. The results suggest that in patients with orbitofrontal lesions, reversal learning is more associated with behavioral disinhibition and that impairment in recognition of expressed emotion is more associated with social inappropriate behavior. The faux pas test (theory of mind) appears not to be sensitive to orbitofrontal lesions. Future studies should involve a larger numbers of patients with well-defined locations in the OFC and should integrate specific neuropsychological tests and quantitative behavioral measures to better understand the contribution of the OFC to cognition and behavior.

A novel high-sensitivity electrochemiluminescence (ECL) sandwich immunoassay for the specific quantitative measurement of plasma glucagon

ObjectivesTo develop a novel, dual-monoclonal sandwich immunoassay with superior sensitivity that provides a rapid and convenient method for measuring glucagon. Glucagon is a 29-amino acid polypeptide hormone produced in the pancreas by the α-cells of the islets of Langerhans. Working in concert with insulin, glucagon is involved in regulating circulating glucose concentrations. Design and methodsThe immunoassay utilizes Meso Scale Discovery (MSD) electrochemiluminescence (ECL) technology and two affinity-optimized monoclonal antibodies. A series of experiments was performed to determine the linear range of the assay and to evaluate sensitivity, accuracy, recovery, precision, and linearity. ResultsThe sandwich assay was specific for glucagon and did not recognize the closely related peptide oxyntomodulin or other incretin peptides. The assay demonstrated excellent recovery, precision, and linearity, and a broad dynamic range of 0.14pmol/L to 1950pmol/L. In addition, assay results were highly correlated with those obtained using a previously described competitive RIA employing polyclonal antiserum. ConclusionThe use of affinity-optimized monoclonal antibodies in a sandwich immunoassay format provides a robust, sensitive, and convenient method for measuring concentrations of glucagon that is highly sensitive and specific. This immunoassay should help to improve our understanding of the role of glucagon in the regulation of glucose metabolism.

Patterns of occupant interaction with window blinds: A literature review

There is no comprehensive consensus about the way people operate blinds or the motivating factors that influence their decisions. However, there is a substantial body of research, encompassing data from more than 50 buildings worldwide, that offers guidance. Patterns of blind use can affect the energy consumption of buildings substantially and therefore energy and daylighting simulations that do not account properly for these blind use patterns will have greater error. An outline for a new more nuanced model for simulation-based blind control is offered. Specifically, this paper reviews the energy implications of blind use, blind occlusion and rate of change from field studies, specific quantitative measures influencing user blind control, investigations into user acceptance of automated blind control, and finally conclusions and knowledge gaps are summarized and suggested next steps for research are provided. Addressing these gaps is critical for the continued progress of the energy efficiency movement.

Alzheimer's disease: relationship between cognitive aspects and power and coherence EEG measures

To evaluate the relationship between specific cognitive aspects and quantitative EEG measures, in patients with mild or moderate Alzheimer's disease (AD). Thirty-eight AD patients and 31 controls were assessed by CERAD neuropsychological battery (Consortium to Establish a Registry for AD) and the electroencephalogram (EEG). The absolute power and coherences EEG measures were calculated at rest. The correlations between the cognitive variables and the EEG were evaluated. In the AD group there were significant correlations between different coherence EEG measures and Mini-Mental State Examination, verbal fluency, modified Boston naming, word list memory with repetition, word list recall and recognition, and constructional praxis (p<0.01). These correlations were all negative for the delta and theta bands and positive for alpha and beta. There were no correlations between cognitive aspects and absolute EEG power. The coherence EEG measures reflect different forms in the relationship between regions related to various cognitive dysfunctions.

Linking white matter tracts to associated cortical grey matter: A tract extension methodology

Quantitative diffusion analysis of white matter (WM) tracts has been utilised in many diseases for determining damage to, and changes in, WM tracts throughout the brain. However, there are limited studies investigating associations between quantitative measures in WM tracts and anatomically linked grey matter (GM), due to the difficulty in determining GM regions connected with a given WM tract. This work describes a straightforward method for extending a WM tract through GM based on geometry. The tract is extended by following a straight line from each point on the tract boundary to the outer boundary of the cortex. A comparison between a multiplanar 2D approach and a 3D method was made. This study also tested an analysis pipeline from tracking WM tracts to quantifying magnetisation transfer ratios (MTR) in the associated cortical GM, and assessed the applicability of the method to healthy control subjects. Tract and associated cortical volumes and MTR values for the cortico-spinal tracts, genu and body of the corpus callosum were extracted; the between-subjects standard deviation was calculated. It was found that a multiplanar 2D approach produced a more anatomically plausible volume of GM than a 3D approach, at the expense of possible overestimation of the GM volume. The between-subjects standard deviation of the tract specific quantitative measurements (from both the WM and GM masks) ranged between 1.2 and 7.3% for the MTR measures, and between 10 and 45% for the absolute volume measures. The results show that the method can be used to produce anatomically plausible extensions of the WM tracts through the GM, and regions defined in this way yield reliable estimates of the MTR from the regions.

Multimodal MRI in Neurodegenerative Disorders

In the last twenty years, advanced magnetic resonance imaging (MRI) techniques have provided fundamental knowledge about neurodegenerative processes underlying several neurological and psychiatric diseases. The native approach in this field of study was the investigation of a single MRI parameter at a time: (a) blood oxygenation-level-dependent (BOLD) images, (b) anatomical 3D T1-weighted images, (c) diffusion-weighted imaging (DWI)/diffusion tensor imaging (DTI), and (d) quantitative relaxometry. (a) The common observation in functional MRI studies is that increasing in the BOLD MRI signal represents increasing of neural activity. Such a neurophysiological “activation” results from elevated oxygen saturation levels (and reduced paramagnetic deoxyhemoglobin contents) of capillary and venous blood. These positive signal changes are considered the basis for the functional organization of the brain. (b) The T1-weighted sequence allows the employment of several neuroanatomical techniques able to describe and quantify macrostructural changes by using probabilistic (voxel-based morphometry analysis) or quantitative research tools (manual/automatic region-of-interest volumetry, cortical thickness measurements). (c) DWI and DTI provide specific quantitative measurement of micro-structural changes within white and gray matter compartments. In particular DTI provides quantitative parameters, such as the mean diffusivity that increases with microscopic barrier disruption and extracellular fluid accumulation and the fractional anisotropy that provides information on the microstructural integrity of highly oriented microstructures (i.e., myelin). (d) Finally, another potential MRI technique is the quantification of mineral levels in the brain. MR relaxometry is a sensitive method to evaluate the brain iron content in vivo. Iron accumulation has been implicated in the pathogenesis of many neurodegenerative diseases. In the last five years, multimodal neuroimaging has became the most popular approach to study pathophysiology of diseased brain. In fact, the aim of this field of study is to quantify the single or combined weight of MRI parameters in describing neurodegenerative processes. In other words, the possibility to measure MR parameters sensitive to complementary tissue characteristics (e.g., volume atrophy, iron deposition, and microstructural damage) could have great potential for investigating pathological changes in several neurologic/psychiatric diseases. At this moment, important new findings have been reported although several issues remain open. In this special edition, we have featured some papers that address such issues. The first paper of this special edition is more forward-looking. In fact, it presents a new experimental multimodal MRI approach to better elucidate interrelated gray and white matter changes in schizophrenic patients. This new method represents a theoretical evolution of the previous and well-known voxel-based analysis of T1-weighted images that generally provides a mixed measure of neuronal “volume” or “density.” The second and third papers provide fundamental overviews of recent findings about neurodegenerative processes underlying Alzheimer's disease (AD) and mild cognitive impairments (MCIs) obtained through a multimodal neuroimaging approach. The subsequent paper addresses the specific advance in functional neuroimaging studies of AD and MCI patients. All these papers highlight the importance of multimodal neuroimaging in enhancing our ability to diagnose MCI and AD in its early stages. Finally, the last two papers present the application of advanced MRI measurements (automatic ROI volumetry, cortical thickness measurements, and T2* iron quantification) to define the presence of new biomarkers able to distinguish AD patients from normal pressure hydrocephalus and to improve the accurate diagnosis of suspect neuroferritinopathy, a neurodegenerative disorder characterized by the deposition of iron and ferritin in the brain. Antonio Cerasa Andrea Cherubini Patrice Peran