scholarly journals Differences Between MR Brain Region Segmentation Methods: Impact on Single-Subject Analysis

2021 ◽  
Vol 4 ◽  
Author(s):  
W. Huizinga ◽  
D. H. J. Poot ◽  
E. J. Vinke ◽  
F. Wenzel ◽  
E. E. Bron ◽  
...  

For the segmentation of magnetic resonance brain images into anatomical regions, numerous fully automated methods have been proposed and compared to reference segmentations obtained manually. However, systematic differences might exist between the resulting segmentations, depending on the segmentation method and underlying brain atlas. This potentially results in sensitivity differences to disease and can further complicate the comparison of individual patients to normative data. In this study, we aim to answer two research questions: 1) to what extent are methods interchangeable, as long as the same method is being used for computing normative volume distributions and patient-specific volumes? and 2) can different methods be used for computing normative volume distributions and assessing patient-specific volumes? To answer these questions, we compared volumes of six brain regions calculated by five state-of-the-art segmentation methods: Erasmus MC (EMC), FreeSurfer (FS), geodesic information flows (GIF), multi-atlas label propagation with expectation–maximization (MALP-EM), and model-based brain segmentation (MBS). We applied the methods on 988 non-demented (ND) subjects and computed the correlation (PCC-v) and absolute agreement (ICC-v) on the volumes. For most regions, the PCC-v was good (>0.75), indicating that volume differences between methods in ND subjects are mainly due to systematic differences. The ICC-v was generally lower, especially for the smaller regions, indicating that it is essential that the same method is used to generate normative and patient data. To evaluate the impact on single-subject analysis, we also applied the methods to 42 patients with Alzheimer’s disease (AD). In the case where the normative distributions and the patient-specific volumes were calculated by the same method, the patient’s distance to the normative distribution was assessed with the z-score. We determined the diagnostic value of this z-score, which showed to be consistent across methods. The absolute agreement on the AD patients’ z-scores was high for regions of thalamus and putamen. This is encouraging as it indicates that the studied methods are interchangeable for these regions. For regions such as the hippocampus, amygdala, caudate nucleus and accumbens, and globus pallidus, not all method combinations showed a high ICC-z. Whether two methods are indeed interchangeable should be confirmed for the specific application and dataset of interest.

2020 ◽  
Vol 15 (3) ◽  
pp. 187-201 ◽  
Author(s):  
Sunil K. Dubey ◽  
Amit Alexander ◽  
Munnangi Sivaram ◽  
Mukta Agrawal ◽  
Gautam Singhvi ◽  
...  

Damaged or disabled tissue is life-threatening due to the lack of proper treatment. Many conventional transplantation methods like autograft, iso-graft and allograft are in existence for ages, but they are not sufficient to treat all types of tissue or organ damages. Stem cells, with their unique capabilities like self-renewal and differentiate into various cell types, can be a potential strategy for tissue regeneration. However, the challenges like reproducibility, uncontrolled propagation and differentiation, isolation of specific kinds of cell and tumorigenic nature made these stem cells away from clinical application. Today, various types of stem cells like embryonic, fetal or gestational tissue, mesenchymal and induced-pluripotent stem cells are under investigation for their clinical application. Tissue engineering helps in configuring the stem cells to develop into a desired viable tissue, to use them clinically as a substitute for the conventional method. The use of stem cell-derived Extracellular Vesicles (EVs) is being studied to replace the stem cells, which decreases the immunological complications associated with the direct administration of stem cells. Tissue engineering also investigates various biomaterials to use clinically, either to replace the bones or as a scaffold to support the growth of stemcells/ tissue. Depending upon the need, there are various biomaterials like bio-ceramics, natural and synthetic biodegradable polymers to support replacement or regeneration of tissue. Like the other fields of science, tissue engineering is also incorporating the nanotechnology to develop nano-scaffolds to provide and support the growth of stem cells with an environment mimicking the Extracellular matrix (ECM) of the desired tissue. Tissue engineering is also used in the modulation of the immune system by using patient-specific Mesenchymal Stem Cells (MSCs) and by modifying the physical features of scaffolds that may provoke the immune system. This review describes the use of various stem cells, biomaterials and the impact of nanotechnology in regenerative medicine.


BMJ Open ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. e039579
Author(s):  
Anna K Moffat ◽  
Kerrie P Westaway ◽  
Jemisha Apajee ◽  
Oliver Frank ◽  
Russell Shute ◽  
...  

ObjectivesTo evaluate the impact of a patient-specific national programme targeting older Australians and health professionals that aimed to increase use of emollient moisturisers to reduce to the risk of skin tears.DesignA prospective cohort intervention.ParticipantsThe intervention targeted 52 778 Australian Government’s Department of Veterans’ Affairs patients aged over 64 years who had risk factors for wound development, and their general practitioners (GPs) (n=14 178).Outcome measuresAn interrupted time series model compared the rate of dispensing of emollients in the targeted cohort before and up to 23 months after the intervention. Commitment questions were included in self-report forms.ResultsIn the first month after the intervention, the rate of claims increased 6.3-fold (95% CI: 5.2 to 7.6, p<0.001) to 10 emollient dispensings per 1000 patients in the first month after the intervention. Overall, the intervention resulted in 10 905 additional patient-months of treatment. The increased rate of dispensing among patients who committed to talking to their GP about using an emollient was six times higher (rate ratio: 6.2, 95% CI: 4.4 to 8.7) than comparison groups.ConclusionsThe intervention had a sustained effect over 23 months. Veterans who responded positively to commitment questions had higher uptake of emollients than those who did not.


2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Faiz Ur Rehman ◽  
Muhammad Nasir

AbstractThe 2011 National Nutrition Survey of Pakistan revealed that 51% of the country’s population was consuming less than 2,100 calories a day. In the backdrop of rising food insecurity, hunger, and malnutrition in Pakistan, this study aims to measure the effects of indirect taxation on health outcomes of children (<5 years). More specifically, the impact of the incidence of General Sales Tax (GST) in the province of Punjab has been estimated on a child’s height and weight. The proponents of the uniform GST argue that the tax would not affect children because most food items consumed by children are exempted from the GST. However, the opponents believe that households, especially those belonging to the lower-income group, would reallocate resources away from children in the face of higher GST. To study these effects, we utilized three different waves (2007–08, 2011 & 2014) of Multiple Indicators Cluster Surveys (MICS). The results show that the tax incidence, and not the GST rate, has a significantly negative impact on children’s height-for-age Z-score (HAZ). No effect was found on the weight-for-age-z-score (WAZ). These results are robust to different specifications and exhibit considerable heterogeneity across different income groups. These findings suggest that the exemption of certain food items for children from the GST may not eliminate the negative effects of this tax on a child’s health. Thus, our study raises concerns about the long term welfare consequences of GST.


Vaccines ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 444
Author(s):  
Charles Stoecker

In the past two decades, most states in the United States have added authorization for pharmacists to administer some vaccinations. Expansions of this authority have also come with prescription requirements or other regulatory burdens. The objective of this study was to evaluate the impact of these expansions on influenza immunization rates in adults age 65 and over. A panel data, differences-in-differences regression framework to control for state-level unobserved confounders and shocks at the national level was used on a combination of a dataset of state-level statute and regulatory changes and influenza immunization data from the Behavioral Risk Factor Surveillance System. Giving pharmacists permission to vaccinate had a positive impact on adult influenza immunization rates of 1.4 percentage points for adults age 65 and over. This effect was diminished by the presence of laws requiring pharmacists to obtain patient-specific prescriptions. There was no evidence that allowing pharmacists to administer vaccinations led patients to have fewer annual check-ups with physicians or not have a usual source of health care. Expanding pharmacists’ scope of practice laws to include administering the influenza vaccine had a positive impact on influenza shot uptake. This may have implications for relaxing restrictions on other forms of care that could be provided by pharmacists.


2021 ◽  
pp. 1357633X2110259
Author(s):  
Kristin N Gmunder ◽  
Jose W Ruiz ◽  
Dido Franceschi ◽  
Maritza M Suarez

Introduction As coronavirus disease 2019 (COVID-19) hit the US, there was widespread and urgent implementation of telemedicine programs nationwide without much focus on the impact on patient populations with known existing healthcare disparities. To better understand which populations cannot access telemedicine during the coronavirus disease 2019 pandemic, this study aims to demographically describe and identify the most important demographic predictors of telemedicine visit completion in an urban health system. Methods Patient de-identified demographics and telemedicine visit data ( N = 362,764) between March 1, 2020 and October 31, 2020 were combined with Internal Revenue Service 2018 individual income tax data by postal code. Descriptive statistics and mixed effects logistic regression were used to determine impactful patient predictors of telemedicine completion, while adjusting for clustering at the clinical site level. Results Many patient-specific demographics were found to be significant. Descriptive statistics showed older patients had lower rates of completion ( p < 0.001). Also, Hispanic patients had statistically significant lower rates ( p < 0.001). Overall, minorities (racial, ethnic, and language) had decreased odds ratios of successful telemedicine completion compared to the reference. Discussion While telemedicine use continues to be critical during the coronavirus disease 2019 pandemic, entire populations struggle with access—possibly widening existing disparities. These results contribute large datasets with significant findings to the limited research on telemedicine access and can help guide us in improving telemedicine disparities across our health systems and on a wider scale.


Author(s):  
Jacqueline A Darrow ◽  
Amanda Calabro ◽  
Sara Gannon ◽  
Amanze Orusakwe ◽  
Rianne Esquivel ◽  
...  

Abstract Background Cerebrospinal fluid (CSF) biomarkers are increasingly used to confirm the accuracy of a clinical diagnosis of mild cognitive impairment or dementia due to Alzheimer disease (AD). Recent evidence suggests that fully automated assays reduce the impact of some preanalytical factors on the variability of these measures. This study evaluated the effect of several preanalytical variables common in clinical settings on the variability of CSF β-amyloid 1–42 (Aβ1–42) concentrations. Methods Aβ1–42 concentrations were measured using the LUMIPULSE G1200 from both freshly collected and frozen CSF samples. Preanalytic variables examined were: (1) patient fasting prior to CSF collection, (2) blood contamination of specimens, and (3) aliquoting specimens sequentially over the course of collection (i.e., CSF gradients). Results Patient fasting did not significantly affect CSF Aβ1–42 levels. While assessing gradient effects, Aβ1–42 concentrations remained stable within the first 5 1-mL aliquots. However, there is evidence of a gradient effect toward higher concentrations over successive aliquots. Aβ1–42 levels were stable when fresh CSF samples were spiked with up to 2.5% of blood. However, in frozen CSF samples, even 0.25% blood contamination significantly decreased Aβ1–42 concentrations. Conclusions The preanalytical variables examined here do not have significant effects on Aβ1–42 concentrations if fresh samples are processed within 2 h. However, a gradient effect can be observed on Aβ1–42 concentrations after the first 5 mL of collection and blood contamination has a significant impact on Aβ1–42 concentrations once specimens have been frozen.


2021 ◽  
Vol 11 (2) ◽  
pp. 834
Author(s):  
Marwa Mezghani ◽  
Nicola Hagemeister ◽  
Youssef Ouakrim ◽  
Alix Cagnin ◽  
Alexandre Fuentes ◽  
...  

Measuring knee biomechanics provides valuable clinical information for defining patient-specific treatment options, including patient-oriented physical exercise programs. It can be done by a knee kinesiography test measuring the three-dimensional rotation angles (3D kinematics) during walking, thus providing objective knowledge about knee function in dynamic and weight-bearing conditions. The purpose of this study was to assess whether 3D kinematics can be efficiently used to predict the impact of a physical exercise program on the condition of knee osteoarthritis (OA) patients. The prediction was based on 3D knee kinematic data, namely flexion/extension, adduction/abduction and external/internal rotation angles collected during a treadmill walking session at baseline. These measurements are quantifiable information suitable to develop automatic and objective methods for personalized computer-aided treatment systems. The dataset included 221 patients who followed a personalized therapeutic physical exercise program for 6 months and were then assigned to one of two classes, Improved condition (I) and not-Improved condition (nI). A 10% improvement in pain was needed at the 6-month follow-up compared to baseline to be in the improved group. The developed model was able to predict I and nI with 84.4% accuracy for men and 75.5% for women using a decision tree classifier trained with 3D knee kinematic data taken at baseline and a 10-fold validation procedure. The models showed that men with an impaired control of their varus thrust and a higher pain level at baseline, and women with a greater amplitude of internal tibia rotation were more likely to report improvements in their pain level after 6 months of exercises. Results support the effectiveness of decision trees and the relevance of 3D kinematic data to objectively predict knee OA patients’ response to a treatment consisting of a physical exercise program.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Monika Colombo ◽  
Yong He ◽  
Anna Corti ◽  
Diego Gallo ◽  
Stefano Casarin ◽  
...  

AbstractIn-stent restenosis (ISR) is the major drawback of superficial femoral artery (SFA) stenting. Abnormal hemodynamics after stent implantation seems to promote the development of ISR. Accordingly, this study aims to investigate the impact of local hemodynamics on lumen remodeling in human stented SFA lesions. Ten SFA models were reconstructed at 1-week and 1-year follow-up from computed tomography images. Patient-specific computational fluid dynamics simulations were performed to relate the local hemodynamics at 1-week, expressed in terms of time-averaged wall shear stress (TAWSS), oscillatory shear index and relative residence time, with the lumen remodeling at 1-year, quantified as the change of lumen area between 1-week and 1-year. The TAWSS was negatively associated with the lumen area change (ρ = − 0.75, p = 0.013). The surface area exposed to low TAWSS was positively correlated with the lumen area change (ρ = 0.69, p = 0.026). No significant correlations were present between the other hemodynamic descriptors and lumen area change. The low TAWSS was the best predictive marker of lumen remodeling (positive predictive value of 44.8%). Moreover, stent length and overlapping were predictor of ISR at follow-up. Despite the limited number of analyzed lesions, the overall findings suggest an association between abnormal patterns of WSS after stenting and lumen remodeling.


2021 ◽  
Vol 11 (2) ◽  
pp. 67-80
Author(s):  
Nguyen Quoc Anh ◽  
Duong Nguyen Thanh Phuong

This study investigates the impact of credit risk on the financial stability of Vietnamese commercial banks. The paper uses the Z-score to proxy the financial stability of banks. We use the data of 27 Vietnamese commercial banks on BankScope, during 2010 - 2019. The paper applied a dynamic panel data approach; the selected method is the difference GMM (DGMM). The key question discussed is which factor impacts on Z-score. Analysis results show the negative effect of non-performing loans on the financial stability of banks. When commercial banks have higher non-performing loans, the lower the financial stability is. Additionally, bank-specific variables such as equity on asset ratio, the return on equity, the size of the bank and set of macroeconomic variables affect the bank’s financial stability. Based on the analysis results, we imply relevant policies for the State Bank of Vietnam and commercial banks.


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