MR fingerprinting allows rapid simultaneous quantification of T1 and T2 relaxation times. This study assessed the utility of MR fingerprinting in differentiating common types of adult intra-axial ...brain tumors.
MR fingerprinting acquisition was performed in 31 patients with untreated intra-axial brain tumors: 17 glioblastomas, 6 World Health Organization grade II lower grade gliomas, and 8 metastases. T1, T2 of the solid tumor, immediate peritumoral white matter, and contralateral white matter were summarized within each ROI. Statistical comparisons on mean, SD, skewness, and kurtosis were performed by using the univariate Wilcoxon rank sum test across various tumor types. Bonferroni correction was used to correct for multiple-comparison testing. Multivariable logistic regression analysis was performed for discrimination between glioblastomas and metastases, and area under the receiver operator curve was calculated.
Mean T2 values could differentiate solid tumor regions of lower grade gliomas from metastases (mean, 172 ± 53 ms, and 105 ± 27 ms, respectively;
= .004, significant after Bonferroni correction). The mean T1 of peritumoral white matter surrounding lower grade gliomas differed from peritumoral white matter around glioblastomas (mean, 1066 ± 218 ms, and 1578 ± 331 ms, respectively;
= .004, significant after Bonferroni correction). Logistic regression analysis revealed that the mean T2 of solid tumor offered the best separation between glioblastomas and metastases with an area under the curve of 0.86 (95% CI, 0.69-1.00;
< .0001).
MR fingerprinting allows rapid simultaneous T1 and T2 measurement in brain tumors and surrounding tissues. MR fingerprinting-based relaxometry can identify quantitative differences between solid tumor regions of lower grade gliomas and metastases and between peritumoral regions of glioblastomas and lower grade gliomas.
Congenital generalized lipodystrophy (CGL) is an autosomal recessive disorder with two major subtypes. Variants in AGPAT2 result in CGL type 1 with milder manifestations, whereas BSCL2 variants cause ...CGL type 2 with more severe features. Muscle hypertrophy caused by lack of adipose tissue is present early in life in CGL patients. Our aim was to investigate 10 CGL patients from 7 different countries and report genotype–phenotype relationships. Genetic analysis identified disease‐causing variants in AGPAT2 (five patients) and in BSCL2 (five patients), including three novel variants; c.134C>A (p.Ser45*), c.216C>G (p.Tyr72*) in AGPAT2 and c.458C>A (p.Ser153*) in BSCL2. We also report possible novel clinical features such as anemia, breast enlargement, steatorrhea, intraventricular hemorrhage and nephrolithiasis in CGL patients. Generalized lipodystrophy and muscular hypertrophy were the only features in all of our patients. Hepatomegaly was the second common feature. Some manifestations were exclusively noticed in our CGL2 patients; hypertrichosis, high‐pitched voice and umbilical hernia. Bone cysts and history of seizures were noticed only in CGL1 patients. The findings of this study expand our knowledge of genotype–phenotype correlations in CGL patients. These results have important clinical applications in diagnosis and management of the CGL patients as well as in genetic counseling in families at‐risk.
The most challenging and time-consuming step of TIPS procedures is obtaining appropriate portal vein (PV) access. Given the lack of real-time direct target visualization, conventional fluoroscopic ...guidance requires multiple passes, contributing to complications. In comparison, intravascular ultrasound (IVUS) guidance during TIPS procedures provides direct visualization of hepatic structures and real-time guidance for PV puncture. IVUS guidance during TIPS creation improves procedural metrics such as radiation dose, contrast agent volume, procedure time, and technical success rate and is particularly beneficial in technically challenging cases (e.g., in patients portal vein thrombosis, small or variant portal vein anatomy, Budd-Chiari syndrome, or liver masses). The purpose of this review is to summarize current IVUS technology, describe the technical aspects of IVUS-guided TIPS creation, and discuss the clinical indications for and benefits of using IVUS for TIPS creation, while presenting available evidence supporting the technique's use. Given the improved safety profile and overall success rate in comparison with conventional guidance methods, IVUS guidance has the future potential to become the standard practice for TIPS placement.
Since its inception in the early 1990s, the Global Leadership and Organizational Behavior Effectiveness (GLOBE) project has investigated the complex relationship between societal culture and ...organizational behavior. The focus of this paper is on leadership, specifically what we know and have learned from the GLOBE project so far. Among other findings, we demonstrate that national culture indirectly influences leadership behaviors through the leadership expectations of societies. In other words, executives tend to lead in a manner more or less consistent with the leadership prototypes endorsed within their particular culture. In turn, leaders who behave according to expectations are most effective. We also found that some leadership behaviors are universally effective such as charismatic/value-based leadership; others are much more culturally sensitive such as participative leadership. Finally, we identified truly superior (and also truly inferior) CEOs by the degree to which their behaviors exceed (or fail to meet) their society's expectations. All in all, understanding national culture gives us a heads-up as to which kinds of leadership will likely be enacted and effective in each society. We believe that the GLOBE journey has helped us understand the complex, tricky, and fascinating relationships among societal culture, organizational behavior, and leadership processes.
In recent years, sociologists pay special attention to the challenging issue of sexual discrimination which has been converted to a hot topic nowadays. The main issue is why women are inhibited to ...attend in a special socio cultural events despite of presence law, rule and regulation in that area. So, in order to find out the answer of this question, the authors decided to conduct an analytic short communication using a search in the literature. As the main problem was emerged in Iran, besides reviewing International documents and conventions allocated to women, national – Iranian- literature such as academic papers, reports, newspapers and magazines were also searched. Comparing the written documents to real situations showed inconsistency; because although there was no limitation for participating women in such activities, the execution of laws has been failed. The barriers seem to be categorized in Macro and Micro levels which could be resolved by clarifying, defining and planning specific strategies in their related area. Obviously, in depth exploration of the major concept need qualitative studies.
Purpose To develop and evaluate an examination consisting of magnetic resonance (MR) fingerprinting-based T1, T2, and standard apparent diffusion coefficient (ADC) mapping for multiparametric ...characterization of prostate disease. Materials and Methods This institutional review board-approved, HIPAA-compliant retrospective study of prospectively collected data included 140 patients suspected of having prostate cancer. T1 and T2 mapping was performed with fast imaging with steady-state precession-based MR fingerprinting with ADC mapping. Regions of interest were drawn by two independent readers in peripheral zone lesions and normal-appearing peripheral zone (NPZ) tissue identified on clinical images. T1, T2, and ADC were recorded for each region. Histopathologic correlation was based on systematic transrectal biopsy or cognitively targeted biopsy results, if available. Generalized estimating equations logistic regression was used to assess T1, T2, and ADC in the differentiation of (a) cancer versus NPZ, (b) cancer versus prostatitis, (c) prostatitis versus NPZ, and (d) high- or intermediate-grade tumors versus low-grade tumors. Analysis was performed for all lesions and repeated in a targeted biopsy subset. Discriminating ability was evaluated by using the area under the receiver operating characteristic curve (AUC). Results In this study, 109 lesions were analyzed, including 39 with cognitively targeted sampling. T1, T2, and ADC from cancer (mean, 1628 msec ± 344, 73 msec ± 27, and 0.773 × 10
mm
/sec ± 0.331, respectively) were significantly lower than those from NPZ (mean, 2247 msec ± 450, 169 msec ± 61, and 1.711 × 10
mm
/sec ± 0.269) (P < .0001 for each) and together produced the best separation between these groups (AUC = 0.99). ADC and T2 together produced the highest AUC of 0.83 for separating high- or intermediate-grade tumors from low-grade cancers. T1, T2, and ADC in prostatitis (mean, 1707 msec ± 377, 79 msec ± 37, and 0.911 × 10
mm
/sec ± 0.239) were significantly lower than those in NPZ (P < .0005 for each). Interreader agreement was excellent, with an intraclass correlation coefficient greater than 0.75 for both T1 and T2 measurements. Conclusion This study describes the development of a rapid MR fingerprinting- and diffusion-based examination for quantitative characterization of prostatic tissue.
RSNA, 2017 Online supplemental material is available for this article.
Purpose
This is a radiomics study investigating the ability of texture analysis of MRF maps to improve differentiation between intra-axial adult brain tumors and to predict survival in the ...glioblastoma cohort.
Methods
Magnetic resonance fingerprinting (MRF) acquisition was performed on 31 patients across 3 groups: 17 glioblastomas, 6 low-grade gliomas, and 8 metastases. Using regions of interest for the solid tumor and peritumoral white matter on T1 and T2 maps, second-order texture features were calculated from gray-level co-occurrence matrices and gray-level run length matrices. Selected features were compared across the three tumor groups using Wilcoxon rank-sum test. Receiver operating characteristic curve analysis was performed for each feature. Kaplan-Meier method was used for survival analysis with log rank tests.
Results
Low-grade gliomas and glioblastomas had significantly higher run percentage, run entropy, and information measure of correlation 1 on T1 than metastases (
p
< 0.017). The best separation of all three tumor types was seen utilizing inverse difference normalized and homogeneity values for peritumoral white matter in both T1 and T2 maps (
p
< 0.017). In solid tumor T2 maps, lower values in entropy and higher values of maximum probability and high-gray run emphasis were associated with longer survival in glioblastoma patients (
p
< 0.05). Several texture features were associated with longer survival in glioblastoma patients on peritumoral white matter T1 maps (
p
< 0.05).
Conclusion
Texture analysis of MRF-derived maps can improve our ability to differentiate common adult brain tumors by characterizing tumor heterogeneity, and may have a role in predicting outcomes in patients with glioblastoma.
This paper assesses whether societal culture moderates the relationship between human resource management (HRM) practices and organizational performance. Drawing on matched employer–employee data ...from 387 organizations and 7187 employees in 14 countries, our findings show a positive relationship between HRM practices combined in High-Performance Work Systems (HPWS) and organizational performance across societal cultures. Three dimensions of societal culture assessed (power distance, in-group collectivism, and institutional collectivism) did not moderate this relationship. Drawing on the Ability–Motivation–Opportunity (AMO) model, we further consider the effectiveness of three bundles of HRM practices (skill-enhancing, motivation-enhancing, and opportunity-enhancing practices). This analysis shows opportunity-enhancing practices (e.g., participative work design and decision-making) are less effective in high-power-distance cultures. Nevertheless, in markedly different countries we find combinations of complementary HPWS and bundles of AMO practices appear to outweigh the influence of societal culture and enhance organizational performance.
The purpose of this study is to examine the link between training and the perceived contribution of training to enhanced productivity or cost reduction. Using data from 92 Canadian organizations, the ...results show that organizations with higher percentage of trained employees are likely to perceive training to be beneficial. In addition, the results indicate that perceived benefits of training are further enhanced by the presence of human resources management practices that either encourages employees to undertake training (the motivation bundle) and/or provides a systematic assessment of post-training effectiveness (the assessment bundle). The evidence however also shows that open climate as measured by autonomous work systems nullifies the benefits of training, suggesting that under such a structure, employees are unlikely to put in practice the skills they acquired during training.
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