Social Media in B2B Financial Services: A Matter of Trust and Responsiveness?

This study explores satisfaction with Virtual Communities in a Financial Services setting. It presents an empirical exploration that seeks to explain how external variables, such as information quality and system quality of a VC, affect beliefs, such asusefulness, ease of use, responsiveness, and trust, which in turn shape satisfaction. As such, it contributes to the growing body of knowledge on Social Media, in particular addressing the relatively unexplored domain of Business-to-Business (B2B) when individuals act on behalf of a company instead of their own interests

Reproducibility of quantitative indices of lung function and microstructure from 129Xe chemical shift saturation recovery (CSSR) MR spectroscopy

Purpose To evaluate the reproducibility of indices of lung microstructure and function derived from 129Xe chemical shift saturation recovery (CSSR) spectroscopy in healthy volunteers and patients with chronic obstructive pulmonary disease (COPD), and to study the sensitivity of CSSR-derived parameters to pulse sequence design and lung inflation level. Methods Preliminary data were collected from five volunteers on three occasions, using two implementations of the CSSR sequence. Separately, three volunteers each underwent CSSR at three different lung inflation levels. After analysis of these preliminary data, five COPD patients were scanned on three separate days, and nine age-matched volunteers were scanned three times on one day, to assess reproducibility. Results CSSR-derived alveolar septal thickness (ST) and surface-area-to-volume (S/V) ratio values decreased with lung inflation level (P < 0.001; P = 0.057, respectively). Intra-subject standard deviations of ST were lower than the previously measured differences between volunteers and subjects with interstitial lung disease. The mean coefficient of variation (CV) values of ST were 3.9 ± 1.9% and 6.0 ± 4.5% in volunteers and COPD patients, respectively, similar to CV values for whole-lung carbon monoxide diffusing capacity. The mean CV of S/V in volunteers and patients was 14.1 ± 8.0% and 18.0 ± 19.3%, respectively. Conclusion 129Xe CSSR presents a reproducible method for estimation of alveolar septal thickness

Regional ventilation changes in the lung: Treatment response mapping by using hyperpolarized gas MR imaging as a quantitative biomarker

Purpose: To assess the magnitude of regional response to respiratory therapeutics in the lungs using Treatment Response Mapping (TRM) with hyperpolarized gas MRI. TRM is used to quantify regional physiological response in asthmatic adults using a bronchodilator challenge. Methods: The study was approved by the national research ethics committee and performed with informed consent. Imaging was performed in 20 adult asthmatic patients using hyperpolarized 3He ventilation MRI. Two sets of baseline images were acquired before inhalation of a bronchodilator (Inhaled Salbutamol 400 mcg) and one set was acquired after. All images were registered for voxelwise comparison. Regional treatment response, ΔR(r), is calculated as the difference in regional gas distribution (R(r) = ratio of inhaled gas to total volume of a voxel when normalized for lung inflation volume) before and after intervention. A voxelwise activation threshold from the variability of the baseline images was applied to ΔR(r) maps. The summed global TRM (ΔRnet) was then used as global lung index for comparison with metrics of bronchodilator response measured using spirometry and the global imaging metric, percentage ventilated volume (%VV). Results: ΔRnet showed significant correlation (p<0.01) with changes in FEV1 (r=0.70), FVC (r=0.84) and %VV (r=0.56). A significant (p<0.01) positive treatment effect was detected by all metrics, however ΔRnet showed a lower inter-subject coefficient of variation (CV=64%) than all of the other tests (CV≥99%). Conclusions: TRM provides regional quantitative information on changes in inhaled gas ventilation in response to therapy. This method could be used as sensitive regional outcome metric of novel respiratory interventions. Online supplemental material is available for this article

Multiple breath washout of hyperpolarized 129Xe and 3He in human lungs with 3D bSSFP imaging

Purpose: (i) To compare quantitative fractional ventilation measurements from multiple breath washout imaging (MBW-I) using hyperpolarized (HP) 3He with both spoiled gradient echo (SPGR) and balanced steady-state free-precession (bSSFP) 3D pulse sequences and (ii) to evaluate the feasibility of MBW-I with HP 129Xe. Methods: Seven healthy volunteers were scanned using 3He MBW-I with 3D SPGR and bSSFP sequences. Five also underwent MBW-I with 129Xe. A dual-tuned coil was used to acquire MBW-I data from both nuclei in the same subject position, enabling direct comparison of regional information. Results: High-quality MBW images were obtained with bSSFP sequences using a reduced dose (100ml) of inhaled hyperpolarized 3He. 3D MBW-I with 129Xe was also successfully demonstrated with a bSSFP sequence. Regional quantitative ventilation measures derived from 3He and 129Xe MBW-I correlated well in all subjects (p<0.001) with mean Pearson’s correlation coefficients of r=0.61 and r=0.52 for 3He SPGR-bSSFP and 129Xe-3He (bSSFP) comparisons. The average inter-volunteer mean difference (and standard deviation) in fractional ventilation in SPGR-bSSFP and 129Xe-3He comparisons was 15% (28%) and 9% (38%), respectively. Conclusions: Improved sensitivity in MBW-I can be achieved with polarization-efficient bSSFP sequences. Same scan-session 3D MBW-I with 3He and 129Xe has been demonstrated using a dual-tuned coil