Late Gadolinium Enhancement Cardiovascular Magnetic Resonance Assessment of Substrate for Ventricular Tachycardia With Hemodynamic Compromise.

Background: The majority of data regarding tissue substrate for post myocardial infarction (MI) VT has been collected during hemodynamically tolerated VT, which may be distinct from the substrate responsible for VT with hemodynamic compromise (VT-HC). This study aimed to characterize tissue at diastolic locations of VT-HC in a porcine model. Methods: Late Gadolinium Enhancement (LGE) cardiovascular magnetic resonance (CMR) imaging was performed in eight pigs with healed antero-septal infarcts. Seven pigs underwent electrophysiology study with venous arterial-extra corporeal membrane oxygenation (VA-ECMO) support. Tissue thickness, scar and heterogeneous tissue (HT) transmurality were calculated at the location of the diastolic electrograms of mapped VT-HC. Results: Diastolic locations had median scar transmurality of 33.1% and a median HT transmurality 7.6%. Diastolic activation was found within areas of non-transmural scar in 80.1% of cases. Tissue activated during the diastolic component of VT circuits was thinner than healthy tissue (median thickness: 5.5 mm vs. 8.2 mm healthy tissue, p < 0.0001) and closer to HT (median distance diastolic tissue: 2.8 mm vs. 11.4 mm healthy tissue, p < 0.0001). Non-scarred regions with diastolic activation were closer to steep gradients in thickness than non-scarred locations with normal EGMs (diastolic locations distance = 1.19 mm vs. 9.67 mm for non-diastolic locations, p < 0.0001). Sites activated late in diastole were closest to steep gradients in tissue thickness. Conclusions: Non-transmural scar, mildly decreased tissue thickness, and steep gradients in tissue thickness represent the structural characteristics of the diastolic component of reentrant circuits in VT-HC in this porcine model and could form the basis for imaging criteria to define ablation targets in future trials.

Comparative Assessment of Hand Joint Ultrasound Findings in Symptomatic Patients with Systemic Lupus Erythematosus and Sjögren's Syndrome: A Pilot Study.

Systemic lupus erythematosus (SLE) and primary Sjögren's syndrome (SS) can be associated with inflammatory arthritis, which is underdiagnosed by clinical examination. The aim of this cross-sectional, observational study was to compare, for the first time, the ultrasound (US)-detected joint abnormalities in these two diseases and to define the role of US in patient management. Participants had SLE (n = 18) and SS (n = 23), symptoms of hand joint pain and no previous diagnosis of arthritis. Data on disease activity, duration, damage scores, inflammatory and serologic markers, treatment and clinical and ultrasound parameters (derived from the assessment of 902 joints) were analysed and correlated using descriptive statistics, correlation tests and regression models. Subclinical synovitis/tenosynovitis was detected in 44.4% of SLE patients and 21.7% of SS patients (p = 0.23). There was no significant correlation between either the total Power Doppler score or the total grey-scale score and disease activity scores (British Isles Lupus Assessment Group index and European League Against Rheumatism Sjögren's syndrome disease activity index). Both damage scores (Systemic Lupus International Collaborating Clinics index and Sjögren's syndrome disease damage index) correlated with the total grey-scale synovitis score. Significant proportions of the participants with SLE and SS had erosions (55.6% and 34.8%, respectively, p = 0.184) and osteophytes (61.1% vs. 60.9%, p = 0.98) in at least one joint. The lack of correlation between disease activity scores and US outcome measures indicated their limitations in diagnosing subclinical synovitis in SLE and SS patients. Future research is needed to determine if the development of erosions could be prevented by early diagnosis and prompt treatment of inflammatory arthritis associated with SLE and SS.

Light path-length distributions within the retina.

A Monte Carlo simulation of light propagation through the retina has been developed to understand the path-length distributions within the retinal vessel. For full-field illumination, the path-length distribution within the vessel comprises directly backscattered light and light that has passed once or twice through the vessel. The origins of these light path-length distributions can be better understood by investigating different combinations of single-point illumination and detection positions. Perhaps the most significant observation is that illumination at the edges of the vessel, rather than over the whole field of view, and detection directly above the vessel capture only the light that has taken a single pass through the vessel. This path-length distribution is tightly constrained around the diameter of the vessel and can potentially provide enhancements for oxygen saturation imaging. The method could be practically implemented using an offset-pinhole confocal imaging system or structured light illumination.

Engaging with economic evaluation methods: insights from small and medium enterprises in the UK medical devices industry after training workshops.

BACKGROUND: With increased governmental interest in value assessment of technologies and where medical device manufacturers are finding it increasingly necessary to become more familiar with economic evaluation methods, the study sought to explore the levels of health economics knowledge within small and medium-sized enterprises (SMEs) and to scope strategies they employ to demonstrate the value of their products to purchasers. METHODS: A short questionnaire was completed by participants attending one of five workshops on product development in the medical device sector that took place in England between 2007 and 2011. From all responses obtained, a large proportion of participants were based in SMEs (N = 43), and these responses were used for the analysis. Statistical analysis using non-parametric tests was performed on questions with approximately interval scales. Qualitative data from participant responses were analysed to reveal emerging themes. RESULTS: The questionnaire results revealed that 60% of SME participants (mostly company directors or managers, including product or project managers) rated themselves as having low or no knowledge of health economics prior to the workshops but the rest professed at least medium knowledge. Clinical trials and cost analyses or cost-effectiveness studies were the most highly cited means by which SMEs aim to demonstrate value of products to purchasers. Purchasers were perceived to place most importance on factors of safety, expert opinion, cost-effectiveness and price. However many companies did not utilise formal decision-making tools to prioritise these factors. There was no significant dependence of the use of decision-making tools in general with respect to professed knowledge of health economics methods. SMEs did not state a preference for any particular aspect of potential value when deciding whether to develop a product. A majority of SMEs stated they would use a health economics tool. Research and development teams or marketing and sales departments would most likely use one. CONCLUSION: This study points to the need for further research into the education requirements of SMEs in the area of Health Technology Assessment (HTA) and also for investigation into how SMEs engage with existing HTA processes as required by assessors such as NICE.

Experimental and theoretical evaluation of rotating orthogonal polarization imaging.

Rotating orthogonal polarization imaging is a new technique that provides quantitative measurements of the polarization properties of scattering media, such as tissue, which are free from surface reflections. The technique is investigated using both experiments and Monte Carlo simulations of a polarizing target embedded within a scattering medium. The technique is sensitive to the polarization properties of the target up to a depth of 17 mean free paths. Preliminary images of bovine tendon, lamb tendon, chicken breast, and human skin are also demonstrated.

Economic growth and the biological standard of living in China, 1880-1930.

Recent scholarship has revised the once pessimistic view of the Chinese economy in the late 19th and early 20th centuries, but controversy surrounds the distribution effects of economic growth. Did livelihoods improve? Who benefited from the growth? Which regions were better off? Past studies infer an improved standard of living based on sparse data for wages, the output of cotton textiles and movements in grain prices. Height data provide an additional measure of the change in welfare, specifically the biological standard of living. This paper draws on the health examination records conducted at various Chinese government enterprises and agencies during the 1930s and 1940s, and shows a modest improvement in this measure of human welfare in some regions of China from the 1890s to the 1920s.