Feasibility of MR-Based Body Composition Analysis in Large Scale Population Studies

Introduction Quantitative and accurate measurements of fat and muscle in the body are important for prevention and diagnosis of diseases related to obesity and muscle degeneration. Manually segmenting muscle and fat compartments in MR body-images is laborious and time-consuming, hindering implementation in large cohorts. In the present study, the feasibility and success-rate of a Dixon-based MR scan followed by an intensity-normalised, non-rigid, multi-atlas based segmentation was investigated in a cohort of 3,000 subjects. Materials and Methods 3,000 participants in the in-depth phenotyping arm of the UK Biobank imaging study underwent a comprehensive MR examination. All subjects were scanned using a 1.5 T MR-scanner with the dual-echo Dixon Vibe protocol, covering neck to knees. Subjects were scanned with six slabs in supine position, without localizer. Automated body composition analysis was performed using the AMRA Profiler™ system, to segment and quantify visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (ASAT) and thigh muscles. Technical quality assurance was performed and a standard set of acceptance/rejection criteria was established. Descriptive statistics were calculated for all volume measurements and quality assurance metrics. Results Of the 3,000 subjects, 2,995 (99.83%) were analysable for body fat, 2,828 (94.27%) were analysable when body fat and one thigh was included, and 2,775 (92.50%) were fully analysable for body fat and both thigh muscles. Reasons for not being able to analyse datasets were mainly due to missing slabs in the acquisition, or patient positioned so that large parts of the volume was outside of the field-of-view. Discussion and Conclusions In conclusion, this study showed that the rapid UK Biobank MR-protocol was well tolerated by most subjects and sufficiently robust to achieve very high success-rate for body composition analysis. This research has been conducted using the UK Biobank Resource.

The War at Home

The reform of cities spaces and housing has been a key issue with campaigners on the left for more than a century. These campaigns have found allies in the work of socially committed photographers from Jacob Riis at the turn of the twentieth century to Margaret Morton and Camilo Jose Vergara today. Globally the current phase of neo-liberalism has brought its own issues to the city as ‘regeneration’ strategies dispossess the urban poor in areas that are potentially lucrative to real estate development. In this process known as ‘accumulation by dispossession’ large profits are accumulated in the process of dispossessing people of their land, rights and homes. Central to the theoretical component of this paper, is an interrogation of contemporary ideas on the production and photographic representation of urban space. The research hence questions photography’s ability to make ‘legible’ the key drivers of today’s emergent terrains and to visualize their connections to the networks of power and capital that articulate the current political economy (Sassen 2011:36). One strand here will be the ‘fleshing out’ of the cultural practices behind photographers mediating urban development (Jones 2013: 1.2). Alongside current corporate depictions historical precedents will be discussed. Photographers as far back as Charles Marville in Paris of the 1850’s have documented urban reconstruction (Kennel 2013). Often employed by those undertaking the demolition, these photographic images frequently suppress certain narratives of the unbuilding process. Acting as a propaganda tool they eliminate the impact on the lives of inhabitants or the economic realities driving the valorization of reconstruction schemes (James 2004). Reformist documentary images have also played their part in justifying large-scale urban reconstruction that involved the eventual displacement of existing communities (Rose 1997: Blaikie 2006). Focusing on the gentrification of social housing in Pendleton, Salford (Greater Manchester) the presentation will explore the artists’ own work through a critical discussion, photographic images and excerpts from site writing they’ve undertaken in the area since 2004. It asks can an alternative photographic and visual strategy provide a meaningful political counter narrative to combat persuasive corporate discourses on ‘urban revitalization’? The paper will explore strategies and techniques of witnessing and ask whether these types of record can counter neo-liberal visualizations that mediate the material transformation of city areas. Can such representations begin a critical conversation about the nature of urban change and who benefits from these transformations (Wyly 2010)? Can we develop this critical photography into a type of practice that moves beyond generalisations and talks about social relations though an ‘explicit analysis of society’ (Rosler 2004:195).