What is Family Preservation and Why Does it Matter?

This paper describes competing ideas about family preservation, defined both as a defined program of social services and a philosophical approach to helping troubled families. A straightforward definition has become almost impossible because the phrase has taken on so many different meanings, provoking controversy about its "real" meaning and value. Indeed, "family preservation" has become the proverbial elephant whose splendors and horrors are described with great certainty by those impressed by only one of its aspects. While skirmishes between "child savers" and "family preservers" have been part of the child welfare field since its beginning at the turn of the last century, recent debates over family preservation have been especially heated, generating more confusion and animosity than might be expected from the ranks of the small and usually mild-mannered social work profession. The debate is so heated that the director of one of the nation's largest child welfare agencies said recently that he is afraid to "even use the two words on the same page." <1> While the debate about the value of family preservation is unresolved, experimentation with different approaches to service delivery over the last two decades has helped to lay the groundwork for a resurgence of interest in family and community-centered reforms. Better understanding of the family preservation "debates" may be helpful if these reforms are to be successful over the long term. The paper discusses the competing ideas, values, and perceptions that have led observers to their different understandings of family preservation. It briefly chronicles the history of child welfare and examines key theories that have helped lay the groundwork for the resurgence of interest in family-centered services. It concludes with observations about how the competing values at stake in family preservation may affect the next generation of reforms.

NOVEL PHANTOMS AND POST-PROCESSING FOR DIFFUSION SPECTRUM IMAGING

High Angular Resolution Diffusion Imaging (HARDI) techniques, including Diffusion Spectrum Imaging (DSI), have been proposed to resolve crossing and other complex fiber architecture in the human brain white matter. In these methods, directional information of diffusion is inferred from the peaks in the orientation distribution function (ODF). Extensive studies using histology on macaque brain, cat cerebellum, rat hippocampus and optic tracts, and bovine tongue are qualitatively in agreement with the DSI-derived ODFs and tractography. However, there are only two studies in the literature which validated the DSI results using physical phantoms and both these studies were not performed on a clinical MRI scanner. Also, the limited studies which optimized DSI in a clinical setting, did not involve a comparison against physical phantoms. Finally, there is lack of consensus on the necessary pre- and post-processing steps in DSI; and ground truth diffusion fiber phantoms are not yet standardized. Therefore, the aims of this dissertation were to design and construct novel diffusion phantoms, employ post-processing techniques in order to systematically validate and optimize (DSI)-derived fiber ODFs in the crossing regions on a clinical 3T MR scanner, and develop user-friendly software for DSI data reconstruction and analysis. Phantoms with a fixed crossing fiber configuration of two crossing fibers at 90° and 45° respectively along with a phantom with three crossing fibers at 60°, using novel hollow plastic capillaries and novel placeholders, were constructed. T2-weighted MRI results on these phantoms demonstrated high SNR, homogeneous signal, and absence of air bubbles. Also, a technique to deconvolve the response function of an individual peak from the overall ODF was implemented, in addition to other DSI post-processing steps. This technique greatly improved the angular resolution of the otherwise unresolvable peaks in a crossing fiber ODF. The effects of DSI acquisition parameters and SNR on the resultant angular accuracy of DSI on the clinical scanner were studied and quantified using the developed phantoms. With a high angular direction sampling and reasonable levels of SNR, quantification of a crossing region in the 90°, 45° and 60° phantoms resulted in a successful detection of angular information with mean ± SD of 86.93°±2.65°, 44.61°±1.6° and 60.03°±2.21° respectively, while simultaneously enhancing the ODFs in regions containing single fibers. For the applicability of these validated methodologies in DSI, improvement in ODFs and fiber tracking from known crossing fiber regions in normal human subjects were demonstrated; and an in-house software package in MATLAB which streamlines the data reconstruction and post-processing for DSI, with easy to use graphical user interface was developed. In conclusion, the phantoms developed in this dissertation offer a means of providing ground truth for validation of reconstruction and tractography algorithms of various diffusion models (including DSI). Also, the deconvolution methodology (when applied as an additional DSI post-processing step) significantly improved the angular accuracy of the ODFs obtained from DSI, and should be applicable to ODFs obtained from the other high angular resolution diffusion imaging techniques.