Diffusion Tensor MR Imaging

This unit reviews the physical principles and methodologies involved in diffusion‐weighted imaging (DWI) and diffusion tensor imaging (DTI) for clinical applications. Diffusion‐sensitive MRI noninvasively provides insight into processes and microscopic cellular structures that alter molecular water mobility. Formalism to extend the Bloch equation to include effects of random translational motion through field gradients is reviewed. Definition of key acquisition parameters is also reviewed along with common methods to calculate and display tissue diffusion properties in a variety of image formats. Characterization of potential directional‐dependence of diffusion (i.e., anisotropy), such as that which exists in white matter, requires DTI. Diffusion tensor formalism and measurement techniques then reduce the diffusion tensor into standard anisotropy quantities that are summarized along with commonly used methods to depict directional information in an image format.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/145343/1/cpmib0801.pd

VALIDATING CONTINGENT VALUATION WITH SURVEYS OF EXPERTS

Contingent-valuation estimates for white-water boating passengers are compared with Likert ratings by river guides. The approach involves asking whether passengers and their guides ordinally rank alternative flows the same. The National Oceanic and Atmospheric Administration's Contingent Valuation Panel (1993) suggested "one might want to compare its (contingent-valuation's) outcome with that provided by a panel of experts." River guides constitute a counterfactual panel of "experts." For commercial trips, optimum flows are 34,000 cfs and 31,000 cfs for passengers and guides, and the comparable figures for private trips are 28,000 cfs and 29,000 cfs. In the NOAA Panel framework, passengers can evaluate the consequences of various river flows and translate this into contingent-valuation responses.Resource /Energy Economics and Policy,

Reduced Interhemispheric Functional Connectivity in the Motor Cortex during Rest in Limb-Onset Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder of motor neurons that leads to paralysis and eventually death. There is evidence that atrophy occurs in the primary motor cortex (M1), but it is unclear how the disease affects the intrinsic connectivity of this structure. Thus, the goal of this study was to examine interhemispheric coupling of low frequency blood-oxygen-level dependent (BOLD) signal fluctuations in M1 using functional connectivity magnetic resonance imaging during rest. Because disease progression is rapid, high-functioning patients were recruited to assess neural changes in the relatively early stages of ALS. Twenty patients with limb-onset ALS participated in this study. A parceling technique was employed to segment both precentral gyri into multiple regions of interest (ROI), thus increasing sensitivity to detect changes that exist along discretely localized regions of the motor cortex. We report an overall systemic decrease in functional connectivity between right and left motor cortices in patients with limb-onset ALS. Additionally, we observed a pronounced disconnection between dorsal ROI pairs in the ALS group compared to the healthy control group. Furthermore, measures of limb functioning correlated with the connectivity data from dorsal ROI pairs in the ALS group, suggesting a symptomatic relationship with interhemispheric M1 connectivity

Parent-Focused Childhood Obesity Intervention Improves Family Functioning and Children\u27s Well-Being

An Extension-implemented parent-focused childhood obesity intervention designed to improve family functioning around healthful eating and exercise was evaluated. Thirty-six parents and their children, aged 5–13, were randomized to a 12-week intervention condition or control condition. Intervention parents, compared to control group parents, felt more confident in promoting children\u27s healthful eating and exercise, worried less about their children\u27s weight, and engaged in fewer counterproductive parenting behaviors. The children of these parents, as compared to children of control group parents, lost weight and displayed better social-emotional functioning. These results highlight Extension\u27s important role in disseminating evidence-based childhood obesity interventions