Increasing the Analytical Accessibility of Multishell and Diffusion Spectrum Imaging Data Using Generalized Q-Sampling Conversion

Many diffusion MRI researchers, including the Human Connectome Project (HCP), acquire data using multishell (e.g., WU-Minn consortium) and diffusion spectrum imaging (DSI) schemes (e.g., USC-Harvard consortium). However, these data sets are not readily accessible to high angular resolution diffusion imaging (HARDI) analysis methods that are popular in connectomics analysis. Here we introduce a scheme conversion approach that transforms multishell and DSI data into their corresponding HARDI representations, thereby empowering HARDI-based analytical methods to make use of data acquired using non-HARDI approaches. This method was evaluated on both phantom and in-vivo human data sets by acquiring multishell, DSI, and HARDI data simultaneously, and comparing the converted HARDI, from non-HARDI methods, with the original HARDI data. Analysis on the phantom shows that the converted HARDI from DSI and multishell data strongly predicts the original HARDI (correlation coefficient > 0.9). Our in-vivo study shows that the converted HARDI can be reconstructed by constrained spherical deconvolution, and the fiber orientation distributions are consistent with those from the original HARDI. We further illustrate that our scheme conversion method can be applied to HCP data, and the converted HARDI do not appear to sacrifice angular resolution. Thus this novel approach can benefit all HARDI-based analysis approaches, allowing greater analytical accessibility to non-HARDI data, including data from the HCP

Switching to the rubber hand

Inducing the rubber hand illusion (RHI) requires that participants look at an imitation hand while it is stroked in synchrony with their occluded biological hand. Previous explanations of the RHI have emphasized multisensory integration, and excluded higher cognitive functions. We investigated the relationship between the RHI and higher cognitive functions by experimentally testing task switch (as measured by switch cost) and mind wandering (as measured by SART score); we also included a questionnaire for attentional control that comprises two subscales, attention-shift and attention-focus. To assess experience of RHI, the Botvinick and Cohen (1998) questionnaire was used and illusion onset time was recorded. Our results indicate that rapidity of onset reliably indicates illusion strength. Regression analysis revealed that participants evincing less switch cost and higher attention-shift scores had faster RHI onset times, and that those with higher attention-shift scores experienced the RHI more vividly. These results suggest that the multi-sensory hypothesis is not sufficient to explain the illusion: higher cognitive functions should be taken into account when explaining variation in the experience of ownership for the rubber hand

SINGLE VERSUS MULTIPLE OBJECTIVE RECREATION TRIPS: A SPLIT-SAMPLE MULTI-SITE ANALYSIS

A random utility model of the choice over trip duration on multiple objective recreation trips is developed. We explore several methods for allocating trip expenses to estimate the welfare of single and multiple-objective trips. Preliminary results suggest that traditional methods for handling travel costs are inadequate in a multiple-objective setting.Resource /Energy Economics and Policy,

Mapping Topographic Structure in White Matter Pathways with Level Set Trees

Fiber tractography on diffusion imaging data offers rich potential for describing white matter pathways in the human brain, but characterizing the spatial organization in these large and complex data sets remains a challenge. We show that level set trees---which provide a concise representation of the hierarchical mode structure of probability density functions---offer a statistically-principled framework for visualizing and analyzing topography in fiber streamlines. Using diffusion spectrum imaging data collected on neurologically healthy controls (N=30), we mapped white matter pathways from the cortex into the striatum using a deterministic tractography algorithm that estimates fiber bundles as dimensionless streamlines. Level set trees were used for interactive exploration of patterns in the endpoint distributions of the mapped fiber tracks and an efficient segmentation of the tracks that has empirical accuracy comparable to standard nonparametric clustering methods. We show that level set trees can also be generalized to model pseudo-density functions in order to analyze a broader array of data types, including entire fiber streamlines. Finally, resampling methods show the reliability of the level set tree as a descriptive measure of topographic structure, illustrating its potential as a statistical descriptor in brain imaging analysis. These results highlight the broad applicability of level set trees for visualizing and analyzing high-dimensional data like fiber tractography output

Endovascular repair of an actively hemorrhaging gunshot injury to the abdominal aorta

Endovascular stents have had a limited role in the management of trauma and vascular emergencies involving active hemorrhage. We describe a patient with delayed rupture of the infrarenal aorta after intra-abdominal sepsis caused the breakdown of a primary aortic repair. A stent-graft repair was performed, as concomitant injuries did not allow anterior access to the aorta. This report describes the successful endovascular repair of an actively hemorrhaging penetrating abdominal aortic injury. Endovascular approaches to aortic injuries may be valuable in settings where a hostile abdomen precludes traditional open repair

An Emergency Room Decision-Support Program That Increased Physician Office Visits, Decreased Emergency Room Visits, and Saved Money

The objective of this study was to evaluate an Emergency Room having a Decision-Support (ERDS) program designed to appropriately reduce ER use among frequent users, defined as 3 or more visits within a 12-month period. To achieve this, adults with an AARP Medicare Supplement Insurance plan insured by UnitedHealthcare Insurance Company (for New York residents, UnitedHealthcare Insurance Company of New York) were eligible to participate in the program. These included 7070 individuals who elected to enroll in the ERDS program and an equal number of matched nonparticipants who were eligible but either declined or were unreachable. Program-related benefits were estimated by comparing the difference in downstream health care utilization and expenditures between engaged and not engaged individuals after using propensity score matching to adjust for case mix differences between these groups. As a result, compared with the not engaged, engaged individuals experienced better care coordination, evidenced by a greater reduction in ER visits (P=0.033) and hospital admissions (P=0.002) and an increase in office visits (P<0.001). The program was cost-effective, with a return on investment (ROI) of 1.24, which was calculated by dividing the total program savings ($3.41 million) by the total program costs ($2.75 million). The ROI implies that for every dollar invested in this program, $1.24 was saved, most of which was for the federal Medicare program. In conclusion, the decrease in ER visits and hospital admissions and the increase in office visits may indicate the program helped individuals to seek the appropriate levels of care. (Population Health Management 2014;17:257?264)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140184/1/pop.2013.0117.pd

Evaluation of a High-Risk Case Management Pilot Program for Medicare Beneficiaries with Medigap Coverage

The objective was to evaluate the 3-year experience of a high-risk case management (HRCM) pilot program for adults with an AARP Medicare Supplement (Medigap) Insurance Plan. Participants were provided in-person visits as well as telephonic and mailed services to improve care coordination from December 1, 2008, to December 31, 2011. Included were adults who had an AARP Medigap Insurance Plan, resided in 1 of 5 pilot states, and had a Hierarchical Condition Category score>3.74, or were referred into the program. Propensity score weighting was used to adjust for case-mix differences among 2015 participants and 7626 qualified but nonparticipating individuals. Participants were in the program an average of 15.4 months. After weighting, multiple regression analyses were used to estimate differences in quality of care and health care expenditures between participants and nonparticipants. Increased duration in the program was associated with fewer hospital readmissions. Additionally, participants were significantly more likely to have recurring office visits and recommended laboratory tests. The program demonstrated $7.7 million in savings over the 3 years, resulting in a return on investment of$1.40 saved for every dollar spent on the program. Savings increased each year from 2009 to 2011 and with longer length of engagement. The majority of savings were realized by the federal Medicare program. This study focused on quality of care and savings for an HRCM program designed solely for Medicare members with Medicare Supplement coverage. This program had a favorable impact on quality of care and demonstrated savings over a 3-year period. (Population Health Management 2015;18:93?103)Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/140185/1/pop.2014.0035.pd