The first step for neuroimaging data analysis: DICOM to NIfTI conversion

BACKGROUND: Clinical imaging data are typically stored and transferred in the DICOM format, whereas the NIfTI format has been widely adopted by scientists in the neuroimaging community. Therefore, a vital initial step in processing the data is to convert images from the complicated DICOM format to the much simpler NIfTI format. While there are a number of tools that usually handle DICOM to NIfTI conversion seamlessly, some variations can disrupt this process. NEW METHOD: We provide some insight into the challenges faced with image conversion. First, different manufacturers implement the DICOM format differently which complicates the conversion. Second, different modalities and sub-modalities may need special treatment during conversion. Lastly, the image transferring and archiving can also impact the DICOM conversion. RESULTS: We present results in several error-prone domains, including the slice order for functional imaging, phase encoding direction for distortion correction, effect of diffusion gradient direction, and effect of gantry correction for some imaging modality. COMPARISON WITH EXISTING METHODS: Conversion tools are often designed for a specific manufacturer or modality. The tools and insight we present here are aimed at different manufacturers or modalities. CONCLUSIONS: The imaging conversion is complicated by the variation of images. An understanding of the conversion basics can be helpful for identifying the source of the error. Here we provide users with simple methods for detecting and correcting problems. This also serves as an overview for developers who wish to either develop their own tools or adapt the open source tools created by the authors

Brain activation in response to personalized behavioral and physiological feedback from self-monitoring technology: pilot study

Background: The recent surge in commercially available wearable technology has allowed real-time self-monitoring of behavior (eg, physical activity) and physiology (eg, glucose levels). However, there is limited neuroimaging work (ie, functional magnetic resonance imaging [fMRI]) to identify how people’s brains respond to receiving this personalized health feedback and how this impacts subsequent behavior. Objective: Identify regions of the brain activated and examine associations between activation and behavior. Methods: This was a pilot study to assess physical activity, sedentary time, and glucose levels over 14 days in 33 adults (aged 30 to 60 years). Extracted accelerometry, inclinometry, and interstitial glucose data informed the construction of personalized feedback messages (eg, average number of steps per day). These messages were subsequently presented visually to participants during fMRI. Participant physical activity levels and sedentary time were assessed again for 8 days following exposure to this personalized feedback. Results: Independent tests identified significant activations within the prefrontal cortex in response to glucose feedback compared with behavioral feedback (P<.001). Reductions in mean sedentary time (589.0 vs 560.0 minutes per day, P=.014) were observed. Activation in the subgyral area had a moderate correlation with minutes of moderate-to-vigorous physical activity (r=0.392, P=.043). Conclusion: Presenting personalized glucose feedback resulted in significantly more brain activation when compared with behavior. Participants reduced time spent sedentary at follow-up. Research on deploying behavioral and physiological feedback warrants further investigation

Metadata correction: Brain activation in response to personalized behavioral and physiological feedback from self-monitoring technology: pilot study

[This corrects the article DOI: 10.2196/jmir.8890.]

HYDROGEN EFFECTS ON STRAIN-INDUCED MARTENSITE FORMATION IN TYPE 304L STAINLESS STEEL

Unstable austenitic stainless steels undergo a strain-induced martensite transformation. The effect of hydrogen on this transformation is not well understood. Some researchers believe that hydrogen makes the transformation to martensite more difficult because hydrogen is an austenite stabilizer. Others believe that hydrogen has little or no effect at all on the transformation and claim that the transformation is simply a function of strain and temperature. Still other researchers believe that hydrogen should increase the ability of the metal to transform due to hydrogen-enhanced dislocation mobility and slip planarity. While the role of hydrogen on the martensite transformation is still debated, it has been experimentally verified that this transformation does occur in hydrogen-charged materials. What is the effect of strain-induced martensite on hydrogen embrittlement? Martensite near crack-tips or other highly strained regions could provide much higher hydrogen diffusivity and allow for quicker hydrogen concentration. Martensite may be more intrinsically brittle than austenite and has been shown to be severely embrittled by hydrogen. However, it does not appear to be a necessary condition for embrittlement since Type 21-6-9 stainless steel is more stable than Type 304L stainless steel but susceptible to hydrogen embrittlement. In this study, the effect of hydrogen on strain-induced martensite formation in Type 304L stainless steel was investigated by monitoring the formation of martensite during tensile tests of as-received and hydrogen-charged samples and metallographically examining specimens from interrupted tensile tests after increasing levels of strain. The effect of hydrogen on the fracture mechanisms was also studied by examining the fracture features of as-received and hydrogen-charged specimens and relating them to the stress-strain behavior

Satellite cells derived from the mdx murine model of Duchenne muscular dystrophy retain their muscle regenerative capacity

Duchenne muscular dystrophy is an inherited disorder that is characterized by progressive skeletal muscle weakness and wasting, with a failure of muscle maintenance/repair mediated by satellite cells (muscle stem cells). The function of skeletal muscle stem cells resident in dystrophic muscle may be perturbed by being in an increasing pathological environment, coupled with constant demands for repairing muscle. To investigate the contribution of satellite cell exhaustion to this process, we tested the functionality of satellite cells isolated from the mdx mouse model of Duchenne muscular dystrophy. We found that satellite cells derived from young mdx mice contributed efficiently to muscle regeneration within our in vivo mouse model. To then test the effects of long-term residence in a dystrophic environment, satellite cells were isolated from aged mdx muscle. Surprisingly, they were as functional as those derived from young or aged wild type donors. Removing satellite cells from a dystrophic milieu reveals that their regenerative capacity remains both intact and similar to satellite cells derived from healthy muscle, indicating that the host environment is critical for mediating efficient satellite cell function

Online Obsessive-Compulsive Disorder Treatment: Preliminary Results of the "OCD? Not Me!" Self-Guided Internet-Based Cognitive Behavioral Therapy Program for Young People

BACKGROUND: The development and evaluation of Internet-delivered cognitive behavioral therapy (iCBT) interventions provides a potential solution for current limitations in the acceptability, availability, and accessibility of mental health care for young people with obsessive-compulsive disorder (OCD). Preliminary results support the effectiveness of therapist-assisted iCBT for young people with OCD; however, no previous studies have examined the effectiveness of completely self-guided iCBT for OCD in young people. OBJECTIVE: We aimed to conduct a preliminary evaluation of the effectiveness of the OCD? Not Me! program for reducing OCD-related psychopathology in young people (12-18 years). This program is an eight-stage, completely self-guided iCBT treatment for OCD, which is based on exposure and response prevention. METHODS: These data were early and preliminary results of a longer study in which an open trial design is being used to evaluate the effectiveness of the OCD? Not Me! PROGRAM: Participants were required to have at least subclinical levels of OCD to be offered the online program. Participants with moderate-high suicide/self-harm risk or symptoms of eating disorder or psychosis were not offered the program. OCD symptoms and severity were measured at pre- and posttest, and at the beginning of each stage of the program. Data was analyzed using generalized linear mixed models. RESULTS: A total of 334 people were screened for inclusion in the study, with 132 participants aged 12 to 18 years providing data for the final analysis. Participants showed significant reductions in OCD symptoms (P&lt;.001) and severity (P&lt;.001) between pre- and posttest. CONCLUSIONS: These preliminary results suggest that fully automated iCBT holds promise as a way of increasing access to treatment for young people with OCD; however, further research needs to be conducted to replicate the results and to determine the feasibility of the program. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR): ACTRN12613000152729; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=363654 (Archived by WebCite at http://www.webcitation.org/ 6iD7EDFqH)

HYDROGEN EFFECTS ON THE BURST PROPERTIES OF TYPE 304L STAINLESS STEEL FLAWED VESSELS

The effect of hydrogen on the burst properties Type 304L stainless steel vessels was investigated. The purpose of the study was to compare the burst properties of hydrogen-exposed stainless steel vessels burst with different media: water, helium gas, or deuterium gas. A second purpose of the tests was to provide data for the development of a predictive finite-element model. The burst tests were conducted on hydrogen-exposed and unexposed axially-flawed cylindrical vessels. The results indicate that samples burst pneumatically had lower volume ductility than those tested hydraulically. Deuterium gas tests had slightly lower ductility than helium gas tests. Burst pressures were not affected by burst media. Hydrogen-charged samples had lower volume ductility and slightly higher burst pressures than uncharged samples. Samples burst with deuterium gas fractured by quasi-cleavage near the inside wall. The results of the tests were used to improve a previously developed predictive finite-element model. The results show that predicting burst behavior requires as a material input the effect of hydrogen on the plastic strain to fracture from tensile tests. The burst test model shows that a reduction in the plastic strain to fracture of the material will result in lower volume ductility without a reduction in burst pressure which is in agreement with the burst results

Why does the provision of home mechanical ventilation vary so widely?

There is wide variation in the provision of home mechanical ventilation (HMV) throughout Europe, but the provision of home mechanical ventilation can also vary within countries. In 2008, the overall prevalence of HMV in Norway was 19.9/100,000, and there were huge regional differences in treatment prevalence. The aim of this study is to find explanations for these differences. We gathered multidisciplinary respondents involved in HMV treatment from five hospitals in five different counties to six focus group conversations to explore respondents' views of their experiences systematically. We based the analysis on grounded theory. We found that uneven distribution of “enthusiasm” between hospitals seems to be an important factor in the geographical distribution of HMV. Furthermore, we found that the three subcategories, “high competence,” “spreading competence,” and “multidisciplinary collaboration,” are developed and used systematically in counties with “enthusiasm.” This culture is the main category, which might explain the differences, and is described as “wise enthusiasm.” The last subcategory is “individual attitudes” about HMV among decision-making physicians. The most important factor is most likely the uneven distribution of highly skilled enthusiasm between hospitals. Individual attitudes about HMV among the decision makers may also explain why the provision of HMV varies so widely. Data describing regional differences in the prevalence of HMV within countries is lacking. Further research is needed to identify these differences to ensure equality of provision of HMV