NEMA NU 2-2007 performance characteristics of GE Signa integrated PET/MR for different PET isotopes

BackgroundFully integrated PET/MR systems are being used frequently in clinical research and routine. National Electrical Manufacturers Association (NEMA) characterization of these systems is generally done with F-18 which is clinically the most relevant PET isotope. However, other PET isotopes, such as Ga-68 and Y-90, are gaining clinical importance as they are of specific interest for oncological applications and for follow-up of Y-90-based radionuclide therapy. These isotopes have a complex decay scheme with a variety of prompt gammas in coincidence. Ga-68 and Y-90 have higher positron energy and, because of the larger positron range, there may be interference with the magnetic field of the MR compared to F-18. Therefore, it is relevant to determine the performance of PET/MR for these clinically relevant and commercially available isotopes.MethodsNEMA NU 2-2007 performance measurements were performed for characterizing the spatial resolution, sensitivity, image quality, and the accuracy of attenuation and scatter corrections for F-18, Ga-68, and Y-90. Scatter fraction and noise equivalent count rate (NECR) tests were performed using F-18 and Ga-68. All phantom data were acquired on the GE Signa integrated PET/MR system, installed in UZ Leuven, Belgium.Results(18)F, Ga-68, and Y-90 NEMA performance tests resulted in substantially different system characteristics. In comparison with F-18, the spatial resolution is about 1mm larger in the axial direction for Ga-68 and no significative effect was found for Y-90. The impact of this lower resolution is also visible in the recovery coefficients of the smallest spheres of Ga-68 in image quality measurements, where clearly lower values are obtained. For Y-90, the low number of counts leads to a large variability in the image quality measurements. The primary factor for the sensitivity change is the scale factor related to the positron emission fraction. There is also an impact on the peak NECR, which is lower for Ga-68 than for F-18 and appears at higher activities.ConclusionsThe system performance of GE Signa integrated PET/MR was substantially different, in terms of NEMA spatial resolution, image quality, and NECR for Ga-68 and Y-90 compared to F-18. But these differences are compensated by the PET/MR scanner technologies and reconstructions methods

Pilot Interprofessional Education Program for OT Student Pediatric Practice Readiness

This mixed methods pilot study investigated the impact of an interprofessional education program on OT student readiness for collaboration with SLP students in a pediatric teaching-clinic practice setting. OT students were randomly assigned to either the treatment group, which received the interprofessional education experience, or the control group, which received the typical educational experience. Students completed pre and post surveys and journaled about the experience. Results pointed to a ceiling effect in the measurement scales in both the treatment and control groups due to positive attitudes at baseline. This positivity was also reflected in journal entries for the treatment group students. Several insights were gained through data analysis about the feasibility of this type of program, the usefulness of available measuring tools for detecting change in small samples, and the developmental progression of interprofessional skills attainment

Clinical outcomes after first-line HIV treatment failure in South Africa: the next cascade of care

Introduction There is limited literature on the appropriateness of viral load (VL) monitoring and management of detectable VL in public health settings in rural South Africa. Methods We analysed data captured in the electronic patient register from HIV‐positive patients ≥ 15 years old initiating antiretroviral therapy (ART) in 17 public sector clinics in rural KwaZulu‐Natal, during 2010–2016. We estimated the completion rate for VL monitoring at 6, 12, and 24 months. We described the cascade of care for those with any VL measurement ≥ 1000 HIV‐1 RNA copies/mL after ≥ 20 weeks on ART, including the following proportions: (1) repeat VL within 6 months; (2) re‐suppressed; (3) switched to second‐line regimen. Results There were 29 384 individuals who initiated ART during the period [69% female, median age 31 years (interquartile range 25–39)]. Of those in care at 6, 12, and 24 months, 40.7% (9861/24 199), 34% (7765/22 807), and 25.5% (4334/16 965) had a VL test at each recommended time‐point, respectively. The VL results were documented at all recommended time‐points for 12% (2730/22 807) and 6.2% (1054/16 965) of ART‐treated patients for 12 and 24 months, respectively. Only 391 (18.3%) of 2135 individuals with VL ≥ 1000 copies/mL on first‐line ART had a repeat VL documenting re‐suppression or were appropriately changed to second‐line with persistent failure. Completion of the treatment failure cascade occurred a median of 338 days after failure was detected. Conclusion We found suboptimal VL monitoring and poor responses to virologic failure in public‐sector ART clinics in rural South Arica. Implications include increased likelihood of morbidity and transmission of drug‐resistant HIV

Does antiretroviral therapy use affect the accuracy of HIV rapid diagnostic assays? Experience from a demographic health and surveillance site in rural South Africa

Rapid diagnostic tests (RDTs) are the mainstay of HIV diagnosis in the developing world but might have poor sensitivity among individuals taking antiretroviral therapy (ART). We leveraged a home-based HIV testing program linked to clinical data to compare the sensitivity of RDTs between individuals using versus not using ART. Field workers tested 6802 individuals using 2 HIV RDTs, which were compared to a single HIV immunoassay tested on dried blood spots. Approximately 5% (371/6802) tested positive by immunoassay, of whom 157 (42%) were currently on ART. The sensitivity of the Abon RDT among those never versus currently on ART was 91.6% (95% CI 88.3–94.3) and 96.6% (95% CI 88.3–94.3), respectively, and 95.4% (95% CI 92.8–97.3) versus 99.3% (95% CI 95.2–99.7) for the Advanced Quality assay. We report similar sensitivity of RDTs in ART-naïve and ART-experienced individuals, which mitigates concerns about their use among treated individuals in population-based epidemiologic surveys and those transferring care

Does antiretroviral treatment increase the infectiousness of smear-positive pulmonary tuberculosis?

BACKGROUND: Understanding of the effects of human immunodeficiency virus (HIV) infection and antiretroviral treatment (ART) on Mycobacterium tuberculosis transmission dynamics remains limited. We undertook a cross-sectional study among household contacts of smear-positive pulmonary tuberculosis (TB) cases to assess the effect of established ART on the infectiousness of TB. METHOD: Prevalence of tuberculin skin test (TST) positivity was compared between contacts of index cases aged 2-10 years who were HIV-negative, HIV-positive but not on ART, on ART for <1 year and on ART for 1 year. Random-effects logistic regression was used to take into account clustering within households. RESULTS: Prevalence of M. tuberculosis infection in contacts of HIV-negative patients, HIV-positive patients on ART 1 year and HIV-positive patients not on ART/on ART <1 year index cases was respectively 44%, 21% and 22%. Compared to contacts of HIV-positive index cases not on ART or recently started on ART, the odds of TST positivity was similar in contacts of HIV-positive index cases on ART 1 year (adjusted OR [aOR] 1.0, 95%CI 0.3-3.7). The odds were 2.9 times higher in child contacts of HIV-negative index cases (aOR 2.9, 95%CI 1.0-8.2). CONCLUSIONS: We found no evidence that established ART increased the infectiousness of smear-positive, HIV-positive index cases

The path of ambivalence: tracing the pull of opposing evaluations using mouse trajectories

Ambivalence refers to a psychological conflict between opposing evaluations, often experienced as being torn between alternatives. This dynamic aspect of ambivalence is hard to capture with outcome-focused measures, such as response times or self-report. To gain more insight into ambivalence as it unfolds, the current work uses an embodied measure of pull, drawing on research in dynamic systems. In three studies, using different materials, we tracked people’s mouse movements as they chose between negative and positive evaluations of attitude objects. When participants evaluated ambivalent attitude objects, their mouse trajectories showed more pull of the non-chosen evaluative option than when they evaluated univalent attitude objects, revealing that participants were literally torn between the two opposing evaluations. We address the relationship of this dynamic measure to response time and self-reports of ambivalence and discuss implications and avenues for future research

The Euro Diffusion Project

From 1st January 2002 we have the unique possibility to follow the spread of national euro coins over the different European countries. We model and analyse this movement and estimate the time it will take before on average half the coins in our wallet will be foreign

Risk factors for Mycobacterium tuberculosis infection in 2-4 year olds in a rural HIV-prevalent setting.

BACKGROUND: Mycobacterium tuberculosis infection in children acts as a sentinel for infectious tuberculosis. OBJECTIVE: To assess risk factors associated with tuberculous infection in pre-school children. METHOD: We conducted a population-wide tuberculin skin test (TST) survey from January to December 2012 in Malawi. All children aged 2-4 years residing in a demographic surveillance area were eligible. Detailed demographic data, including adult human immunodeficiency virus (HIV) status, and clinical and sociodemographic data on all diagnosed tuberculosis (TB) patients were available. RESULTS: The prevalence of M. tuberculosis infection was 1.1% using a TST induration cut-off of 15 mm (estimated annual risk of infection of 0.3%). The main identifiable risk factors were maternal HIV infection at birth (adjusted OR [aOR] 3.6, 95%CI 1.1-12.2), having three or more adult members in the household over a lifetime (aOR 2.4, 95%CI 1.2-4.8) and living in close proximity to a known case of infectious TB (aOR 1.6, 95%CI 1.1-2.4), modelled as a linear variable across categories (>200 m, 100-200 m, <100 m, within household). Less than 20% of the infected children lived within 200 m of a known diagnosed case. CONCLUSION: Household and community risk factors identified do not explain the majority of M. tuberculosis infections in children in our setting