Moabi, Kebaiphe

ABSTRACT The lower infrastructure requirements of portable ultra‐low field MRI (ULF‐MRI) systems have enabled their use in diverse settings such as intensive care units and remote medical facilities. The UNITY Project is an international neuroimaging network harnessing this technology, deploying portable ULF‐MRI systems globally to expand access to MRI for studies into brain development. Given the wide range of environments where ULF‐MRI systems may operate, there are external factors that might influence image quality. This work aims to introduce the quality control (QC) framework used by the UNITY Project to investigate how robust the systems are and how QC metrics compare between sites and over time. We present a QC framework using a commercially available phantom, scanned with 64 mT portable MRI systems at 17 sites across 12 countries on four continents. Using automated, open‐source analysis tools, we quantify signal‐to‐noise, image contrast, and geometric distortions. Our results demonstrated that the image quality is robust to the varying operational environment, for example, electromagnetic noise interference and temperature. The Larmor frequency was significantly correlated to room temperature, as was image noise and contrast. Image distortions were less than 2.5 mm, with high robustness over time. Similar to studies at higher field, we found that changes in pulse sequence parameters from software updates had an impact on QC metrics. This study demonstrates that portable ULF‐MRI systems can be deployed in a variety of environments for multi‐center neuroimaging studies and produce robust results.

Objective: To examine the impact of in-utero exposure to dolutegravir (DTG)-based or efavirenz (EFV)-based antiretroviral treatment (ART) on child neurodevelopmental outcomes. Design: Prospective cohort design, enrolling three cohorts of 2-year-olds: children HIV-negative born to mothers with HIV (CHEU) receiving either DTG-based or EFV-based three-drug ART during pregnancy, and children born to mothers without HIV (CHUU). Methods: Primary child neurodevelopmental outcomes were assessed using the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) and compared between cohorts using generalized estimating equation models adjusted for confounders. Children were classified as having an ‘adverse ND outcome’ if they scored at least 1 standard deviation (SD) below the mean or were unable to complete the BSID-III. Results: Five hundred and sixty-four participants (202 DTG-exposed, 202 EFV-exposed, 160 HIV-unexposed; mean age 25.7 months, 49% female). Mean (SD) Gross Motor scores were slightly lower among CHEU vs. CHUU [54.6 (3.6) vs. 55.6 (4.3)] and among EFV-exposed vs. DTG-exposed [54.3 (3.5) vs. 54.9 (3.6)]. CHEU were more likely to be classified as having an ‘adverse’ expressive language outcome [13.2 vs 7%, adjusted risk ratio (aRR) = 2.06, 95% confidence interval (CI) 1.05–4.03] than CHUU, but other neurodevelopmental outcomes were similar. DTG exposure was associated with less frequent ‘adverse’ classification in Cognitive (2.5 vs. 7.4%, aRR = 0.33, 95% CI 0.13–0.79) and Expressive Language domains (10.0 vs. 16.4%, aRR = 0.58, 95% CI 0.35, 0.95), compared to EFV exposure. Conclusion: Two-year neurodevelopmental outcomes among Botswana children DTG-exposed, EFV-exposed, and HIV-unexposed were mostly comparable. Children exposed in utero to EFV-based ART had higher risk of ‘adverse’ cognitive and expressive language outcomes compared with children DTG-exposed.