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Background The prevalence of pediatric allergic diseases has increased rapidly in the United States over the past few decades. Recent studies suggest an association between the increase in allergic disease and early disturbances to the gut microbiome. The gut microbiome is a set of intestinal microorganisms that begins to form during birth and is highly susceptible to disturbance during the first year of life. Early antibiotic exposure may negatively impact the gut microbiota by altering the bacterial composition and causing dysbiosis, thus increasing the risk for developing childhood allergic disease. Methods We performed a retrospective chart review of data in Loyola University Medical Center’s (LUMC) Epic system from 2007 to 2016. We defined antibiotic exposure as orders in both the outpatient and inpatient settings. Inclusion criteria were being born at LUMC with at least two follow up visits. Asthma and allergic rhinitis diagnoses were obtained using ICD 9 and ICD 10 codes. We controlled for multiple confounding factors. Using Stata, bivariate logistic regression was performed between antibiotics from 0 to 12 months of life and development of disease. This analysis was repeated for total lifetime antibiotics. We defined statistically significant as p < .05. Results The administration of antibiotics within the first 12 months of life was significantly associated with lifetime asthma (OR 2.66; C. I 1.11–6.40) but not allergic rhinitis. There was a significant association between lifetime antibiotics and asthma (OR 3.54; C. I 1.99–6.30) and allergic rhinitis (OR 2.43; C. I 1.43–4.11). Conclusion Antibiotic administration in the first year of life and throughout lifetime is significantly associated with developing asthma and allergic rhinitis. These results provide support for a conservative approach regarding antibiotic use in early childhood.

Purpose:To test the hypothesis that fractional kidney hypoxia, measured by using blood oxygen level-dependent (BOLD) magnetic resonance (MR) imaging, correlates with renal blood flow (RBF), tissue perfusion, and glomerular filtration rate (GFR) in patients with atherosclerotic renal artery stenosis (RAS) better than regionally selected region of interest-based methods. Materials and Methods:The study was approved by the institutional review board according to a HIPAA-compliant protocol, with written informed consent. BOLD MR imaging was performed in 40 patients with atherosclerotic RAS (age range, 51-83 years; 22 men, 18 women) and 32 patients with essential hypertension (EH) (age range, 26-85 years; 19 men, 13 women) during sodium intake and renin-angiotensin blockade. Fractional kidney hypoxia (percentage of entire axial image section with R2* above 30 sec 21) and conventional regional estimates of cortical and medullary R2* levels were measured. Stenotic and nonstenotic contralateral kidneys were compared for volume, tissue perfusion, and blood flow measured with multidetector computed tomography. Statistical analysis was performed (paired and nonpaired t tests, linear regression analysis). Results:Stenotic RBF was reduced compared with RBF of contralateral kidneys (225.2 mL/min vs 348 mL/min, P = .0003). Medullary perfusion in atherosclerotic RAS patients was lower than in EH patients (1.07 mL/min per milliliter of tissue vs 1.3 mL/min per milliliter of tissue, P = .009). While observer-selected cortical R2* (18.9 sec 21 [stenosis] vs 18.5 sec 21 [EH], P = .07) did not differ, fractional kidney hypoxia was higher in stenotic kidneys compared with kidneys with EH (17.4% vs 9.6%, P , .0001) and contralateral kidneys (7.2%, P , .0001). Fractional hypoxia correlated inversely with blood flow (r = 20.34), perfusion (r = 20.3), and GFR (r = 20.32). Conclusion:Fractional tissue hypoxia rather than cortical or medullary R2* values used to assess renal BOLD MR imaging demonstrated a direct relationship to chronically reduced blood flow and GFR.q RSNA, 2013 Supplemental material: http://radiology.rsna.org/lookup /suppl

With a strong clinical indication and with careful monitoring, MRI imaging is feasible in patients with recently implanted pacemakers, although experience is limited.