Ferumoxytol-enhanced magnetic resonance imaging methodology and normal values at 1.5 and 3T

Background: ultrasmall superparamagnetic particles of iron oxide (uspio)-enhanced magnetic resonance imaging (mri) can detect tissue-resident macrophage activity and identify cellular inflammation. clinical studies using this technique are now emerging. we aimed to report a range of normal r2∗values at 1.5 and 3 t in the myocardium and other tissues following ferumoxytol administration,outline the methodology used and suggest solutions to commonly encountered analysis problems. methods: twenty volunteers were recruited: 10 imaged each at 1.5 t and 3 t. t2∗and late gadolinium enhanced (lge) mri was conducted at baseline with further t2∗imaging conducted approximately 24 h after uspio infusion (ferumoxytol,4 mg/kg). regions of interest were selected in the myocardium and compared to other tissues. results: following administration,uspio was detected by changes in r2∗from baseline (1/t2∗) at 24 h in myocardium,skeletal muscle,kidney,liver,spleen and blood at 1.5 t,and myocardium,kidney,liver,spleen,blood and bone at 3 t (p < 0.05 for all). myocardial changes in r2∗due to uspio were 26.5 ± 7.3 s-1 at 1.5 t,and 37.2 ± 9.6 s-1 at 3 t (p < 0.0001 for both). tissues showing greatest ferumoxytol enhancement were the reticuloendothelial system: the liver,spleen and bone marrow (216.3 ± 32.6 s-1,336.3 ± 60.3 s-1,69.9 ± 79.9 s-1; p < 0.0001,p < 0.0001,p = ns respectively at 1.5 t,and 275.6 ± 69.9 s-1,463.9 ± 136.7 s-1,417.9 ± 370.3 s-1; p < 0.0001,p < 0.0001,p < 0.01 respectively at 3 t). conclusion: ferumoxytol-enhanced mri is feasible at both 1.5 t and 3 t. careful data selection and dose administration,along with refinements to echo-time acquisition,post-processing and analysis techniques are essential to ensure reliable and robust quantification of tissue enhancement. trial registration: clinicaltrials.gov identifier - nct02319278. registered 03.12.2014. © 2016 the author(s).