Characterization of R 2 ∗ and tissue density in the human lung: Application to neonatal imaging in the intensive care unit.

Estimation of tissue density and R 2 ∗ in free breathing, nonsedated, neonatal patients is feasible using multiecho ultrashort echo time MRI. R 2 ∗ was no different between infants and adults when matched for tissue density, although density of lung parenchyma was, on average, lower in adults than neonates.