In vivo imaging of the spectral line broadening of the human lung in a single breathhold

Purpose To present a technique, which allows for the in vivo quantification of the spectral line broadening of the human lung in a single breathhold. The line broadening is an interesting parameter of the lung because it can provide information about important lung properties, namely: inflation and oxygen uptake. The proposed technique integrates the asymmetric spin‐echo (ASE) approach, which is commonly used to quantify the line broadening, with a single shot turbo spin‐echo pulse sequence with half‐Fourier acquisition (HASTE), to reduce the acquisition times. Materials and Methods Imaging experiments were performed at 1.5 Tesla on 14 healthy volunteers, using a ASE‐prepared HASTE sequence. The line broadening was quantified using a two‐points method. Data were acquired at different breathing states: functional residual capacity (FRC) and total lung capacity (TLC), and with different breathing gases: room‐air and pure‐oxygen. Image acquisition was accomplished within a single breathhold of approximately 15 s duration. The violation of the Carr‐Purcell‐Meiboom‐Gill conditions, deriving from inhomogeneities of the static magnetic field, was overcome by means of radiofrequency‐phase cycling and generalized autocalibrating partially parallel acquisitions (GRAPPA) reconstruction. Results Significant increase of the line broadening was observed with both lung inflation and oxygen concentration (P