ABSTRACT
RATIONALE AND OBJECTIVES: The ability of motion corrected dynamic 3He-magnetic resonance imaging (MRI) to discriminate distributional patterns of inhaled hyperpolarized 3He between different groups of lung transplant recipients was evaluated. METHODS: An ultrafast low-angle shot 2D sequence (temporal resolution 128 ms) was used for ventilation 3He-MRI of 11 single and 6 double lung transplant recipients. After digital motion correction, signal kinetics were evaluated in a tracheal and 7 pulmonary regions of interest. Results from grafts and native lungs as well as from normal and rejected grafts were compared with each other and to reference values from healthy subjects. RESULTS: In emphysema patients, median alveolar rise time, a parameter for increase of alveolar signal, was 0.28 seconds for the graft and 0.48 seconds for the native lung, in fibrosis patients its median was 0.46 seconds for the graft and 0.21 seconds for the native lung. In double lung recipients, alveolar rise time was 0.29 seconds in normal and clinically rejected grafts. CONCLUSIONS: Dynamic ventilation 3He-MRI discriminated normal lung grafts from diseased native lungs in single lung recipients. Graft rejection in double lung recipients could not be discriminated.
Subject(s)
Helium , Lung Transplantation , Lung/anatomy & histology , Magnetic Resonance Imaging , Ventilation-Perfusion Ratio , Female , Humans , Isotopes , Male , Middle Aged , Motion , Pulmonary Emphysema/pathology , Pulmonary Fibrosis/pathologyABSTRACT
RATIONALE AND OBJECTIVES: Software was developed to correct for lung motion to improve the description of hyperpolarized (3)He gas distribution in the lung. METHODS: Five volunteers were studied by dynamic ventilation (3)He-MRI using an ultrafast FLASH 2D sequence with a temporal resolution of 128 milliseconds. Signal kinetics were evaluated in the trachea and seven parenchymal Regions of Interest. Reference ranges for healthy subjects were defined for motion-corrected and uncorrected images. RESULTS: Motion correction was successfully performed. Reference ranges were 0.11-1.21 seconds for tracheal transit time, 0-0.02 seconds for trachea-alveolar interval, 0.22-0.62 seconds for alveolar rise time and 0-76.6 arbitrary units for alveolar amplitude for motion corrected images, and 0-1.09 seconds, 0-0.11 seconds, 0.26-0.85 seconds, 46.4-99.8 arbitrary units for uncorrected images. CONCLUSIONS: Evaluation of (3)He-distribution in the lung using motion correction of dynamic (3)He-ventilation imaging is feasible and gives more narrow reference ranges.
