Investigative radiology
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Investigative radiology · Jun 2008
Magnetic resonance imaging of lung tissue: influence of body positioning, breathing and oxygen inhalation on signal decay using multi-echo gradient-echo sequences.
To assess susceptibility related signal decay in lung tissue and to measure the influence of body positioning, together with inspiration and expiration, as well as oxygen inhalation. T2* maps and line shape maps of lung parenchyma were derived from datasets acquired at 0.2 T and compared with findings at 1.5 T. The line shape maps allow for a visualization of the intravoxel frequency distribution of lung parenchyma. ⋯ The proposed method allows for the computation of color-encoded T2* maps and FWHM maps of lung parenchyma in good image quality using datasets acquired at 0.2 T. The technique is robust and sensitive to physiological changes of lung magnetic resonance properties, eg, due to the type of body positioning or oxygen breathing.
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Investigative radiology · Jun 2008
Quantification of lung volume at different tidal volumes and positive end-expiratory pressures in a porcine model by using retrospective respiratory gated 4D-computed tomography.
This feasibility study in healthy animals should prove the concept that it is possible to quantitatively assess the effects of different ventilatory settings on the lung parenchyma during ongoing ventilation in respiratory gated 4-dimensional (D)-computed tomography (CT). For this purpose, the influence of different tidal volumes and positive end-expiratory pressure (PEEP) on quantitative assessment of lung volumes (LVs) and lung compartments was analyzed. ⋯ Using a new 4D-CT technique we were able to demonstrate the effect of different ventilation settings on the whole lung during the whole respiratory cycle. The disadvantages of static lung imaging or dynamic 2D-CT can be overcome. The possibility of quantitative evaluation of the whole lung and direct visualization and measurement of recruitment during different ventilation settings might be a great benefit for patients suffering from inhomogeneous lung injury and failure.