Quantitative MRI measurement of lung density must account for the change in T with lung inflation
Open Access
- 23 July 2009
- journal article
- research article
- Published by Wiley in Journal of Magnetic Resonance Imaging
- Vol. 30 (3), 527-534
- https://doi.org/10.1002/jmri.21866
Abstract
Purpose To evaluate lung water density at three different levels of lung inflation in normal lungs using a fast gradient echo sequence developed for rapid imaging. Materials and Methods Ten healthy volunteers were imaged with a fast gradient echo sequence that collects 12 images alternating between two closely spaced echoes in a single 9‐s breathhold. Data were fit to a single exponential to determine lung water density and T. Data were evaluated in a single imaging slice at total lung capacity (TLC), functional residual capacity (FRC), and residual volume (RV). Analysis of variance for repeated measures was used to statistically evaluate changes in T and lung water density across lung volumes, imaging plane, and spatial locations in the lung. Results In normal subjects (n = 10), T (and [lung density/water density]) was 1.2 ± 0.1 msec (0.10 ± 0.02), 1.8 ± 0.2 ms (0.25 ± 0.04), and 2.0 ± 0.2 msec (0.27 ± 0.03) at TLC, FRC, and RV, respectively. Results also show that there is a considerable intersubject variability in the values of T. Conclusion Data show that T in the lung is very short, and varies considerably with lung volume. Thus, if quantitative assessment of lung density within a breathhold is to be measured accurately, then it is necessary to also determine T. J. Magn. Reson. Imaging 2009.Keywords
This publication has 24 references indexed in Scilit:
- Pulmonary perfusion in the prone and supine postures in the normal human lungJournal of Applied Physiology, 2007
- Vertical gradients in regional lung density and perfusion in the supine human lung: the Slinky effectJournal of Applied Physiology, 2007
- Measurement of MR signal and T2* in lung to characterize a tight skin mouse model of emphysema using single-point imagingJournal of Magnetic Resonance Imaging, 2007
- Steep head-down tilt has persisting effects on the distribution of pulmonary blood flowJournal of Applied Physiology, 2006
- Distribution of regional density and vascular permeability in the adult respiratory distress syndrome.American Journal of Respiratory and Critical Care Medicine, 1995
- Measurement of Lung Water Content and Pleural Pressure Gradient with Magnetic Resonance ImagingJournal of Thoracic Imaging, 1995
- An in vivo NMR imaging determination of multiexponential Hahn T2 of normal lungMagnetic Resonance in Medicine, 1990
- A comparison of fast spin echo and gradient field echo sequencesMagnetic Resonance Imaging, 1988
- Effect of Changes in Inflation and Blood Volume on Regional Lung Density—A PET StudyJournal of Computer Assisted Tomography, 1986
- PET Measurement of Regional Lung DensityJournal of Computer Assisted Tomography, 1986