Effect of respiratory phases on MR lung signal intensity and lung conspicuity using segmented multiple inversion recovery turbo spin echo (MIR-TSE)

The purpose of this study was to determine the effect of respiratory phase on signal intensity of the lung. Lung images were obtained from eleven healthy human volunteers using a multiple inversion recovery segmented turbo spin echo sequence (MIR-TSE). MIR exploits the difference in T-1 between different tissues to effectively null signal contributions from fat and muscle for improved visualization of the lung. The volunteers were asked to perform breath-holding on end inspiration or end expiration. There was a significant decrease in signal intensity of the lung with average SNR of 7.3 +/- 0.9 vs. 14.4 +/- 0.8 for coronal slices, and 9.5 +/- 1.5 vs. 16.0 +/- 2.4 for sagittal breath-hold images acquired during end inspiration compared with end expiration. It is concluded that MRI of the lungs should be performed during end expiration in order to optimize image quality. Magn Reson Med 43: 760-763, 2000. (C) 2000 Wiley-Liss, Inc.