Rapid Acquisition of Helium-3 and Proton Three-Dimensional Image Sets of the Human Lung in a Single Breath-Hold Using Compressed Sensing

Purpose: To develop and validate a method for acquiring helium-3 (He-3) and proton (H-1) three-dimensional (3D) image sets of the human lung with isotropic spatial resolution within a 10-s breath-hold by using compressed sensing (CS) acceleration, and to assess the fidelity of undersampled images compared with fully sampled images. Methods: The undersampling scheme for CS acceleration was optimized and tested using He-3 ventilation data. Rapid 3D acquisition of both He-3 and H-1 data during one breath-hold was then implemented, based on a balanced steady-state free-precession pulse sequence, by random undersampling of k-space with reconstruction by means of minimizing the L1 norm and total variance. CS-reconstruction fidelity was evaluated quantitatively by comparing fully sampled and retrospectively undersampled image sets. Results: Helium-3 and H-1 3D image sets of the lung with isotropic 3.9-mm resolution were acquired during a single breath-hold in 12 s and 8 s using acceleration factors of 2 and 3, respectively. Comparison of fully sampled and retrospectively undersampled He-3 and H-1 images yielded mean absolute errors < 10% and structural similarity indices >0.9. Conclusion: By randomly undersampling k-space and using CS reconstruction, high-quality He-3 and H-1 3D image sets with isotropic 3.9-mm resolution can be acquired within an 8-s breath-hold. (C) 2014 Wiley Periodicals, Inc.