Comparison of hyperpolarized 3He and 129Xe MRI for the measurement of absolute ventilated lung volume in rats

Abstract

Purpose MRI using hyperpolarized noble gases, 3He and 129Xe, provides noninvasive assessments of lung structure and function. Previous work demonstrated that absolute ventilated lung volumes (aVLV) measured in rats using hyperpolarized 3He agree well with micro-CT. Methods In this work, aVLV measurements were performed in rats using hyperpolarized 129Xe MRI and compared with hyperpolarized 3He measurements of aVLV under matched ventilation conditions. Whole-lung compliance was also determined. Partial volume, apparent diffusion coefficient, and effective transverse relaxation time corrections were applied during postprocessing to reduce bias between methods. Results Mean apparent diffusion coefficient of the trachea was 0.83 ± 0.09 cm2/s and 0.067 ± 0.011 cm2/s for 3He and 129Xe, respectively. Mean apparent diffusion coefficient of parenchyma was 0.21 ± 0.07 cm2/s and 0.027 ± 0.008 cm2/s for 3He and 129Xe, respectively. Mean transverse relaxation time values were 1.57 ± 0.25 ms and 2.80 ± 0.25 ms for 3He and 129Xe, respectively, in a model trachea and 3.18 ± 1.00 ms and 4.88 ± 0.60 ms for 3He and 129Xe, respectively, for lung parenchyma. Mean aVLV values were 7.07 ± 0.67 mL and 6.99 ± 1.00 mL at 14 cmH2O and 4.88 ± 0.71 mL and 5.36 ± 0.76 mL at 10 cmH2O obtained with 3He and 129Xe, respectively, demonstrating good agreement between 129Xe and 3He. Conclusions 129Xe offers an important alternative to 3He for hyperpolarized gas MRI of aVLV in rats. © 2013 Wiley Periodicals, Inc.