Comparison of Hyperpolarized 3He and 129Xe MRI for the Measurement of Absolute Ventilated Lung Volume in Rats

PurposeMRI using hyperpolarized noble gases, He-3 and Xe-129, provides noninvasive assessments of lung structure and function. Previous work demonstrated that absolute ventilated lung volumes (aVLV) measured in rats using hyperpolarized He-3 agree well with micro-CT. MethodsIn this work, aVLV measurements were performed in rats using hyperpolarized Xe-129 MRI and compared with hyperpolarized He-3 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. ResultsMean apparent diffusion coefficient of the trachea was 0.830.09 cm(2)/s and 0.067 +/- 0.011 cm(2)/s for He-3 and Xe-129, respectively. Mean apparent diffusion coefficient of parenchyma was 0.21 +/- 0.07 cm(2)/s and 0.027 +/- 0.008 cm(2)/s for He-3 and Xe-129, respectively. Mean transverse relaxation time values were 1.57 +/- 0.25 ms and 2.80 +/- 0.25 ms for He-3 and Xe-129, respectively, in a model trachea and 3.18 +/- 1.00 ms and 4.88 +/- 0.60 ms for He-3 and Xe-129, respectively, for lung parenchyma. Mean aVLV values were 7.07 +/- 0.67 mL and 6.99 +/- 1.00 mL at 14 cmH(2)O and 4.88 +/- 0.71 mL and 5.36 +/- 0.76 mL at 10 cmH(2)O obtained with He-3 and Xe-129, respectively, demonstrating good agreement between Xe-129 and He-3. Conclusions(129)Xe offers an important alternative to He-3 for hyperpolarized gas MRI of aVLV in rats. Magn Reson Med 71:1130-1136, 2014. (c) 2013 Wiley Periodicals, Inc.