Detection of smoke-induced pulmonary lesions by hyperpolarized 129Xe diffusion kurtosis imaging in rat models

Abstract

Purpose: To demonstrate that hyperpolarized (HP) xenon diffusion kurtosis imaging (DKI) is able to detect smoke-induced pulmonary lesions in rat models. Methods: Multi-b DKI with hyperpolarized xenon was used for the first time in five smoke-exposed rats and five healthy rats. Additionally, DKI with b values of up to 80 s/cm2 were used in two healthy rats to probe the critical b value (a limit beyond which the DKI cannot describe the non-Gaussian diffusion). Results: The mean apparent diffusion coefficient (Dapp) and diffusion kurtosis (Kapp) extracted by the DKI model revealed significant changes in the smoke-exposed rats compared with those in the control group (P = 0.027 and 0.039, respectively), exhibiting strong correlations with mean linear intercept (Lm) from the histology. Although the maximum b value was increased to 80 s/cm2, the DKI could still describe the non-Gaussian diffusion (R2 > 0.97). Conclusion: DKI with hyperpolarized xenon exhibited sensitivity in the detection of pulmonary lesions induced by smoke, including moderate emphysema and small airway diseases. The critical b value was rarely exceeded in DKI of the lungs due to the limited gradient strength of the MRI scanner used in our study. Magn Reson Med 78:1891–1899, 2016. © 2016 International Society for Magnetic Resonance in Medicine.