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

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/cm(2) 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 (K-app) 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 (L-m) from the histology. Although the maximum b value was increased to 80 s/cm(2), the DKI could still describe the nonGaussian diffusion (R-2 > 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. (C) 2016 International Society for Magnetic Resonance in Medicine.