Detection of smoke-induced pulmonary lesions by hyperpolarized 129 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/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.