Hyperpolarized 129Xe dynamic study in mouse lung under spontaneous respiration: Application to murine tumor B16BL6 melanoma

This is a study on the analysis of hyperpolarized (HP) 129Xe dynamics applied in the lung of a pathological model mouse under spontaneous respiration. A novel parameter k1k2 - a product of the rate constant for Xe transfer from gas to dissolved phase (k1) and from dissolved to gas phase (k2) - was shown to be derived successfully from the analysis of the HP 129Xe dynamic MR experiment in the mouse lung under spontaneous respiration with the aid of a selective pre-saturation technique. A comparative study using healthy mice and model mice induced with lung cancer (by injection of murine tumor B16BL6 melanoma) was performed and a significant difference was found in the k1k2 values of the two groups, that is, 0.020 ± 0.007 s−2 (n = 4) for healthy mice and 0.032 ± 0.04 s−2 (n = 3) for lung cancer model mice (p = 0.04). Thus, the parameter obtained by our proposed method is considered useful for detection of lung tumors.