Measurement of pulmonary hematocrit using oscillation of hyperpolarized 129Xe MR signals in blood

Purpose: To demonstrate the feasibility of measuring pulmonary hematocrit (Hct) in blood in vivo using oscillation of hyperpolarized 129Xe MR signals and its potential for disease assessment in animal models.
Methods: Hyperpolarized 129Xe dynamic MR spectroscopy was performed on 10 anemia model rats and 10 control rats. A concisemodel based on hyperpolarized 129XeMR signal oscillations was built for calculating pulmonary Hct. Blood tests and chemical shift saturation recoverywere conducted on each rat to obtain Hct. Correlations of Hct obtained from different methods were analyzed using SPSS 22.0.
Results: Hctmeasurements were strongly correlated with blood test (Spearman correlation coefficient r =0.871, p<0.001) and chemical shift saturation recovery measurements (r =0.956, p<0.001). Hct was 0.198±0.054 for the anemic cohort and 0.457±0.039 for the control group (p<0.001).
Conclusion: We developed an approach that provided a way to quantify changes in pulmonary Hct using oscillations of hyperpolarized 129Xe signals. This method shows promise for noninvasive pulmonary Hct assessment and disease evaluation.