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 concise model based on hyperpolarized ¹²⁹Xe MR signal oscillations was built for calculating pulmonary Hct. Blood tests and chemical shift saturation recovery were conducted on each rat to obtain Hct. Correlations of Hct obtained from different methods were analyzed using SPSS 22.0.

Results: Hct measurements 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.