51. Cardiac T2∗ measurement of hyperpolarized 13C metabolites using metabolite‐selective multi‐echo spiral imaging.
- Author
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Ma, Junjie, Chen, Jun, Reed, Galen D., Hackett, Edward P., Harrison, Crystal E., Ratnakar, James, Schulte, Rolf F., Zaha, Vlad G., Malloy, Craig R., and Park, Jae Mo
- Subjects
HEART metabolism ,METABOLITES ,INJECTIONS ,CARDIAC patients ,POLARIZATION (Nuclear physics) - Abstract
Purpose: Noninvasive imaging with hyperpolarized (HP) pyruvate can capture in vivo cardiac metabolism. For proper quantification of the metabolites and optimization of imaging parameters, understanding MR characteristics such as T2∗s of the HP signals is critical. This study is to measure in vivo cardiac T2∗s of HP [1‐13C]pyruvate and the products in rodents and humans. Methods: A dynamic 13C multi‐echo spiral imaging sequence that acquires [13C]bicarbonate, [1‐13C]lactate, and [1‐13C]pyruvate images in an interleaved manner was implemented for a clinical 3 Tesla system. T2∗ of each metabolite was calculated from the multi‐echo images by fitting the signal decay of each region of interest mono‐exponentially. The performance of measuring T2∗ using the sequence was first validated using a 13C phantom and then with rodents following a bolus injection of HP [1‐13C]pyruvate. In humans, T2∗ of each metabolite was calculated for left ventricle, right ventricle, and myocardium. Results: Cardiac T2∗s of HP [1‐13C]pyruvate, [1‐13C]lactate, and [13C]bicarbonate in rodents were measured as 24.9 ± 5.0, 16.4 ± 4.7, and 16.9 ± 3.4 ms, respectively. In humans, T2∗ of [1‐13C]pyruvate was 108.7 ± 22.6 ms in left ventricle and 129.4 ± 8.9 ms in right ventricle. T2∗ of [1‐13C]lactate was 40.9 ± 8.3, 44.2 ± 5.5, and 43.7 ± 9.0 ms in left ventricle, right ventricle, and myocardium, respectively. T2∗ of [13C]bicarbonate in myocardium was 64.4 ± 2.5 ms. The measurements were reproducible and consistent over time after the pyruvate injection. Conclusion: The proposed metabolite‐selective multi‐echo spiral imaging sequence reliably measures in vivo cardiac T2∗s of HP [1‐13C]pyruvate and products. [ABSTRACT FROM AUTHOR]
- Published
- 2021
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