Cardiac T2∗ measurement of hyperpolarized 13C metabolites using metabolite‐selective multi‐echo spiral imaging. Issue 3 (6th April 2021)

• Record Type: Journal Article
• Authors: Ma, Junjie; Chen, Jun; Reed, Galen D.; Hackett, Edward P.; Harrison, Crystal E.; Ratnakar, James; Schulte, Rolf F.; Zaha, Vlad G.; Malloy, Craig R.; Park, Jae Mo
• Is Part Of: Magnetic resonance in medicine. Volume 86:Issue 3(2021)
• Page Start: 1494
• Page End: 1504
• Publication Date: 2021-04-06
• Subjects: T2∗ -- dynamic nuclear polarization -- heart -- hyperpolarized pyruvate -- multi‐echo spiral imaging; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.28796
• Languages: English
• ISSNs: 0740-3194

Abstract

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 T 2 ∗ s of the HP signals is critical. This study is to measure in vivo cardiac T 2 ∗ s of HP [1‐ 13 C]pyruvate and the products in rodents and humans. Methods: A dynamic 13 C multi‐echo spiral imaging sequence that acquires [ 13 C]bicarbonate, [1‐ 13 C]lactate, and [1‐ 13 C]pyruvate images in an interleaved manner was implemented for a clinical 3 Tesla system. T 2 ∗ 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 T 2 ∗ using the sequence was first validated using a 13 C phantom and then with rodents following a bolus injection of HP [1‐ 13 C]pyruvate. In humans, T 2 ∗ of each metabolite was calculated for left ventricle, right ventricle, and myocardium. Results: Cardiac T 2 ∗ s of HP [1‐ 13 C]pyruvate, [1‐ 13 C]lactate, and [ 13 C]bicarbonate in rodents were measured as 24.9 ± 5.0, 16.4 ± 4.7, and 16.9 ± 3.4 ms, respectively. In humans, T 2 ∗ of [1‐ 13 C]pyruvate was 108.7 ± 22.6 ms in left ventricle and 129.4 ± 8.9 ms in right ventricle. T 2 ∗ of [1‐ 13 C]lactate was 40.9 ± 8.3, 44.2 ± 5.5, and 43.7 ± 9.0 ms in left ventricle, right ventricle, and myocardium, respectively. T 2 ∗ of [ 13 C]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 T 2 ∗ s of HP [1‐ 13 C]pyruvate and products.