Creating a clinical platform for carbon‐13 studies using the sodium‐23 and proton resonances. Issue 4 (13th March 2020)

• Record Type: Journal Article
• Authors: Grist, James T.; Hansen, Esben S.S.; Sánchez‐Heredia, Juan D.; McLean, Mary A.; Tougaard, Rasmus; Riemer, Frank; Schulte, Rolf F.; Kaggie, Joshua D.; Ardenkjaer‐Larsen, Jan Henrik; Laustsen, Christoffer; Gallagher, Ferdia A.
• Is Part Of: Magnetic resonance in medicine. Volume 84:Issue 4(2020)
• Page Start: 1817
• Page End: 1827
• Publication Date: 2020-03-13
• Subjects: calibration -- carbon‐13 -- hyperpolarized -- MRI -- sodium‐23; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.28238
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: Calibration of hyperpolarized 13 C‐MRI is limited by the low signal from endogenous carbon‐containing molecules and consequently requires 13 C‐enriched external phantoms. This study investigated the feasibility of using either 23 Na‐MRI or 1 H‐MRI to calibrate the 13 C excitation. Methods: Commercial 13 C‐coils were used to estimate the transmit gain and center frequency for 13 C and 23 Na resonances. Simulations of the transmit B 1 profile of a Helmholtz loop were performed. Noise correlation was measured for both nuclei. A retrospective analysis of human data assessing the use of the 1 H resonance to predict [1‐ 13 C]pyruvate center frequency was also performed. In vivo experiments were undertaken in the lower limbs of 6 pigs following injection of hyperpolarized 13 C‐pyruvate. Results: The difference in center frequencies and transmit gain between tissue 23 Na and [1‐ 13 C]pyruvate was reproducible, with a mean scale factor of 1.05179 ± 0.00001 and 10.4 ± 0.2 dB, respectively. Utilizing the 1 H water peak, it was possible to retrospectively predict the 13 C‐pyruvate center frequency with a standard deviation of only 11 Hz sufficient for spectral–spatial excitation‐based studies. Conclusion: We demonstrate the feasibility of using the 23 Na and 1 H resonances to calibrate the 13 C transmit B 1 using commercially available 13 C‐coils. The method provides a simple approach for in vivo calibration and could improve clinical workflow.