Development of specialized magnetic resonance acquisition techniques for human hyperpolarized [13C, 15N2]urea + [1‐13C]pyruvate simultaneous perfusion and metabolic imaging. Issue 3 (8th May 2022)

• Record Type: Journal Article
• Authors: Liu, Xiaoxi; Tang, Shuyu; Mu, Changhua; Qin, Hecong; Cui, Di; Lai, Ying‐Chieh; Riselli, Andrew M.; Delos Santos, Romelyn; Carvajal, Lucas; Gebrezgiabhier, Daniel; Bok, Robert A.; Chen, Hsin‐Yu; Flavell, Robert R.; Gordon, Jeremy W.; Vigneron, Daniel B.; Kurhanewicz, John; Larson, Peder E. Z.
• Is Part Of: Magnetic resonance in medicine. Volume 88:Issue 3(2022)
• Page Start: 1039
• Page End: 1054
• Publication Date: 2022-05-08
• Subjects: 13C hyperpolarization -- bSSFP -- human clinical study -- metabolism imaging -- perfusion imaging -- urea; Nuclear magnetic resonance -- Periodicals; Electron paramagnetic resonance -- Periodicals; 616.07548
• DOI: 10.1002/mrm.29266
• Languages: English
• ISSNs: 0740-3194

Abstract

Abstract : Purpose: This study aimed to develop and demonstrate the in vivo feasibility of a 3D stack‐of‐spiral balanced steady‐state free precession(3D‐bSSFP) urea sequence, interleaved with a metabolite‐specific gradient echo (GRE) sequence for pyruvate and metabolic products, for improving the SNR and spatial resolution of the first hyperpolarized 13 C‐MRI human study with injection of co‐hyperpolarized [1‐ 13 C]pyruvate and [ 13 C, 15 N2 ]urea. Methods: A metabolite‐specific bSSFP urea imaging sequence was designed using a urea‐specific excitation pulse, optimized TR, and 3D stack‐of‐spiral readouts. Simulations and phantom studies were performed to validate the spectral response of the sequence. The image quality of urea data acquired by the 3D‐bSSFP sequence and the 2D‐GRE sequence was evaluated with 2 identical injections of co‐hyperpolarized [1‐ 13 C]pyruvate and [ 13 C, 15 N2 ]urea formula in a rat. Subsequently, the feasibility of the acquisition strategy was validated in a prostate cancer patient. Results: Simulations and phantom studies demonstrated that 3D‐bSSFP sequence achieved urea‐only excitation, while minimally perturbing other metabolites (<1%). An animal study demonstrated that compared to GRE, bSSFP sequence provided an ∼2.5‐fold improvement in SNR without perturbing urea or pyruvate kinetics, and bSSFP approach with a shorter spiral readout reduced blurring artifacts caused by J‐coupling of [ 13 C, 15 N2 ]urea. The human study demonstrated the in vivo feasibility and data quality of the acquisition strategy. Conclusion: The 3D‐bSSFP urea sequence with a stack‐of‐spiral acquisition demonstrated significantly increased SNR and image quality for [ 13 C, 15 N2 ]urea in co‐hyperpolarized [1‐ 13 C]pyruvate and [ 13 C, 15 N2 ]urea imaging studies. This work lays the foundation for future human studies to achieve high‐quality and high‐SNR metabolism and perfusion images.