3D quantitative myocardial perfusion imaging with hyperpolarized HP001(bis-1,1-(hydroxymethyl)-[1- 13 C]cyclopropane-d8): Application of gradient echo and balanced SSFP sequences.

Purpose: This study aims to show the viability of conducting three-dimensional (3D) myocardial perfusion quantification covering the entire heart using both GRE and bSSFP sequences with hyperpolarized HP001.
Methods: A GRE sequence and a bSSFP sequence, both with a stack-of-spirals readout, were designed and applied to three pigs. The images were reconstructed using   13 $$ {}^{13} $$ C coil sensitivity maps measured in a phantom experiment. Perfusion was quantified using a constrained decomposition method, and the estimated rest/stress perfusion values from   13 $$ {}^{13} $$ C GRE/bSSFP and Dynamic contrast-enhanced MRI (DCE-MRI) were individually analyzed through histograms and the mean perfusion values were compared with reference values obtained from PET(   15 $$ {}^{15} $$ O-water). The Myocardial Perfusion Reserve Index (MPRI) was estimated for   13 $$ {}^{13} $$ C GRE/bSSFP and DCE-MRI and compared with the reference values.
Results: Perfusion values, estimated by both DCE and   13 $$ {}^{13} $$ C MRI, were found to be lower than reference values. However, DCE-MRI's estimated perfusion values were closer to the reference values than those obtained from   13 $$ {}^{13} $$ C MRI. In the case of MPRI estimation, the   13 $$ {}^{13} $$ C estimated MPRI values (GRE/bSSFP: 2.3/2.0) more closely align with the literature value (around 3) than the DCE estimated MPRI value (1.6).
Conclusion: This study demonstrated the feasibility of 3D whole-heart myocardial perfusion quantification using hyperpolarized HP001 with both GRE and bSSFP sequences. The   13 $$ {}^{13} $$ C perfusion measurements underestimated perfusion values compared to the   15 $$ {}^{15} $$ O PET literature value, while the   13 $$ {}^{13} $$ C estimated MPRI value aligned better with the literature. This preliminary result indicates   13 $$ {}^{13} $$ C imaging may more accurately estimate MPRI values compared to DCE-MRI.
(© 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.)