Abstract
PurposeWe test the reproducibility of human cardiac phosphorus MRS (31P‐MRS) at ultra‐high field strength (7 T) for the first time. The primary motivation of this work was to assess the reproducibility of a ‘rapid’ 6½ min 31P three‐dimensional chemical shift imaging (3D‐CSI) sequence, which if sufficiently reproducible would allow the study of stress‐response processes. We compare this with an established 28 min protocol, designed to record high‐quality spectra in a clinically feasible scan time. Finally, we use this opportunity to compare the effect of per‐subject B 0 shimming on data quality and reproducibility in the 6½ min protocol.Methods10 healthy subjects were scanned on two occasions: one to test the 28 min 3D‐CSI protocol, and one to test the 6½ min protocol. Spectra were fitted using the OXSA MATLAB toolbox. The phosphocreatine to adenosine triphosphate concentration ratio (PCr/ATP) from each scan was analysed for intra‐ and intersubject variability. The impact of different strategies for voxel selection was assessed.ResultsThere were no significant differences between repeated measurements in the same subject. For the 28 min protocol, PCr/ATP in the midseptal voxel across all scans was 1.91 ± 0.36 (mean ± intersubject SD). For the 6½ min protocol, PCr/ATP in the midseptal voxel was 1.76 ± 0.40. The coefficients of reproducibility (CRs) were 0.49 (28 min) and 0.67 (6½ min). Per‐subject B 0 shimming improved the fitted PCr/ATP precision (for 6½ min scans), but had negligible effect on the CR (0.67 versus 0.66).ConclusionsBoth 7 T protocols show improved reproducibility compared with a previous 3 T study by Tyler et al. Our results will enable informed power calculations and protocol selection for future clinical research studies.
Highlights
Phosphorus MRS (31P‐MRS) is a non‐invasive technique used to measure the concentrations and chemical kinetics of high‐energy phosphorus‐ containing metabolites in the human heart, often collectively referred to as ‘cardiac energetics’. phosphorus MRS (31P‐MRS) has provided a unique insight into our understanding of cardiac metabolism.[1,2] The application of 31P‐MRS to cardiovascular research is of interest, since in most major heart diseases the ratio of phosphocreatine (PCr) to adenosine triphosphate (ATP) concentrations (PCr/ATP) changes, making it a useful indicator of the altered energetic state of the heart
Phosphorus MRS (31P‐MRS) is a non‐invasive technique used to measure the concentrations and chemical kinetics of high‐energy phosphorus‐ containing metabolites in the human heart, often collectively referred to as ‘cardiac energetics’. 31P‐MRS has provided a unique insight into our understanding of cardiac metabolism.[1,2]
We believe that this study reports the first reproducibility data for human cardiac 31P‐MRS at 7 T
Summary
Phosphorus MRS (31P‐MRS) is a non‐invasive technique used to measure the concentrations and chemical kinetics of high‐energy phosphorus‐ containing metabolites in the human heart, often collectively referred to as ‘cardiac energetics’. 31P‐MRS has provided a unique insight into our understanding of cardiac metabolism.[1,2] The application of 31P‐MRS to cardiovascular research is of interest, since in most major heart diseases the ratio of phosphocreatine (PCr) to adenosine triphosphate (ATP) concentrations (PCr/ATP) changes, making it a useful indicator of the altered energetic state of the heart. 31P‐MRS has provided a unique insight into our understanding of cardiac metabolism.[1,2] The application of 31P‐MRS to cardiovascular research is of interest, since in most major heart diseases the ratio of phosphocreatine (PCr) to adenosine triphosphate (ATP) concentrations (PCr/ATP) changes, making it a useful indicator of the altered energetic state of the heart. At 7 T, an increase in SNR of 2.8‐fold in the human heart compared with 3 T has recently been demonstrated,[11] allowing the acquisition in 6 min of spectra of a quality comparable to that of spectra that took 31 min at 3 T. Acquiring usable 31P spectra in shorter scan times is highly desirable; a finer temporal resolution would allow study of the response cardiac energetics to stressors (eg dobutamine infusion or exercise)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call