Glycerophosphocholine and Glycerophosphoethanolamine Are Not the Main Sources of the In Vivo 31P MRS Phosphodiester Signals from Healthy Fibroglandular Breast Tissue at 7 T

Purpose: The identification of the phosphodiester (PDE) P-31 MR signals in the healthy human breast at ultra-high field. Methods: In vivo 3'P MRS measurements at 7 T of the PDE signals in the breast were performed investigating the chemical shifts, the transverse-and the longitudinal relaxation times. Chemical shifts and transverse relaxation times were compared with non-ambiguous PDE signals from the liver. Results: The chemical shifts of the PDE signals are shifted-0.5 ppm with respect to glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE), and the transverse and longitudinal relaxation times for these signals are a factor 3 to 4 shorter than expected for aqueous GPC and GPE. Conclusion: The available experimental evidence suggests that GPC and GPE are not the main source of the PDE signals measured in fibroglandular breast tissue at 7 T. These signals may predominantly originate from mobile phospholipids.