The neurochemical information provided by proton magnetic resonance spectroscopy (MRS) or MR spectroscopic imaging (MRSI) can be severely compromised if strong signals originating from brain water and extracranial lipids are not properly suppressed. The authors of this paper present an overview of advanced water/lipid-suppression techniques and describe their advantages and disadvantages. Moreover, they provide recommendations for choosing the most appropriate techniques for proper use. Methods of water signal handling are primarily focused on the VAPOR technique and on MRS without water suppression (metabolite cycling). The section on lipid-suppression methods in MRSI is divided into three parts. First, lipid-suppression techniques that can be implemented on most clinical MR scanners (volume preselection, outer-volume suppression, selective lipid suppression) are described. Second, lipid-suppression techniques utilizing the combination of k-space filtering, high spatial resolutions and lipid regularization are presented. Finally, three promising new lipid-suppression techniques, which require special hardware (a multi-channel transmit system for dynamic B1+ shimming, a dedicated second-order gradient system or an outer volume crusher coil) are introduced.
Bibliographical noteFunding Information:
Austrian Science Fund, Grant/Award Number: J 4110, P30701, BS; Swiss National Science Foundation, Grant/Award Number: 320030‐175984, RK; US National Institute of Health, Grant/Award Number: P41‐EB015894, P30‐NS076408, IT and DD; P41‐ EB015909, MP; R01‐EB014861, RAG; P41‐EB015891, DMS Funding information 1
The preparation of this manuscript was supported by the US National Institute of Health (P41‐EB015894, P30‐NS076408, IT and DD; P41‐ EB015909, MP; R01‐EB014861, RAG; P41‐EB015891, DMS); the Swiss National Science Foundation (320030–175984, RK); and the Austrian Science Fund (J 4110, P30701, BS).
© 2020 John Wiley & Sons, Ltd.
- crusher coils
- dynamic B shimming
- high spatial resolution
- inversion recovery
- metabolite cycling