title: Imaging based magnetic resonance spectroscopy (MRS) localization for quantitative neurochemical analysis and cerebral metabolism studies.
abstract: Accurate quantitative metabolic imaging of the brain presents significant challenges due to the complexity and heterogeneity of its structures and compositions with distinct compartmentations of brain tissue types (e.g., gray and white matter). The brain is compartmentalized into various regions based on their unique functions and locations. In vivo magnetic resonance spectroscopy (MRS) techniques allow non-invasive measurements of neurochemicals in either single voxel or multiple voxels, yet the spatial resolution and detection sensitivity of MRS are significantly lower compared with MRI. A fundamentally different approach, namely spectral localization by imaging (SLIM) provides a new framework that overcomes major limitations of conventional MRS techniques. Conventional MRS allows only rectangular voxel shapes that do not conform to the shapes of brain structures or lesions, while SLIM allows compartments with arbitrary shapes. However, the restrictive assumption proposed in the original concept of SLIM, i.e., compartmental homogeneity, led to spectral localization errors, which have limited its broad applications. This review focuses on the recent technical frontiers of image-based MRS localization techniques that overcome the limitations of SLIM through the development and implementation of various new strategies, including incorporation of magnetic field inhomogeneity corrections, the use of multiple receiver coils, and prospective optimization of data acquisition.
authors.affiliation: Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA. Electronic address: plee2@kumc.edu.
authors.forename: Phil
authors.initials: P
authors.lastname: Lee
authors.affiliation: Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Adany
authors.affiliation: Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA.
authors.forename: In-Young
authors.initials: IY
authors.lastname: Choi
mesh_terms: D000818:Animals; D002540:Cerebral Cortex / Q000378:metabolism*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D018377:Neurotransmitter Agents / Q000032:analysis* / Q000378:metabolism
chemical_list: D018377:Neurotransmitter Agents
keywords: Gray matter; Human brain; In vivo; Localization; Magnetic resonance spectroscopy (MRS); Spectral localization by imaging (SLIM); White matter