Efficacy of proton magnetic resonance spectroscopy in neurological diagnosis and neurotherapeutic decision making

Abstract

Summary:Anatomic and functional neuroimaging with magnetic resonance imaging (MRI) includes the technology more widely known as magnetic resonance spectroscopy (MRS). Now a routine automated "add-on" to all clinical magnetic resonance scanners, MRS, which assays regional neurochemical health and disease, is therefore the most accessible diagnostic tool for clinical management of neurometabolic disorders. Furthermore, the noninvasive nature of this technique makes it an ideal tool for therapeutic monitoring of disease and neurotherapeutic decision making. Among the more than 100 brain disorders that fall within this broad category, MRS contributes decisively to clinical decision making in a smaller but growing number. In this review, we will cover how MRS provides therapeutic impact in brain tumors, metabolic disorders such as adrenoleukodystrophy and Canavan's disease, Alzheimer's disease, hypoxia, secondary to trauma or ischemia, human immunodeficiency virus dementia and lesions, as well as systemic disease such as hepatic and renal failure. Together, these eight indications for MRS apply to a majority of all cases seen. This review, which examines the role of MRS in enhancing routine neurological practice and treatment concludes: 1) there is added value from MRS where MRI is positive; 2) there is unique decision-making information in MRS when MRI is negative; and 3) MRS usefully informs decision making in neurotherapeutics. Additional efficacy studies could extend the range of this capability.

Identification of diffuse and focal brain lesions by clinical magnetic resonance spectroscopy

“…In addition, a recent paper has summarized the application of MRS in certain diseases, including brain tumors, adrenoleukodystrophy, Canavan's disease, Alzheimer's disease, hypoxia and HIV-related dementia (4). However, these resources show a limited number of diseases and do not always show the range of spectral features that may appear with each disease at different echo times.…”

Proton MR spectroscopy of the brain at 3 T: an update

“…Nevertheless, despite the better spectral resolution and higher SNR, the reproducibility of metabolite measurements at 3 T is similar to [28,33] or even worse than [27] that at 1.5 T. This shortfall can be explained by the larger linewidths at 3 T, decreasing both the SNR and the precision of quantitative analysis [27]. High spatial resolution at 3 T, however, reduces the magnetic field inhomogeneity and hampers the contraction of T 2 , decreasing the linewidths, especially for voxels below 0.75 cm 3 . This produces standard errors of the mean comparable in different measurements, suggesting the possibility of achieving high-precision quantification at those resolutions [32].…”

“…All these procedures have been applied to a single voxel with a size ranging from 8 cm 3 to 15.6 cm 3 . Srinivasan et al [61] have recently proposed a TE-averaged PRESS technique for 2D 1 H-MRSI (TE-averaged MRSI) to generate glu maps with a spatial resolution of 1.8 cm 3 and a scan time of about 21 min.…”

“…The metabolites detectable with 1 H-MRS include the prominent resonances of N-acetylaspartate (NAA), choline (Cho) and creatine (Cr), and a variety of other resonances that might or might not be evident depending on the type and quality of spectra as well as on the pathological condition [1][2][3]. Several metabolites, such as lactate in epilepsy or mitochondrial disorders [3], phenylalanine in phenylketonuria [4], guanidinoacetate in guanidinoacetate methyltransferase deficiency [5] and glycine in nonketotic hyperglycinemia [6], can be observed only when their concentrations are several times higher than normal.…”

“…The list is very long and includes brain tumors, degenerative diseases such as Alzheimer's, Huntington's and Parkinson's diseases, cerebrovascular diseases, metabolic disorders such as adrenoleukodystrophy and Canavan's disease, epilepsy, multiple sclerosis and systemic diseases such as hepatic and renal failure [1][2][3]. Rare diseases also studied include creatine deficiency syndrome [7], variant Creutzfeldt-Jakob Disease [8], pantothenate kinase-associated neurodegeneration [9] and Rasmussen's encephalitis [10].…”