Magnetic Resonance Spectroscopy in the Monitoring of Multiple Sclerosis

Abstract

In addition to providing information on tissue structure, magnetic resonance (MR) technology offers the potential to investigate tissue metabolism and function. MR spectroscopy (MRS) offers a wealth of data on the biochemistry of a selected brain tissue volume, which represent potential surrogate markers for the pathology underlying multiple sclerosis (MS). In particular, the N-acetylaspartate peak in an MR spectrum is a putative marker of neuronal and axonal integrity, and the choline peak appears to reflect cell-membrane metabolism. On this basis, a diminished N-acetylaspartate peak is interpreted to represent neuronal/axonal dysfunction or loss, and an elevated choline peak represents heightened cell-membrane turnover, as seen in demyelination, remyelination, inflammation, or gliosis. Therefore, MRS may provide a unique tool to evaluate the severity of MS, establish a prognosis, follow disease evolution, understand its pathogenesis, and evaluate the efficacy of therapeutic interventions, which complements the information obtained from the various forms of assessment made by conventional MR imaging.

Quantitative Cervical Spinal Cord 3T Proton MR Spectroscopy in Multiple Sclerosis

“…[1][2][3][4][5][6][7][8][9][10] T1-and T2-weighted MR imaging is currently the diagnostic reference to define and monitor MS, but it has poor specificity and sensitivity in detecting pathophysiologic MS changes correlated with clinical disability. 6,[11][12][13][14][15] For some years, brain proton MR spectroscopy ( 1 H-MR spectroscopy) has been used to study MS by offering a unique opportunity to evaluate biochemical changes that could shed light on the complex pathophysiology of the disease and potentially define new markers correlated with the clinical evolution of MS. 1,16 Many cerebral quantitative MR spectroscopy studies in patients with MS have evaluated the correlation of the specific single metabolites with specific physiologic events during the MS disease course. 11,17 The N-acetylaspartate (NAA) peak is thought to be a neuronal marker indicative of axonal integrity, and it has been found reduced in acute and chronic lesions and in NAWM and NAGM.…”

“…6,[11][12][13][14][15] For some years, brain proton MR spectroscopy ( 1 H-MR spectroscopy) has been used to study MS by offering a unique opportunity to evaluate biochemical changes that could shed light on the complex pathophysiology of the disease and potentially define new markers correlated with the clinical evolution of MS. 1,16 Many cerebral quantitative MR spectroscopy studies in patients with MS have evaluated the correlation of the specific single metabolites with specific physiologic events during the MS disease course. 11,17 The N-acetylaspartate (NAA) peak is thought to be a neuronal marker indicative of axonal integrity, and it has been found reduced in acute and chronic lesions and in NAWM and NAGM. 1,16 In some cases, the NAA deficit correlated with MS-related clinical disability better than the traditional MR imaging radiologic markers.…”

Hyperpolarized 13 C MR metabolic imaging can detect neuroinflammation in vivo in a multiple sclerosis murine model

“…In line with these observations, lactate has long been suggested as an imaging marker of neuroinflammation in the clinic. A few studies on MS patients have used 1 H magnetic resonance spectroscopy (MRS)/ MRS imaging (MRSI) approaches and detected increased levels of 1 H lactate in gadolinium-enhancing lesions (19,20) as well as in the cerebrospinal fluid of patients with such active lesions (21)(22)(23)(24).…”

Fast quantification of proton magnetic resonance spectroscopic imaging with artificial neural networks

“…The areas of the Lorentzian and Gaussian peaks can be expressed as [29] A(1) = bhπ [16] A(g) = bh π ln(2) [17] The final area of the peak is computed as…”

“…However, these techniques were limited to either single voxel MRS or magnitude spectral data acquired at long echo times (or TE). There is an increasing interest in short echo time MRSI for visualizing short T2 metabolites for improved tissue pathology [17]. In addition, analysis of phased spectra provides more accurate quantification of metabolites.…”