In this article, we review the role of MRS in neurologic diagnosis and patient care. Technical discussion focuses on the few remaining issues, localization, spectral display, and interpretation because interesting questions surrounding this widely diverse methodology have been resolved, and a single coherent diagnostic MRS protocol can be applied worldwide on clinical MRI scanners. We provide the most diagnostically useful MRS findings and discuss what is lacking for MRS to become a valuable addition to diagnostic evaluation of neurologic problems. Finally, we muse about the still-underappreciated role of MRS as a molecular neuroimaging technique and predict steady growth of this application as hyperpolarization MR technology approaches the clinic.
"To gain deeper insights into the functional state of brain areas involved in ASD, we carried out a 1H MRI guided spectroscopy examination in adult reeler mice. MRS is a powerful, non-invasive tool for monitoring neurological diseases (101) and it is also used in clinical studies on autistic individuals (102). Abnormalities in neurotransmitter pathways have been associated to ASD, with evidence for a possible implication of glutamatergic, GABAergic, and serotonergic imbalances (102). "
[Show abstract][Hide abstract] ABSTRACT: Autism Spectrum Disorders (ASD) are neurodevelopmental disorders with multifactorial origin characterized by social communication deficits and the presence of repetitive behaviors/interests. Several studies showed an association between the reelin gene mutation and increased risk of ASD and a reduced reelin expression in some brain regions of ASD subjects, suggesting a role for reelin deficiency in ASD etiology. Reelin is a large extracellular matrix glycoprotein playing important roles during development of the central nervous system. To deeply investigate the role of reelin dysfunction as vulnerability factor in ASD, we assessed the behavioral, neurochemical, and brain morphological features of reeler male mice. We recently reported a genotype-dependent deviation in the ultrasonic vocal repertoire and a general delay in motor development of reeler pups. We now report that adult male heterozygous (Het) reeler mice did not show social behavior and communication deficits during male-female social interactions. Wildtype and Het mice showed a typical light/dark locomotor activity profile, with a peak during the central interval of the dark phase. However, when faced with a mild stressful stimulus (a saline injection) only Het mice showed an over response to stress. In addition to the behavioral studies, we conducted high performance liquid chromatography and magnetic resonance imaging and spectroscopy to investigate whether reelin mutation influences brain monoamine and metabolites levels in regions involved in ASD. Low levels of dopamine in cortex and high levels of glutamate and taurine in hippocampus were detected in Het mice, in line with clinical data collected on ASD children. Altogether, our data detected subtle but relevant neurochemical abnormalities in reeler mice supporting this mutant line, particularly male subjects, as a valid experimental model to estimate the contribution played by reelin deficiency in the global ASD neurobehavioral phenotype.
Frontiers in Pediatrics 09/2014; 2:95. DOI:10.3389/fped.2014.00095
"With smaller voxel sizes, specificity of voxel localization , and therefore tissue type, is increased, but SNR is reduced (Freeman, 2003). The use of 1 H-MRS as a prognostic and diagnostic tool is well established (Danielsen and Ross, 1999; Burlina et al., 2000; Tran et al., 2009; Lee et al., 2012). Changes in the 1 H-MRS spectrum reflect general pathology, such as demyelination or ischemia, and is associated with an array of neurological conditions, such as brain tumors (Hollingworth et al., 2006; Hou and Hu, 2009) multiple sclerosis (Gonzalez-Toledo et al., 2006; de Stefano and Filippi, 2007), traumatic brain injury (Marino et al., 2011), and neurodegenerative diseases such as Alzheimer's (Kantarci, 2007; Loos et al., 2010) and Parkinson's disease (Firbank et al., 2002; Rango et al., 2007). "
[Show abstract][Hide abstract] ABSTRACT: Background: Proton Magnetic Resonance Spectroscopy (1H-MRS) is a non-invasive imaging technique that enables quantification of neurochemistry in vivo and thereby facilitates investigation of the biochemical underpinnings of human cognitive variability. Studies in the field of cognitive spectroscopy have commonly focused on relationships between measures of N-acetyl aspartate (NAA), a surrogate marker of neuronal health and function, and broad measures of cognitive performance, such as IQ.
Methodology/Principal Findings: In this study, we used 1H-MRS to interrogate single-voxels in occipitoparietal and frontal cortex, in parallel with assessments of psychometric intelligence, in a sample of 40 healthy adult participants. We found correlations between NAA and IQ that were within the range reported in previous studies. However, the magnitude of these effects was significantly modulated by the stringency of data screening and the extent to which outlying values contributed to statistical analyses.
1H-MRS offers a sensitive tool for assessing neurochemistry non-invasively, yet the relationships between brain metabolites and broad aspects of human behavior such as IQ are subtle. We highlight the need to develop an increasingly rigorous analytical and interpretive framework for collecting and reporting data obtained from cognitive spectroscopy studies of this kind.
Frontiers in Human Neuroscience 02/2014; 8(1):39. DOI:10.3389/fnhum.2014.00039 · 2.99 Impact Factor
"This can be a problem for large and heterogeneous volumes of interest. With proton MRS the following metabolites can be measured : N-acetyl-aspartate (NAA, main peak at 2.02 ppm), sum of creatine and phosphocreatine (main peak at 3.04 and 3.92 ppm), choline (main peak at 3.24 ppm), lactate (main peak at 1.33 ppm), myoinositol, glutamate and glutamine and lipids (broad peaks at 1.3 and 0.9 ppm) and other substances such as citrate (main peak at 2.63 ppm)   . In Figure 8 an example of a brain spectrum of a healthy subject is shown . "
[Show abstract][Hide abstract] ABSTRACT: After more than 20 years of research, a fully integrated PET/MR scanner was launched in 2010 enabling simultaneous acquisition of PET and MR imaging. Currently, no clinical indication for combined PET/MR has been established, however the expectations are high. In this paper we will discuss some of the challenges inherent in this new technology, but focus on potential applications for simultaneous PET/MR in the field of oncology. Methods and tracers for use with the PET technology will be familiar to most readers of this journal; thus this paper aims to provide a short and basic introduction to a number of different MRI techniques, such as DWI-MR (diffusion weighted imaging MR), DCE-MR (dynamic contrast enhanced MR), MRS (MR spectroscopy) and MR for attenuation correction of PET. All MR techniques presented in this paper have shown promising results in the treatment of patients with solid tumors and could be applied together with PET increasing the amount of information about the tissues of interest. The potential clinical benefit of applying PET/MR in staging, radiotherapy planning and treatment evaluation in oncology, as well as the research perspectives for the use of PET/MR in the development of new tracers and drugs will be discussed.
American Journal of Nuclear Medicine and Molecular Imaging 11/2012; 2(4):458-74. · 3.25 Impact Factor
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