Brain Magnetic Resonance Spectroscopic Imaging Research Articles

Brain temperature, brain metabolites, and immune system phenotypes in temporal lobe epilepsy.

Epileptogenesis is linked to neuroinflammation. We hypothesized that local heat production caused by neuroinflammation can be visualized non-invasively invivo via brain magnetic resonance spectroscopic imaging (MRSI) and MRSI-thermometry (MRSI-t) and that there is a relationship in patients with temporal lobe epilepsy (TLE) between MRSI-t and brain metabolites choline and myo-inositol and between neuroimaging and cellular and serum biomarkers of inflammation. Thirty-six (36) participants, 18 with temporal lobe epilepsy (13 females) and 18 age-matched healthy controls (nine females), were enrolled prospectively and underwent MRSI/MRSI-t; TLE participants also provided blood samples. Temperature was measured using creatine as a reference metabolite. Analysis of Functional NeuroImages 3dttest++ tool was used to analyze voxel-level group differences in temperature, choline, and myo-inositol. Associations with immune cell subsets, cytokines, and chemokines related to inflammation were quantified using correlation coefficients with significant relationships as noted. Patients with TLE showed elevated temperature, choline, and myo-inositol in the temporal lobes. Higher brain temperature was associated with higher levels of cytokines and chemokines, including GM-CSF, TNF, IL-1β, and IL - 12p70, and lower frequency of immune cells including CD3+ T-cells, CD4+ T-cells, CD8+ T-cells, and classical monocytes. Higher choline was associated with higher levels of the cytokines including LT-α, IL-13, and IL-4, and higher myo-inositol was associated with a higher frequency of CD4+ T-cell and CD19+ B-cell subsets and higher levels of cytokines and chemokines including LT-α, IL-13, and CCL3. This study, for the first time, showed that in temporal lobes of patients with TLE temperature and metabolite changes correlate with cellular and serum biomarkers of inflammation. Our results provide support for further development of MRSI-t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool. Neuroinflammation is associated with excessive heat production which can be visualized with magnetic resonance spectroscopic imaging and thermometry (MRSI-t). We prospectively investigated the relationship between MRSI-t and cellular and serum measures of peripheral inflammation in patients with temporal lobe epilepsy (TLE); we compared the results of MRSI-t in patients with TLE to healthy controls. We showed a relationship between the temperature elevations in TLE and elevations of various measures of peripheral inflammation. Our results support further development of MRSI-t as a measure of neuroinflammation in epilepsy and potentially other neurological disorders and as an investigative and clinical tool.

Achieving high-resolution 1H-MRSI of the human brain with compressed-sensing and low-rank reconstruction at 7 Tesla

Low sensitivity MR techniques such as magnetic resonance spectroscopic imaging (MRSI) greatly benefit from the gain in signal-to-noise provided by ultra-high field MR. High-resolution and whole-slab brain MRSI remains however very challenging due to lengthy acquisition, low signal, lipid contamination and field inhomogeneity. In this study, we propose an acquisition-reconstruction scheme that combines 1H free-induction-decay (FID)-MRSI sequence, short TR acquisition, compressed sensing acceleration and low-rank modeling with total-generalized-variation constraint to achieve metabolite imaging in two and three dimensions at 7 Tesla. The resulting images and volumes reveal highly detailed distributions that are specific to each metabolite and follow the underlying brain anatomy. The MRSI method was validated in a high-resolution phantom containing fine metabolite structures, and in five healthy volunteers. This new application of compressed sensing acceleration paves the way for high-resolution MRSI in clinical setting with acquisition times of 5 min for 2D MRSI at 2.5 mm and of 20 min for 3D MRSI at 3.3 mm isotropic.

Altered Neurometabolic Profile in Early Parkinson's Disease: A Study With Short Echo-Time Whole Brain MR Spectroscopic Imaging.

Objective: To estimate alterations in neurometabolic profile of patients with early stage Parkinson's disease (PD) by using a short echo-time whole brain magnetic resonance spectroscopic imaging (wbMRSI) as possible biomarker for early diagnosis and monitoring of PD.Methods: 20 PD patients in early stage (H&Y ≤ 2) without evidence of severe other diseases and 20 age and sex matched healthy controls underwent wbMRSI. In each subject brain regional concentrations of metabolites N-acetyl-aspartate (NAA), choline (Cho), total creatine (tCr), glutamine (Gln), glutamate (Glu), and myo-inositol (mIns) were obtained in atlas-defined lobar structures including subcortical basal ganglia structures (the left and right frontal lobes, temporal lobes, parietal lobes, occipital lobes, and the cerebellum) and compared between patients and matched healthy controls. Clinical characteristics of the PD patients were correlated with spectroscopic findings.Results: In comparison to controls the PD patients revealed altered lobar metabolite levels in all brain lobes contralateral to dominantly affected body side, i.e., decreases of temporal NAA, Cho, and tCr, parietal NAA and tCr, and frontal as well as occipital NAA. The frontal NAA correlated negatively with the MDS-UPDRS II (R = 22120.585, p = 0.008), MDS-UPDRS IV (R = −0.458, p = 0.048) and total MDS-UPDRS scores (R = −0.679, p = 0.001).Conclusion: In early PD stages metabolic alterations are evident in all contralateral brain lobes demonstrating that the neurodegenerative process affects not only local areas by dopaminergic denervation, but also the functional network within different brain regions. The wbMRSI-detectable brain metabolic alterations reveal the potential to serve as biomarkers for early PD.

Neurometabolic changes in aging human brain observed with whole brain magnetic resonance spectroscopic imaging

Neurometabolic changes in aging human brain observed with whole brain magnetic resonance spectroscopic imaging

Whole Brain ¹H-Spectroscopy: A Developing Technique for Advanced Analysis of Cerebral Metabolism.

Accompanying the advance of neuroscientific research and modern therapeutic methods, efforts have been made to develop more practical and effective advanced magnetic resonance (MR) spectroscopic techniques. We present a brief overview on (1)H-MRS techniques in neuroradiological diagnosis and several application examples of recently reported whole brain MR spectroscopic imaging technique (wbMRSI). Despite the benefits of using established (1)H-MRS techniques both single voxel MR spectroscopy (SVS) and chemical shift imaging (CSI) techniques suffer from limited spatial coverage. It is always necessary to define prior to the MRS examination which brain structure is physiologically or pathologically involved and thus should be targeted with (1)H-MRS. In contrast, the advanced wbMRSI allows estimating metabolite changes within a much larger brain region and at multiple brain structures simultaneously. As a developing technique for advanced analysis of cerebral metabolism a wide application of the wbMRSI in both clinical diagnostics and neuroscience could be expected.

Mitochondrial Dysfunction as a Neurobiological Subtype of Autism Spectrum Disorder

Impaired mitochondrial function impacts many biological processes that depend heavily on energy and metabolism and can lead to a wide range of neurodevelopmental disorders, including autism spectrum disorder (ASD). Although evidence that mitochondrial dysfunction is a biological subtype of ASD has grown in recent years, no study, to our knowledge, has demonstrated evidence of mitochondrial dysfunction in brain tissue in vivo in a large, well-defined sample of individuals with ASD. To assess brain lactate in individuals with ASD and typically developing controls using high-resolution, multiplanar spectroscopic imaging; to map the distribution of lactate in the brains of individuals with ASD; and to assess correlations of elevated brain lactate with age, autism subtype, and intellectual ability. Case-control study at Columbia University Medical Center and New York State Psychiatric Institute involving 75 children and adults with ASD and 96 age- and sex-matched, typically developing controls. Lactate doublets (present or absent) on brain magnetic resonance spectroscopic imaging. Lactate doublets were present at a significantly higher rate in participants with ASD (13%) than controls (1%) (P = .001). In the ASD group, the presence of lactate doublets correlated significantly with age (P = .004) and was detected more often in adults (20%) than in children (6%), though it did not correlate with sex, ASD subtype, intellectual ability, or the Autism Diagnostic Observation Schedule total score or subscores. In those with ASD, lactate was detected most frequently within the cingulate gyrus but it was also present in the subcortical gray matter nuclei, corpus callosum, superior temporal gyrus, and pre- and postcentral gyri. In vivo brain findings provide evidence for a possible neurobiological subtype of mitochondrial dysfunction in ASD.

Fusing in vivo and ex vivo NMR sources of information for brain tumor classification

In this study we classify short echo-time brain magnetic resonance spectroscopic imaging (MRSI) data by applying a model-based canonical correlation analyses algorithm and by using, as prior knowledge, multimodal sources of information coming from high-resolution magic angle spinning (HR-MAS), MRSI and magnetic resonance imaging. The potential and limitations of fusing in vivo and ex vivo nuclear magnetic resonance sources to detect brain tumors is investigated. We present various modalities for multimodal data fusion, study the effect and the impact of using multimodal information for classifying MRSI brain glial tumors data and analyze which parameters influence the classification results by means of extensive simulation and in vivo studies. Special attention is drawn to the possibility of considering HR-MAS data as a complementary dataset when dealing with a lack of MRSI data needed to build a classifier. Results show that HR-MAS information can have added value in the process of classifying MRSI data.

Reduced brain choline in homocystinuria due to remethylation defects

To investigate whether secondary impairment of the transmethylation pathway is a mechanism underlying the neurologic involvement in homocystinuria due to remethylation defects. Twelve patients with neurologic disease due to remethylation defects were examined by brain magnetic resonance spectroscopic imaging ((1)H MRSI). Brain N-acetylaspartate, choline-containing compounds (Cho), and creatine (Cr) were quantified and compared to with controls. Metabolites of remethylation cycle and creatine biosynthesis pathway were measured in plasma and urine. MRSI revealed isolated Cho deficiency in all regions examined (mean concentration units +/- SD, patients vs controls): frontal white matter (0.051 +/- 0.010 vs 0.064 +/- 0.010; p = 0.001), lenticular nucleus (0.056 +/- 0.011 vs 0.069 +/- 0.009; p < 0.001), and thalamus (0.063 +/- 0.010 vs 0.071 +/- 0.007; p = 0.006). In contrast to controls, the Cho/Cr ratio decreased with age in patients in the three brain regions examined. Low creatine urinary excretion (p < 0.005), normal urine and plasma guanidinoacetate, and a paradoxical increase in plasma S-adenosylmethionine (p < 0.005) concentrations were observed. Patients with homocystinuria due to remethylation defects have an isolated brain choline deficiency, probably secondary to depletion of labile methyl groups produced by the transmethylation pathway. Although biochemical studies suggest mild peripheral creatine deficiency, brain creatine is in the reference range, indicating a possible compartmentation phenomenon. Paradoxical increase of S-adenosylmethionine suggests that secondary inhibition of methylases contributes to the transmethylation defect in these conditions.

Considerations in applying 3D PRESS H-1 brain MRSI with an eight-channel phased-array coil at 3 T

The purpose of this study was to assess the benefits of a 3 T scanner and an eight-channel phased-array head coil for acquiring three-dimensional PRESS (Point REsolved Spectral Selection) proton (H-1) magnetic resonance spectroscopic imaging (MRSI) data from the brains of volunteers and patients with brain tumors relative to previous studies that used a 1.5 T scanner and a quadrature head coil. Issues that were of concern included differences in chemical shift artifacts, line broadening due to increased susceptibility at higher field strengths, changes in relaxation times and the increased complexity of the postprocessing software due to the need for combining signals from the multichannel data. Simulated and phantom spectra showed that very selective suppression pulses with a thickness of 40 mm and an overpress factor of at least 1.2 are needed to reduce chemical shift artifact and lipid contamination at higher field strengths. Spectral data from a phantom and those from six volunteers demonstrated that the signal-to-noise ratio (SNR) in the eight-channel coil was more than 50% higher than that in the quadrature head coil. For healthy volunteers and eight patients with brain tumors, the SNR at 3 T with the eight-channel coil was on average 1.5 times higher relative to the eight-channel coil at 1.5 T in voxels from normal-appearing brains. In combination with the effect of a higher field strength, the use of the eight-channel coil was able to provide an increase in the SNR of more than 2.33 times the corresponding acquisition at 1.5 T with a quadrature head coil. This is expected to be critical for clinical applications of MRSI in patients with brain tumors because it can be used to either decrease acquisition time or improve spatial resolution.

Spectroscopic imaging of the brain with phased-array coils at 3.0 T

The goal of this study was to develop and evaluate high-resolution magnetic resonance spectroscopic imaging (MRSI) utilizing the gains in signal-to-noise ratio (SNR) provided by combining higher magnetic field with high-sensitivity phased-array (PA) coils. We investigated the maximum improvement in spatial resolution as small as 0.09 cm(3) for brain MRSI while maintaining adequate SNR and acquisition time. The use of low peak power, dual-band spectral-spatial pulses was also investigated for application to 3 T MRSI of the brain using the body coil for radiofrequency excitation and PA coils for signal reception.