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Purpose The purpose of this study was to evaluate the feasibility of using a short echo time, 3D H-1 magnetic resonance spectroscopic imaging (MRSI) sequence at 7T to assess the metabolic signature of lesions for patients with glioma. Materials and Methods 29 patients with glioma were studied. MRSI data were obtained using CHESS water suppression, spectrally-selective adiabatic inversion-recovery pulses and automatically prescribed outer-volume-suppression for lipid suppression, and spin echo slice selection (TE=30ms). An interleaved flyback echo-planar trajectory was applied to shorten the total acquisition time (~10min). Relative metabolite ratios were estimated in tumor and in normal-appearing white and gray matter (NAWM, GM). Results Levels of glutamine, myo-inositol, glycine and glutathione relative to total creatine (tCr) were significantly increased in the T2 lesions for all tumor grades compared to those in the NAWM (p < 0.05), while N-acetyl aspartate to tCr were significantly decreased (p < 0.05). In grade 2 gliomas, level of total choline-containing-compounds to tCr was significantly increased (p = 0.0137), while glutamate to tCr was significantly reduced (p = 0.0012). Conclusion The improved sensitivity of MRSI and the increased number of metabolites that can be evaluated using 7T MR scanners is of interest for evaluating patients with glioma. This study has successfully demonstrated the application of a short-echo spin-echo MRSI sequence to detect characteristic differences in regions of tumor versus normal appearing brain.

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Purpose To develop and translate a metabolite‐specific imaging sequence using a symmetric echo planar readout for clinical hyperpolarized (HP) Carbon‐13 (13C) applications. Methods Initial data were acquired from patients with prostate cancer (N = 3) and high‐grade brain tumors (N = 3) on a 3T scanner. Samples of [1‐13C]pyruvate were polarized for at least 2 h using a 5T SPINlab system operating at 0.8 K. Following injection of the HP substrate, pyruvate, lactate, and bicarbonate (for brain studies) were sequentially excited with a singleband spectral‐spatial RF pulse and signal was rapidly encoded with a single‐shot echo planar readout on a slice‐by‐slice basis. Data were acquired dynamically with a temporal resolution of 2 s for prostate studies and 3 s for brain studies. Results High pyruvate signal was seen throughout the prostate and brain, with conversion to lactate being shown across studies, whereas bicarbonate production was also detected in the brain. No Nyquist ghost artifacts or obvious geometric distortion from the echo planar readout were observed. The average error in center frequency was 1.2 ± 17.0 and 4.5 ± 1.4 Hz for prostate and brain studies, respectively, below the threshold for spatial shift because of bulk off‐resonance. Conclusion This study demonstrated the feasibility of symmetric EPI to acquire HP 13C metabolite maps in a clinical setting. As an advance over prior single‐slice dynamic or single time point volumetric spectroscopic imaging approaches, this metabolite‐specific EPI acquisition provided robust whole‐organ coverage for brain and prostate studies while retaining high SNR, spatial resolution, and dynamic temporal resolution.

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Lycium barbarum polysaccharide (LBP), an antioxidant from wolfberry, displays the antioxidative and anti-inflammatory effects on experimental models of insulin resistance in vivo. However, the effective mechanism of LBP on high-fat diet-induced insulin resistance is still unknown. The objective of the study was to investigate the mechanism involved in LBP-mediated phosphatidylinositol 3-kinase (PI3K)/AKT/Nrf2 axis against high-fat-induced insulin resistance. HepG2 cells were incubated with LBP for 12 hrs in the presence of palmitate. C57BL/6J mice were fed a high-fat diet supplemented with LBP for 24 weeks. We analyzed the expression of nuclear factor-E2-related factor 2 (Nrf2), Jun N-terminal kinases (JNK), and glycogen synthase kinase 3β (GSK3β) involved in insulin signaling pathway in vivo and in vitro. First, LBP significantly induced phosphorylation of Nrf2 through PI3K/AKT signaling. Second, LBP obviously increased detoxification and antioxidant enzymes expression and reduced reactive oxygen species (ROS) levels via PI3K/AKT/Nrf2 axis. Third, LBP also regulated phosphorylation levels of GSK3β and JNK through PI3K/AKT signaling. Finally, LBP significantly reversed glycolytic and gluconeogenic genes expression via the activation of Nrf2-mediated cytoprotective effects. In summary, LBP is novel antioxidant against insulin resistance induced by high-fat diet via activation of PI3K/AKT/Nrf2 pathway.

Our study found more 3D MRSI parameters that predicted PFS6 and OS for patients with GBM than did anatomic, diffusion, or perfusion imaging, which were previously evaluated in the same population of patients.

Purpose: To measure T 1 and T 2 relaxation times of metabolites in glioma patients at 3T and to investigate how these values influence the observed metabolite levels. Materials and Methods:A total of 23 patients with gliomas and 10 volunteers were studied with single-voxel two-dimensional (2D) J-resolved point-resolved spectral selection (PRESS) using a 3T MR scanner. Voxels were chosen in normal appearing white matter (WM) and in regions of tumor. The T 1 and T 2 of choline containing compounds (Cho), creatine (Cr), and N-acetyl aspartate (NAA) were estimated.Results: Metabolite T 1 relaxation values in gliomas were not significantly different from values in normal WM. The T 2 of Cho and Cr were statistically significantly longer for grade 4 gliomas than for normal WM but the T 2 of NAA was similar. These differences were large enough to impact the corrections of metabolite levels for relaxation times with tumor grade in terms of metabolite ratios (P Ͻ 0.001). Conclusion:The differential increase in T 2 for Cho and Cr relative to NAA means that the ratios of Cho/NAA and Cr/ NAA are higher in tumor at longer echo times (TEs) relative to values in normal appearing brain. Having this information may be useful in defining the acquisition parameters for optimizing contrast between tumor and normal tissue in MR spectroscopic imaging (MRSI) data, in which limited time is available and only one TE can be used. GLIOMAS ACCOUNT FOR THE MAJORITY of primary brain tumors and vary from benign to malignant. Among all the gliomas, glioblastoma multiforme (GBM) is both the most common and the most malignant, with a relatively poor prognosis. Proton magnetic resonance spectroscopy ( 1 H-MRS) is a powerful noninvasive tool that has been used for the assessment of metabolites in gliomas and the biochemical profiles of brain tumors have been widely studied (1-4). A general marker of brain tumors is the elevation of choline-containing compounds (Cho), which is thought to be due to increased cell density and membrane turnover in neoplasms, and the reduction of the neural marker Nacetyl aspartate (NAA). The availability of higher field strength MR scanners and multichannel radio frequency coils offer the potential of higher signal-to-noise ratio (SNR) and better spectral resolution (5) that can be used to either shorten acquisition time, decrease spatial resolution, or improve detection of other brain metabolites; such as, glutamate (Glu), a main excitatory neurotransmitter; glutamine (Gln), which acts as a detoxifier; and myo-inositol (mI), which is predominantly located within astrocytes.In planning the data acquisition parameters for using MR spectroscopic imaging (MRSI) to determine the spatial extent of tumor vs. normal brain tissue, it is important to consider how to select values that will emphasize the contrast between metabolites in the different regions. Because of the restrictions on clinical scan time, the repetition time (TR) for acquiring MRSI data is often set at one to two seconds and it is usually only possible to acq...