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To evaluate the performance of novel spiral MRSI and tissue segmentation pipeline of the brain, to investigate neurometabolic changes in normal-appearing white matter (NAWM) and white matter lesions (WML) of stable relapsing remitting multiple sclerosis (RRMS) compared to healthy controls (HCs).Spiral 3D MRSI using LASER-GOIA-W [16,4] was undertaken on 16 RRMS patients and 9 HCs, to acquire MRSI data from a large volume of interest (VOI) 320 cmCompared to HCs, RRMS demonstrated a statistically significant reduction in all mean brain tissues and increase in CSF volume. Within VOI, WM decreased (-10%) and CSF increased (41%) in RRMS compared to HCs (p 0.001). MRSI revealed that total creatine (tCr) ratios of N-acetylaspartate and glutamate+glutamine in WML were significantly lower than NAWM-MS (-9%, -8%) and HCs (-14%, -10%), respectively. Myo-inositol/tCr in WML was significantly higher than NAWM-MS (14%) and HCs (10%). SVM of MRSI yielded accuracy, sensitivity and specificity of 86%, 95%, and 70%, respectively for HCs vs WML, which were higher than HC vs NAWM and WML vs NAWM models.This study demonstrates the benefit of MRSI in evaluating MS neurometabolic changes in NAWM. SVM of MRSI data in the MS brain may be suited for clinical monitoring and progression of MS patients. Longitudinal MRSI studies are warranted.

Introduction Several studies investigated the changes in diffusion of water molecules in skeletal muscle cells of lifestyle-related-disease patients who performed a hybrid training (HYBT) for six months. They reported that the apparent diffusion coefficient (ADC) and all diffusion eigenvalues (λ1, λ2, and λ3) increased after the HYBT, owing to the enlargement of the intramyocellular diffusion space (intracellular space) caused by the muscular hypertrophy. We assumed that the HYBT promoted metabolism of the whole skeletal muscle including lipids, which reduced the amount of intramyocellular lipid (IMCL), and led to a secondary enlargement of the diffusion space in the skeletal muscle cells. However, the IMCL has to be a diffusion limiting factor in order to verify this hypothesis. Until now, there is no report on whether IMCL is a diffusion limiting factor for water molecules. The objective of this study was to examine whether the IMCL is a diffusion limiting factor in skeletal muscle cells. Materials and methods We performed a three-dimensional quantification of the IMCL in triceps surae muscles of lifestyle-related-disease patients and healthy volunteers. In addition, we measured the ADC in the volume of interest (VOI), diffusion anisotropy (FA), and diffusion eigenvalues (λ1, λ2, and λ3), and evaluated the correlations between these diffusion parameters and IMCL. Results The results showed that the amount of IMCL was positively and negatively correlated with the FA and λ3, respectively, in lifestyle-related-disease patients. In addition, there was a weak negative correlation between IMCL and ADC, λ1, and λ2. There was no correlation between the amount of IMCL and diffusion parameters of healthy volunteers. Discussion Above a certain amount, the IMCL correlates with the diffusion parameters. A higher amount of IMCL leads to smaller diffusion eigenvalues. This result suggested that IMCL possibility of influencing diffusion of water molecules in skeletal muscle cells. However, in order for the influence of IMCL to be reflected in the diffusion eigenvalues, it was needed large amount of IMCL existed, and we thought that the influence was smaller than the influence by the already reported cell membrane.

The primary objective of this study was to develop and validate simultaneous PET/MRI-MRS as a novel biological image-guided approach to neoadjuvant radiotherapy (RT) and/or chemoradiation (chemoRT) in soft tissue sarcomas (STS). A patient with sarcoma of the right thigh underwent PET/MRI scan before and after neoadjuvant (preoperative) radiotherapy. The magnetic resonance imaging (MRI) and 2-deoxy-2-[fluorine-18]-fluoro-D-glucose-Positron Emission Tomography ((18)F-FDG-PET) scans were performed simultaneously. In the post-radiation scan, magnetic resonance spectroscopy (MRS) was subsequently acquired with volume of interest positioned in a residual hyper-metabolic region detected by PET. Post-radiation PET/MRI showed a residual T2-hyperintense mass with significantly reduced (18)F-FDG-uptake, compatible with near complete response to radiotherapy. However, a small region of residual high (18)F-FDG uptake was detected at the tumor margin. MRS of this region had similar metabolite profile as normal tissue, and was thus considered false positive on PET scan. Pathology results were obtained after surgery for confirmation of imaging findings.

Purpose We developed a non-regularized, variable kernel, sophisticated harmonic artifact reduction for phase data (NR-VSHARP) method to accurately estimate local tissue fields without regularization for quantitative susceptibility mapping (QSM). We then used a digital brain phantom to evaluate the accuracy of the NR-VSHARP method, and compared it with the VSHARP and iterative spherical mean value (iSMV) methods through in vivo human brain experiments. Materials and methods Our proposed NR-VSHARP method, which uses variable spherical mean value (SMV) kernels, minimizes L2 norms only within the volume of interest to reduce phase errors and save cortical information without regularization. In a numerical phantom study, relative local field and susceptibility map errors were determined using NR-VSHARP, VSHARP, and iSMV. Additionally, various background field elimination methods were used to image the human brain. Results In a numerical phantom study, the use of NR-VSHARP considerably reduced the relative local field and susceptibility map errors throughout a digital whole brain phantom, compared with VSHARP and iSMV. In the in vivo experiment, the NR-VSHARP-estimated local field could sufficiently achieve minimal boundary losses and phase error suppression throughout the brain. Moreover, the susceptibility map generated using NR-VSHARP minimized the occurrence of streaking artifacts caused by insufficient background field removal. Conclusion Our proposed NR-VSHARP method yields minimal boundary losses and highly precise phase data. Our results suggest that this technique may facilitate high-quality QSM.

An extremely large volume of interest (VOI) approximately 60 dm(3) was used for the measurement of the proton ((1)H) spectrum of the human body. The measurements were performed at 1.5 T with a high-speed spectroscopic imaging technique that uses read gradient during acquisition. The spectrum was computed from coronal 30 mm thick slices of a normal male and female volunteer. The fat/water ratio of the body was used to quantify the fat depots. The results were corrected for relaxation effects and were in good agreement with published values of subjects with comparable body mass index (BMI).

Single slice proton magnetic resonance spectroscopic images were taken from a volume of interest (VOI), which was localised using the point resolved spectroscopy (PRESS) sequence. Non-uniformities in the excitation profile of the VOI within the image plane were accounted for using a uniformity correction image. Metabolite images were divided on a voxel-by-voxel basis with a water image obtained from a VOI of the same spatial dimensions from a phantom acquisition. Normalisation procedures carried out on phantom metabolite images were needed to account for the spatial shift in the excitation profile of the VOI, which varies linearly with the chemical shift of the metabolite. Patient metabolite images were then normalised using a VOI water image from a phantom acquisition, which was spatially shifted according to the metabolite chemical shift. In a study of 14 stroke patients, metabolite maps of the distribution of choline, creatine and N-acetyl aspartate (NAA) were constructed. The spectral signal intensities from these metabolites in the infarcted and in the contralateral region were calculated using the raw maps and secondly with the same maps after the B1 normalisation process. In the initial analysis only the metabolite NAA showed a significant decrease, whilst all three metabolites showed a significant reduction in the normalised analysis. These results confirm that normalisation of PRESS localised images does have a significant bearing upon any quantitative measurements made using such images.