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(18)F-FDG PET/MRI might be the diagnostic method of choice for Hodgkin lymphoma patients, as it combines significant metabolic information from PET with excellent soft-tissue contrast from MRI and avoids radiation exposure from CT. However, a major issue is longer examination times than for PET/CT, especially for younger children needing anesthesia. Thus, a targeted selection of suitable whole-body MRI sequences is important to optimize the PET/MRI workflow. Methods: The initial PET/MRI scans of 84 EuroNet-PHL-C2 study patients from 13 international PET centers were evaluated. In each available MRI sequence, 5 PET-positive lymph nodes were assessed. If extranodal involvement occurred, 2 splenic lesions, 2 skeletal lesions, and 2 lung lesions were also assessed. A detection rate was calculated dividing the number of visible, anatomically assignable, and measurable lesions in the respective MRI sequence by the total number of lesions. Results: Relaxation time–weighted (T2w) transverse sequences with fat saturation (fs) yielded the best result, with detection rates of 95% for nodal lesions, 62% for splenic lesions, 94% for skeletal lesions, and 83% for lung lesions, followed by T2w transverse sequences without fs (86%, 49%, 16%, and 59%, respectively) and longitudinal relaxation time–weighted contrast-enhanced transverse sequences with fs (74%, 35%, 57%, and 55%, respectively). Conclusion: T2w transverse sequences with fs yielded the highest detection rates and are well suited for accurate whole-body PET/MRI in lymphoma patients. There is no evidence to recommend the use of contrast agents.

Background The ultra-high risk (UHR) paradigm allows early contact with patients developing acute psychosis and the study of treatment effects on the underlying pathology. Methods 29 patients with first acute psychosis according to CAARMS criteria (transition patients, TP) (T0) and thereof 22 patients after two-year follow-up (mean 788 d) (T1) underwent 1H-/31P-MR spectroscopy of the prefrontal (DLPFC) and anterior midcingulate (aMCC) cortices and the thalamus. N-acetylaspartate (NAA), glutamate (Glu, Glx), energy (PCr, ATP) and phospholipid metabolites (PME, PDE) were compared to 27 healthy controls by ANCOVA and correlated with patients' symptom ratings (BPRS-E, SCL-90R). For longitudinal analysis, linear mixed model (LMM) and ANCOVA for repeated measures were used. Results DLPFC : In patients, NAA and PME were decreased bilaterally and Glu on the left side at T0. Left-sided Glu and NAA (trend) and bilateral Glx increased during follow-up. Thalamus : In TP, bilateral NAA, left-sided Glu and right-sided Glx were decreased at T0; bilateral NAA and left-sided Glx increased during follow-up. aMCC : In TP, bilateral NAA, right-sided Glu, and bilateral PME and PDE were decreased, while left-sided PCr was increased at T0. No changes were observed during follow-up. Conclusion Regardless of the long-term diagnosis, the psychotic state of illness includes disturbed neuronal function in the DLPFC, thalamus and aMCC. Treatment-as-usual (TAU), including antipsychotic/antidepressant medication and supportive psychotherapy, had an effect on the thalamo-frontal area but not or less pronounced on the neurometabolic deficits of the aMCC.

Purpose To assess the additional value of quantitative tCho evaluation to diagnose malignancy and lymph node metastases in suspicious lesions on multiparametric breast MRI (mpMRI, BI-RADS 4, and BI-RADS 5). Methods One hundred twenty-one patients that demonstrated suspicious multiparametric breast MRI lesions using DCE, T2w, and diffusion-weighted (DW) images were prospectively enrolled in this IRB-approved study. All underwent single-voxel proton MR spectroscopy (1H-MRS, point-resolved spectroscopy sequence, TR 2000 ms, TE 272 ms) with and without water suppression. The total choline (tCho) amplitude was measured and normalized to millimoles/liter according to established methodology by two independent readers (R1, R2). ROC-analysis was employed to predict malignancy and lymph node status by tCho results. Results One hundred three patients with 74 malignant and 29 benign lesions had full 1H-MRS data. The area under the ROC curve (AUC) for prediction of malignancy was 0.816 (R1) and 0.809 (R2). A cutoff of 0.8 mmol/l tCho could diagnose malignancy with a sensitivity of > 95%. For prediction of lymph node metastases, tCho measurements achieved an AUC of 0.760 (R1) and 0.788 (R2). At tCho levels Conclusion Quantitative tCho evaluation from 1H-MRS allowed diagnose malignancy and lymph node status in breast lesions suspicious on multiparametric breast MRI. tCho therefore demonstrated the potential to downgrade suspicious mpMRI lesions and stratify the risk of lymph node metastases for improved patient management. Key Points • Quantitative tCho evaluation can distinguish benign from malignant breast lesions suspicious after multiparametric MRI assessment. • Quantitative tCho levels are associated with lymph node status in breast cancer. • Quantitative tCho levels are higher in hormonal receptor positive compared to hormonal receptor negative lesions.

Functional reorganisation of the salience network (SN) has been proposed as one of the key pathomechanisms associated with central nociceptive processing in the chronic pain state. Being associated with an altered functional connectivity within the SN, these processes have been hypothesized to result from a loss of inhibitory function leading to node hyperexcitability and spontaneous pain. Combined resting-state BOLD functional magnetic resonance imaging (MRI) and 1 H-MR spectroscopy was applied to chronic back pain patients and healthy subjects to assess deviations from functional integrity (weighted closeness centrality [wCC], derived from resting-state functional MRI), oscillatory BOLD characteristics (spectral power), and neurotransmitter levels (GABA + , glutamate+glutamine) in 2 key SN nodes, anterior insular (aIns R ) and anterior mid-cingulate cortices. In addition, examinations were repeated in chronic back pain patients after a 4-week interdisciplinary multimodal pain treatment and in healthy subjects after 4 weeks to explore longitudinal, treatment-mediated changes in target variables. The aIns R and, to a lesser extent, the anterior mid-cingulate of patients exhibited significantly reduced wCC accompanied by a spectral power shift from a lower to a higher frequency band, indicating a desynchronization of their neuronal activity within the SN, possibly because of increased spontaneous activations. Without revealing neurotransmitter differences, patients alone showed significant positive associations between local GABA + levels and wCC in aIns R , suggesting a stronger dependence of node synchronization on the inhibitory tone in the chronic pain state. However, this needs to be explored in the future using magnetic resonance spectroscopy techniques that are more sensitive to detecting subtle neurotransmitter changes and also allow multifocal characterization of neurotransmitter tone.

Machine learning classifications of first-episode psychosis (FEP) using neuroimaging have predominantly analyzed brain volumes. Some studies examined cortical thickness, but most of them have used parcellation approaches with data from single sites, which limits claims of generalizability. To address these limitations, we conducted a large-scale, multi-site analysis of cortical thickness comparing parcellations and vertex-wise approaches. By leveraging the multi-site nature of the study, we further investigated how different demographical and site-dependent variables affected predictions. Finally, we assessed relationships between predictions and clinical variables. 428 subjects (147 females, mean age 27.14) with FEP and 448 (230 females, mean age 27.06) healthy controls were enrolled in 8 centers by the ClassiFEP group. All subjects underwent a structural MRI and were clinically assessed. Cortical thickness parcellation (68 areas) and full cortical maps (20,484 vertices) were extracted. Linear Support Vector Machine was used for classification within a repeated nested cross-validation framework. Vertex-wise thickness maps outperformed parcellation-based methods with a balanced accuracy of 66.2% and an Area Under the Curve of 72%. By stratifying our sample for MRI scanner, we increased generalizability across sites. Temporal brain areas resulted as the most influential in the classification. The predictive decision scores significantly correlated with age at onset, duration of treatment, and positive symptoms. In conclusion, although far from the threshold of clinical relevance, temporal cortical thickness proved to classify between FEP subjects and healthy individuals. The assessment of site-dependent variables permitted an increase in the across-site generalizability, thus attempting to address an important machine learning limitation.

The aim of this retrospective cross-sectional study was to provide an MRI-based examination framework of venous malformations (VMs) infiltrating the sciatic nerve and determine the frequency of nerve infiltration patterns and muscle involvement in correlation to the patients’ quality of life. Pelvic and lower limb MR images of 378 patients with vascular malformations were examined retrospectively. Pain levels and restriction of motion were evaluated with a questionnaire. Cross-sectional areas of affected nerves were compared at standardized anatomical landmarks. Intraneural infiltration patterns and involvement of muscles surrounding the sciatic nerve were documented. Sciatic nerve infiltration occurred in 23/299 patients (7.7%) with VM. In all cases (23/23; 100%), gluteal or hamstring muscles surrounding the nerve were affected by the VM. Infiltrated nerves were enlarged and showed signal alterations (T2-hyperintensity) compared to the unaffected side. Enlarged nerve cross-sectional areas were associated with elevated pain levels. Three nerve infiltration patterns were observed: subepineurial (12/23; 52.2%), subparaneurial (6/23; 26.1%) and combined (5/23; 21.7%) infiltration. This study provides a clinically relevant assessment for sciatic nerve infiltration patterns and muscle involvement of VMs, while suggesting that VMs in gluteal and hamstring muscles require closer investigation of the sciatic nerve by the radiologist.

Background Personality disorders (PD) belong to the most common and most serious mental disorders as regards social dysfunction, inability to work, occurrence of comorbidity and suicidal risk. PDs also crucially influence the incidence, clinical course and treatment response of mental disorders with high suicidal risk, such as depression or substance abuse. One key issue of PD concerns the regulation of emotions. Methods Both 1H-/31P-Chemical Shift Imaging (CSI) was applied in a single session to assess neurochemical markers of glutamate function (NAA, Glu) and local energy metabolism (PCr, ATP) in two patient cohorts encompassing 22 cluster B (CB) and 21 cluster C (CC) PD patients, whereby 10 patients of each group were on low-dose antidepressants, and in 60 healthy controls (HC). Non-parametric statistical tests and correlation analyses were performed to assess disease effects on the metabolites and their relation to symptomatology as assessed by SCL-90R self-ratings. Results Overall comparison including Bonferroni correction revealed significant differences of Glu across all groups in the dorsolateral prefrontal cortex (DLPFC). The following uncorrected results of pairwise tests were obtained: (i) Glu was bilaterally increased in the DLPFC in CB patients, whereas it was – together with NAA – bilaterally decreased in the DLPFC in CC patients and accompanied by increased PCr in the left DLPFC. (ii) NAA and Glu, accompanied by increased PCr, were significantly decreased in the dorsomedial prefrontal cortex (DMPFC) in CC patients. (iii) NAA was decreased in the right anterior cingulate cortex (ACC) in CB patients, and in the left ACC in CC patients with PCr being increased bilaterally. (iv) No associations were observed between metabolites and psychopathology measures. Conclusion The observations in the DLPFC may reflect a neurobiochemical correlate of disturbed cognitive control function in CB and CC PD. While the alterations in CB patients suggest increased basal activity, the observed patterns in CC patients likely reflect decreased or inhibited activity. The alterations of NAA and Glu levels in the ACC and DMPFC indirectly support the assumption of disturbed neuronal function in regions involved in social cognition and mentalizing abilities in both CB and CC PD. Further studies should include the investigation of metabolites of neuronal inhibition (GABA) and the examination of treatment effects.

To explore brain activity and the related neurochemical processes, current research focuses increasingly on the combined acquisition of 1 H MR spectra and fMRI data to investigate potential associations between local metabolite resting state levels and stimulus-induced BOLD signal changes. In this study, whole-brain fMRI measurements and localized functional 1 H MEGA-PRESS MRS scans were conducted at 3T in healthy subjects prior to and during acute pain stimulation to quantify resting state GABA+/tCr and Glx/tCr levels in the insular cortex together with their stimulus-induced changes and to explore associations between these neurochemical parameters with intra-regional but also inter-regional BOLD responses. Inter-regionally, a significant negative correlation between the BOLD signal of a cluster in the supplementary motor area with overlap to the mid-cingulate cortex (R = −0.56, p = 0.004) and the insular resting state GABA+/tCr was obtained. Furthermore, pain induced insular ΔGlx was significantly positively associated with the BOLD signal in the left superior frontal gyrus, left and right inferior frontal gyrus, left inferior parietal lobe, left superior temporal gyrus, left anterior insula and right posterior insula, with R values ranging from 0.59 to 0.73 (p

Phase and frequency corrections of magnetic resonance spectroscopic data are of major importance to obtain reliable and unambiguous metabolite estimates as validated in recent research for single-shot scans with the same spectral fingerprint. However, when using the J-difference editing technique 1 H MEGA-PRESS, misalignment between mean edited ( ON ‾ ) and non-edited ( OFF ‾ ) spectra that may remain even after correction of the corresponding individual single-shot scans results in subtraction artefacts compromising reliable GABA quantitation. We present a fully automatic routine that iteratively optimizes simultaneously relative frequencies and phases between the mean ON ‾ and OFF ‾ 1 H MEGA-PRESS spectra while minimizing the sum of the magnitude of the difference spectrum ( L 1 norm). The proposed method was applied to simulated spectra at different SNR levels with deliberately preset frequency and phase errors. Difference optimization proved to be more sensitive to small signal fluctuations, as e.g. arising from subtraction artefacts, and outperformed the alternative spectral registration approach, that, in contrast to our proposed linear approach, uses a nonlinear least squares minimization ( L 2 norm), at all investigated levels of SNR. Moreover, the proposed method was applied to 47 MEGA-PRESS datasets acquired in vivo at 3 T. The results of the alignment between the mean OFF ‾ and ON ‾ spectra were compared by applying (a) no correction, (b) difference optimization or (c) spectral registration. Since the true frequency and phase errors are not known for in vivo data, manually corrected spectra were used as the gold standard reference (d). Automatically corrected data applying both, method (b) or method (c), showed distinct improvements of spectra quality as revealed by the mean Pearson correlation coefficient between corresponding real part mean DIFF ‾ spectra of R bd = 0.997 ± 0.003 (method (b) vs. (d)), compared to R ad = 0.764 ± 0.220 (method (a) vs. (d)) with no alignment between OFF ‾ and ON ‾ . Method (c) revealed a slightly lower correlation coefficient of R cd = 0.972 ± 0.028 compared to R bd , that can be ascribed to small remaining subtraction artefacts in the final DIFF ‾ spectrum. In conclusion, difference optimization performs robustly with no restrictions regarding the input data range or user intervention and represents a complementary tool to optimize the final DIFF ‾ spectrum following the mandatory frequency and phase corrections of single ON and OFF scans prior to averaging.

Purpose The objective of the study was to investigate the reproducibility of exercise induced pH-heterogeneity by splitting of the inorganic phosphate (Pi) signal in the corresponding 31 P-MRS spectra and to compare results of this approach with other fiber-type related markers, like phosphocreatine/adenosine triphosphate (PCr/ATP) ratio, and PCr-recovery parameters. Material and methods Subjects ( N = 3) with different sportive background were tested in 10 test sessions separated by at least 3 days. A MR-compatible pedal ergometer was used to perform the exercise and to induce a pH-based splitting of the Pi-signal in 31 P-MR spectra of the medial gastrocnemius muscle. The PCr recovery was analyzed using a non-negative least square algorithm (NNLS) and multi-exponential regression analysis to estimate the number of non-exponential components as well as their amplitude and time constant. The reproducibility of the estimated metabolic marker and the resulting fiber-type distributions between the 10 test sessions were compared. Results The reproducibility (standard deviation between measurements) based on (1) Pi components varied from 2% to 4%, (2) PCr recovery time components varied from 10% to 12% and (3) phosphate concentrations at rest varied from 8% to 11% between test sessions. Due to the sportive activity differences between the 3 subjects were expected in view of fiber type distribution. All estimated markers indicate the highest type I percentage for volunteer 3 medium for volunteer 2 and the lowest for volunteer 1. Conclusions The relative high reproducibility of pH dependent Pi components during exercise indicates a high potential of this method to estimate muscle fiber-type distributions in vivo. To make this method usable not only to detect differences in muscle fiber distributions but also to determine individual fiber-type volume contents it is therefore recommended to validate this marker by histological methods and to reveal the effects of muscle fiber recruitments and fiber-type specific Pi concentrations on the intensity ratios between the splitted Pi-components.

Objective The aim of this study was to evaluate the safety and clinical outcomes of percutaneous sclerotherapy of venous disorders of the labia majora in patients with vascular malformations of the lower limbs. Methods Thirty percutaneous sclerotherapy treatments were performed over a 6-year period among 17 female patients with symptomatic venous malformation (VM) or secondary varicosis of the labia majora. Four patients were treated with sclerotherapy alone, 13 patients had additional procedures to control the VM before sclerotherapy. Polidocanol was used as sclerosant. Indications for sclerotherapy included pain, bleeding, thrombophlebitis, and swelling. Genitourinary symptoms were recorded. The number of treatments and procedure-related complications were registered. Complications were classified according to the Society of Interventional Radiology (SIR) classification system (grade A-E). The 3-month postintervention follow-up included magnetic resonance imaging, clinical examination, and a symptom-related questionnaire. If no reintervention was necessary, consultation was scheduled biannually. Results All patients had local swelling and pain; only a fraction of the patients had further symptoms with bleeding or thrombophlebitis (47% each). Eight patients required reintervention. No major complications were observed; minor complications such as postprocedural swelling occurred in 29% (SIR grade A), pain occurred in 17% (SIR grade B), and skin blistering developed in 5% (SIR grade B). Upon follow-up examination after a median of 40 months, 76% showed complete relief of symptoms, and 23% reported partial relief. All patients reported a substantial reduction in pain (75% >5 points in visual analogue scale) and swelling (88% complete cessation). Conclusions Percutaneous sclerotherapy is a safe and effective treatment option of VM and secondary varicosis of the labia majora.

The ultra-high risk (UHR) paradigm allows early contact with patients developing acute psychosis and the study of treatment effects on the underlying pathology.29 patients with first acute psychosis according to CAARMS criteria (transition patients, TP) (T0) and thereof 22 patients after two-year follow-up (mean 788 d) (T1) underwentDLPFC: In patients, NAA and PME were decreased bilaterally and Glu on the left side at T0. Left-sided Glu and NAA (trend) and bilateral Glx increased during follow-up. Thalamus: In TP, bilateral NAA, left-sided Glu and right-sided Glx were decreased at T0; bilateral NAA and left-sided Glx increased during follow-up. aMCC: In TP, bilateral NAA, right-sided Glu, and bilateral PME and PDE were decreased, while left-sided PCr was increased at T0. No changes were observed during follow-up.Regardless of the long-term diagnosis, the psychotic state of illness includes disturbed neuronal function in the DLPFC, thalamus and aMCC. Treatment-as-usual (TAU), including antipsychotic/antidepressant medication and supportive psychotherapy, had an effect on the thalamo-frontal area but not or less pronounced on the neurometabolic deficits of the aMCC.

Background The ultra-high risk (UHR) paradigm allows the investigation of individuals at increased risk of developing psychotic or other mental disorders with the aim of making prevention and early intervention as specific as possible in terms of the individual outcome. Methods Single-session 1H-/31P-Chemical Shift Imaging of thalamus, prefrontal (DLPFC) and anterior midcingulate (aMCC) cortices was applied to 69 UHR patients for psychosis and 61 matched healthy controls. N-acetylaspartate (NAA), glutamate/glutamine complex (Glx), energy (PCr, ATP) and phospholipid metabolites were assessed, analysed by ANOVA (or ANCOVA [with covariates]) and correlated with symptomatology (SCL-90R). Results The thalamus showed decreased NAA, inversely correlated with self-rated aggressiveness, as well as increased PCr, and altered phospholipid breakdown. While the aMCC showed a pattern of NAA decrease and PCr increase, the DLPFC showed PCr increase only in the close-to-psychosis patient subgroup. There were no specific findings in transition patients. Conclusion The results do not support the notion of a specific pre-psychotic neurometabolic pattern, but likely reflect correlates of an “at risk for mental disorders syndrome”. This includes disturbed neuronal (mitochondrial) metabolism in the thalamus and aMCC, with emphasis on left-sided structures, and altered PL remodeling across structures.

Purpose The aim of the study was to examine pH heterogeneity during fatigue induced by neuromuscular electrical stimulation (NMES) using phosphorus magnetic resonance spectroscopy (31P-MRS). It is hypothesized that three pH components would occur in the 31P-MRS during fatigue, representing three fiber types. Methods The medial gastrocnemius of eight subjects was stimulated within a 3-Tesla whole body MRI scanner. The maximal force during stimulation (Fstim) was examined by a pressure sensor. Phosphocreatine (PCr), adenosintriphosphate, inorganic phosphate (Pi), and the corresponding pH were estimated by a nonvolume-selective 31P-MRS using a small loop coil at rest and during fatigue. Results During fatigue, Fstim and PCr decreased to 27% and 33% of their initial levels, respectively. In all cases, the Pi peak increased when NMES was started and split into three different peaks. Based on the single Pi peaks during fatigue, an alkaline (6.76 ± 0.08), a medium (6.40 ± 0.06), and an acidic (6.09 ± 0.05) pH component were observed compared to the pH (7.02 ± 0.02) at rest. Conclusion It is suggested that NMES is able to induce pH heterogeneity in the medial gastrocnemius, and that the single Pi peaks represent the different muscle fiber types of the skeletal muscle. Magn Reson Med 77:2097–2106, 2017. © 2016 International Society for Magnetic Resonance in Medicine

Background The manifestation of chronic pain and psychological impairments are related to alterations of neurotransmitter metabolism in cerebral pain processing regions, e.g., anterior cingular cortex (ACC), insula. Magnetic resonance spectroscopy ((1)H-MRS) enables in vivo quantification of neurotransmitters in the brain and was applied in this study to examine the hypothesized chronic pain-related imbalance between excitatory (glutamatergic) and inhibitory (GABA-ergic) neurotransmitter turnovers in the brain of patients with nonspecific chronic pain. Materials and methods A total of 19 patients with nonspecific chronic (> 3 months) back pain and 19 age- and gender-matched healthy subjects participated in this study. Glutamate and GABA as well as glutamate/GABA ratios were determined in the ACC and insula using (1)H-MRS. Sociodemographic, psychological, and pain-related features were measured with standardized questionnaires. Results There was a strong variance of glutamate/GABA ratios for both patients and healthy subjects with no significant difference between the two groups. Regression analysis revealed certain significant predictors, such as anxiety as causal variable for reduced glutamate and depression and age as predictors for reduced GABA in ACC. In the patient group, intensity of pain was a significant predictor for glutamate and GABA levels in the insula. Conclusions Despite the uniform diagnosis of nonspecific chronic back pain, we observed a strong variance of neurotransmitters in cerebral pain processing regions. It is necessary to include psychological as well as clinical parameters (e.g., intensity of pain or depression) for a proper interpretation of neurotransmitter turnovers.

Hippocampal pathology has been shown to be central to the pathophysiology of schizophrenia and a putative risk marker for developing psychosis. We applied both (1)H MRS (proton magnetic resonance spectroscopy) at 3Tesla and voxel-based morphometry (VBM) of high-resolution brain structural images in order to study the association of the metabolites glutamate (Glu) and N-acetyl-aspartate (NAA) in the hippocampus with whole-brain morphometry in 31 persons at ultra-high-risk for psychosis (UHR), 18 first-episode schizophrenia patients (Sz), and 42 healthy controls (all subjects being neuroleptic-naïve). Significantly diverging associations emerged for UHR subjects hippocampal glutamate showed positive correlation with the left superior frontal cortex, not seen in Sz or controls, while in first-episode schizophrenia patients a negative correlation was significant between glutamate and a left prefrontal area. For NAA, we observed different associations for left prefrontal and caudate clusters bilaterally for both high-risk and first-episode schizophrenia subjects, diverging from the pattern seen in healthy subjects. Our results suggest that associations of hippocampal metabolites in key areas of schizophrenia might vary due to liability to or onset of the disorder.

Interventional studies suggest that changes in physical fitness affect brain function and structure. We studied the influence of high intensity physical exercise on hippocampal volume and metabolism in 17 young healthy male adults during a 6-week exercise program compared with matched controls. We further aimed to relate these changes to hypothesized changes in exercised-induced brain-derived neurotrophic factor (BDNF), interleukin-6 (IL-6), and tumor necrosis factor alpha (TNF-α). We show profound improvement of physical fitness in most subjects and a positive correlation between the degree of fitness improvement and increased BDNF levels. We unexpectedly observed an average volume decrease of about 2%, which was restricted to right hippocampal subfields CA2/3, subiculum, and dentate gyrus and which correlated with fitness improvement and increased BDNF levels negatively. This result indicates that mainly those subjects who did not benefit from the exercise program show decreased hippocampal volume, reduced BDNF levels, and increased TNF-α concentrations. While spectroscopy results do not indicate any neuronal loss (unchanged N-acetylaspartate levels) decreased glutamate-glutamine levels were observed in the right anterior hippocampus in the exercise group only. Responder characteristics need to be studied in more detail. Our results point to an important role of the inflammatory response after exercise on changes in hippocampal structure.

Early intervention research in schizophrenia has suggested that brain structural alterations might be present in subjects at high risk of developing psychosis. The heterogeneity of regional effects of these changes, which is established in schizophrenia, however, has not been explored in prodromal or high-risk populations. We used high-resolution MRI and voxel-based morphometry (VBM8) to analyze grey matter differences in 43 ultra high-risk subjects for psychosis (meeting ARMS criteria, identified through CAARMS interviews), 24 antipsychotic-naïve first-episode schizophrenia patients and 49 healthy controls (groups matched for age and gender). Compared to healthy controls, resp., first-episode schizophrenia patients had reduced regional grey matter in left prefrontal, insula, right parietal and left temporal cortices, while the high-risk group showed reductions in right middle temporal and left anterior frontal cortices. When dividing the ultra-high-risk group in those with a genetic risk vs. those with attenuated psychotic symptoms, the former showed left anterior frontal, right caudate, as well as a smaller right hippocampus, and amygdala reduction, while the latter subgroup showed right middle temporal cortical reductions (each compared to healthy controls). Our findings in a clinical psychosis high-risk cohort demonstrate variability of brain structural changes according to subgroup and background of elevated risk, suggesting frontal and possibly also hippocampal/amygdala changes in individuals with genetic susceptibility. Heterogeneity of structural brain changes (as seen in schizophrenia) appears evident even at high-risk stage, prior to potential onset of psychosis.

Personality disorders (PD) belong to the most common and most serious mental disorders as regards social dysfunction, inability to work, occurrence of comorbidity and suicidal risk. PDs also crucially influence the incidence, clinical course and treatment response of mental disorders with high suicidal risk, such as depression or substance abuse. One key issue of PD concerns the regulation of emotions.BothOverall comparison including Bonferroni correction revealed significant differences of Glu across all groups in the dorsolateral prefrontal cortex (DLPFC). The following uncorrected results of pairwise tests were obtained: (i) Glu was bilaterally increased in the DLPFC in CB patients, whereas it was - together with NAA - bilaterally decreased in the DLPFC in CC patients and accompanied by increased PCr in the left DLPFC. (ii) NAA and Glu, accompanied by increased PCr, were significantly decreased in the dorsomedial prefrontal cortex (DMPFC) in CC patients. (iii) NAA was decreased in the right anterior cingulate cortex (ACC) in CB patients, and in the left ACC in CC patients with PCr being increased bilaterally. (iv) No associations were observed between metabolites and psychopathology measures.The observations in the DLPFC may reflect a neurobiochemical correlate of disturbed cognitive control function in CB and CC PD. While the alterations in CB patients suggest increased basal activity, the observed patterns in CC patients likely reflect decreased or inhibited activity. The alterations of NAA and Glu levels in the ACC and DMPFC indirectly support the assumption of disturbed neuronal function in regions involved in social cognition and mentalizing abilities in both CB and CC PD. Further studies should include the investigation of metabolites of neuronal inhibition (GABA) and the examination of treatment effects.

Measurements of exercise-induced metabolic changes, such as oxygen consumption, carbon dioxide exhalation or lactate concentration, are important indicators for assessing the current performance level of athletes in training science. With exercise-limiting metabolic processes occurring in loaded muscles

Hippocampal structural and functional integrity impacts on multiple remote areas of the brain, and this connectivity is central to multiple cognitive functions in healthy and disease. We studied associations of hippocampal metabolic markers N-acetyl aspartate (NAA) and glutamate (Glu and Glx; assessed with 1H magnetic resonance spectroscopy) and brain grey matter (studied with voxel-based morphometry, VBM) in 20 healthy subjects. We found a significant correlation between right hippocampal NAA and left ventrolateral prefrontal cortical grey matter (TFCE, p

Phase and frequency corrections of magnetic resonance spectroscopic data are of major importance to obtain reliable and unambiguous metabolite estimates as validated in recent research for single-shot scans with the same spectral fingerprint. However, when using the J-difference editing technique

Exercise-induced changes of transverse proton relaxation time (T2), tissue perfusion and metabolic turnover were investigated in the lower back muscles of volunteers by applying muscle functional MRI (mfMRI) and diffusion-weighted imaging (DWI) before and after as well as dynamic 31P-MRS during the exercise. Inner (M. multifidus, MF) and outer lower back muscles (M. erector spinae, ES) were examined in 14 healthy young men performing a sustained isometric trunk-extension. Significant phosphocreatine (PCr) depletions ranging from 30% (ES) to 34% (MF) and Pi accumulations between 95% (left ES) and 120%–140% (MF muscles and right ES) were observed during the exercise, which were accompanied by significantly decreased pH values in all muscles (∆pH ≈ –0.05). Baseline T2 values were similar across all investigated muscles (approximately 27 ms at 3 T), but revealed right–left asymmetric increases (T2,inc) after the exercise (right ES/MF: T2,inc = 11.8/9.7%; left ES/MF: T2,inc = 4.6/8.9%). Analyzed muscles also showed load-induced increases in molecular diffusion D (p = .007) and perfusion fraction f (p = .002). The latter parameter was significantly higher in the MF than in the ES muscles both at rest and post exercise. Changes in PCr (p = .03), diffusion (p

Background Glutamatergic dysfunction, deregulated mitochondrial metabolism and alterations of membrane phospholipids are considered as core pathology of psychosis, and have been studied in schizophrenic illness using magnetic resonance spectroscopy (MRS). Combining 1H- and 31P-MRS, this study investigates these aspects in Ultra-high risk (UHR-T) patients right after transition to psychosis (T0) and after a two years interval (T1) in a naturalistic longitudinal design, including treatment as usual by cognitive-behavioral therapy (CBT) and pharmacotherapy with second generation antipsychotics. Methods We applied 3 T chemical shift imaging (3D 31P-MRS, 2D 1H-MRS) and hippocampal single-voxel 1H-MRS in 29 neuroleptic-naïve UHR-T patients and 27 healthy controls matched for age and gender. Glutamate (Glu) and N-acetyl-aspartate (NAA) reflect neuronal functioning, phosphocreatine (PCr), adenosine triphosphate (ATP) and NAA indicate mitochondrial function and energy metabolism, and phosphomono- and diester indicate the balance of phospholipid synthesis (PME) and -breakdown (PDE). Psychopathology was assessed using the CAARMS, BPRS-E and SCL-90-R. Generalized linear mixed models were used to examine case-control differences in metabolite changes over time, and associations with clinical improvement. Results At T0, cross-sectional analysis revealed decreased NAA, Glu and PME levels in the left dorsolateral prefrontal cortex (DLPFC) and thalamus of UHR-T patients as well as higher PCr and lower PDE levels in the right hippocampus. (ii) Follow-up analysis (T1) showed in patients a significant increase of Glu in the bilateral DLPFC and the right thalamus, while a decrease of PCr was observed in the right hippocampus. Discussion The observed metabolite pattern at T0 likely reflects a hypofunction of glutamatergic neurons and a disturbance of membrane phospholipid turnover in fronto-thalamo-hippocampal networks during the first acute onset phase of psychotic illness. The pattern of changes at T1 is suggestive for an improvement of neuronal functioning in these networks that is caused by therapy, and presumably underlies the observed clinical improvement in terms of negative symptoms and cognitive impairment.

Background Oxidative stress and impaired antioxidant defense are reported in schizophrenia and are thought to be associated with disturbed neurodevelopment, brain structural alterations, glutamatergic imbalance, negative symptomatology, and cognitive impairment. To test some of these assumptions we investigated the glutathione (GSH) antioxidant defense system (AODS) and brain structural abnormalities in drug-naive individuals with first acute episode of psychosis (FEP). Method The study involved 27 drug-naive FEP patients and 31 healthy controls (HC). GSH AODS markers and TBARS (thiobarbituric acid reactive substances) were measured in blood plasma and erythrocytes. High-resolution T1-weighted 3T MRI were acquired from all subjects. To investigate brain structural abnormalities and effects of illness on interactions between GSH metabolites or enzyme activities and local grey matter density, voxel-based morphometry (VBM) with the computational anatomy toolbox (CAT12) was used. Symptomatology was assessed using the Positive and Negative Syndrome Scale (PANSS) and the Symptom Checklist 1990 revised (SCL-90-R). Results (i) In FEP patients, glutathione reductase activity (GSR) was lower than in the HC group. GSR activity in plasma was inversely correlated with SCL-90-R scores of depression and PANSS scores of the negative symptom subscale. (ii) A reduction of GM was observed in left inferior frontal, bilateral temporal, as well as parietal cortices of FEP patients. (iii) Interaction analyses revealed an influence of illness on GSR/GM associations in the left orbitofrontal cortex (BA 47). Conclusion Our findings support the notion of altered GSH antioxidative defense in untreated acute psychosis as a potential pathomechanism for localized brain structural abnormalities. This pathology relates to a key brain region of social cognition, affective motivation control and decision making, and is clinically accompanied by depressive and negative symptoms.

The aim of the study was to examine pH heterogeneity during fatigue induced by neuromuscular electrical stimulation (NMES) using phosphorus magnetic resonance spectroscopy (The medial gastrocnemius of eight subjects was stimulated within a 3-Tesla whole body MRI scanner. The maximal force during stimulation (FDuring fatigue, FIt is suggested that NMES is able to induce pH heterogeneity in the medial gastrocnemius, and that the single Pi peaks represent the different muscle fiber types of the skeletal muscle. Magn Reson Med 77:2097-2106, 2017. © 2016 International Society for Magnetic Resonance in Medicine.

Referencing metabolite intensities to the tissue water intensity is commonly applied to determine metabolite concentrations from in vivo (1)H-MRS brain data. However, since the water concentration and relaxation properties differ between grey matter, white matter and cerebrospinal fluid (CSF), the volume fractions of these compartments have to be considered in MRS voxels.The impact of partial volume correction was validated by phantom measurements in voxels containing mixtures of solutions with different NAA and water concentrations as well as by analyzing in vivo (1)H-MRS brain data acquired with various voxel compositions.Phantom measurements indicated substantial underestimation of NAA concentrations when assuming homogeneously composed voxels, especially for voxels containing solution, which simulated CSF (error: ≤ 92%). This bias was substantially reduced by taking into account voxel composition (error: ≤ 10%). In the in vivo study, tissue correction reduced the overall variation of quantified metabolites by up to 35% and revealed the expected metabolic differences between various brain tissues.Tissue composition affects extraction of metabolite concentrations and may cause misinterpretations when comparing measurements performed with different voxel sizes. This variation can be reduced by considering the different tissue types by means of combined analysis of spectroscopic and imaging data.

Choline (Cho) signal identification and quantification in 1H MRS are used in breast cancer diagnosis. However, an influence of the gadolinium-based contrast agent on the Cho amplitude has been reported experimentally. This study aims to identify the impact of gadolinium-based contrast agents on Cho detection and quantification in postcontrast breast MRS. Consecutive patients were recruited prospectively and randomly allocated to two groups. Group A received a neutral (gadolinium diethylenetriaminepentaacetic acid bis-methylamide) and group B an ionic (gadolinium diethylenetriaminepentaacetic acid) contrast agent, each at a dosage of 0.1 mmol/kg. First, the presence of Cho was identified visually. Then, the normalized Cho intensity in malignant lesions was quantified. Multivariate analysis was applied to identify independent influencing factors on Cho. Sixty-three lesions were investigated [A, n = 34; B, n = 29; 43 malignant (one bilaterally malignant), 20 benign]. Cho was identified visually in 14 of 20 malignant tumors in group A and 12 of 22 malignant tumors in group B (p = 0.477). Normalized Cho differed significantly (p = 0.001) between groups A (mean, 26.8 ± 6.0 AU) and B (mean, 18.2 ± 12.5 AU). No linewidth differences were identified (p > 0.05). Multivariate analysis revealed only group membership (A versus B) as an independent predictor of Cho (p = 0.017). The results suggest stronger negative effects of an ionic relative to a neutral gadolinium-based contrast agent on breast tumor MRS in vivo. These results should be considered when conducting and comparing quantitative Cho measurements in the breast. Copyright © 2011 John Wiley & Sons, Ltd.

Background Glutamatergic dysfunction, deregulated mitochondrial metabolism and alterations of membrane phospholipids have been extensively investigated in schizophrenic illness by using in vivo magnetic resonance spectroscopy (MRS). Findings in the ultra-high risk (UHR) phase of psychotic illness, however, are still rare and inconsistent. Combining both 1H- and 31P-MRS, this study investigates these aspects in the different UHR patient subgroups as defined by PACE (Personal Assessment and Crisis Evaluation) criteria. Methods We applied 3 T chemical shift imaging (3D 31P-MRS, 2D 1H-MRS) and hippocampal single-voxel MRS in 69 neuroleptic-naïve UHR patients (age: 26.2 ± 6.2y; males 59.4% 41/69, attenuated symptoms (AS) n=50, BLIPS n=5, genetic risk (GR) n=8, AS+GR n=6; transition rate 17.2%, all transitions in the AS or BLIPS group) and 61 healthy controls (age: 25.2 ± 4.8y; males 54.1% 33/61). 11 metabolite markers were investigated (neuronal/mitochondrial metabolism: glutamate (Glu), N-acetyl-aspartate (NAA), phosphocreatine (PCr), and adenosine triphosphate (ATP); phospholipid synthesis: phosphomonoester/-metabolites (PME, Peth, Pch); phospholipids breakdown: phosphodiester/-metabolites (PDE, Gpeth, Gpch); astrocyte activation: myo-Inositol (mI)) in 5 brain regions (dorsolateral prefrontal cortex, DLPFC; dorsomedial prefrontal cortex, DMPFC; dorsal anterior cingulate cortex, dACC; mediodorsal thalamus, Th; and hipoocampus, Hip). Psychopathology was assessed using the CAARMS-Interview as well as PANSS, BPRS-E and SCL-90-R ratings. Statistical analysis included multi-and univariate ANOVA, Kruskal-Wallis-tests and correlation analysis. Results (i) In all UHR individuals (and also in the AS and BLIPS subgroup), NAA was reduced in the left Th. There was no alteration of Glu. While PCr was increased in the left DLPFC, left dACC (right trend) and in the right Hip, ATP was not different from controls. PME were decreased in the right Hip, PDE did not differ from controls. mI was found increased in the left Hip. (ii) In the GR subgroup PCr was increased in the bilateral Th. The PME metabolite Peth was decreased in the right Th. PDE were increased in the left dACC. mI was increased in the left Th. Discussion While the observed pattern of metabolite abnormalities in the AS and BLIPS risk group suggests a pathology that affects the left thalamus (NAA decrease), left DLPFC, dACC and bilateral Hip (left: PCr increase, PME decrease; right mI increase), the pathology of the GR group appears more focussed on the bilateral Th (bil. PCr increase, right PME decrease, left mI increase) and left dACC (PDE increase). The results suggest a functional disturbance of networks including the left DLPFC, dACC, bilateral Hip and Th, whereby the latter might be more an expression of a genetic risk profile.

Measurements of exercise-induced metabolic changes, such as oxygen consumption, carbon dioxide exhalation or lactate concentration, are important indicators for assessing the current performance level of athletes in training science. With exercise-limiting metabolic processes occurring in loaded muscles, 31 P-MRS represents a particularly powerful modality to identify and analyze corresponding training-induced alterations. Against this background, the current study aimed to analyze metabolic adaptations after an exhaustive exercise in two calf muscles (m. soleus - SOL - and m. gastrocnemius medialis - GM) of sprinters and endurance athletes by using localized dynamic 31 P-MRS. In addition, the respiratory parameters VO2 and VCO2 , as well as blood lactate concentrations, were monitored simultaneously to assess the effects of local metabolic adjustments in the loaded muscles on global physiological parameters. Besides noting obvious differences between the SOL and the GM muscles, we were also able to identify distinct physiological strategies in dealing with the exhaustive exercise by recruiting two athlete groups with opposing metabolic profiles. Endurance athletes tended to use the aerobic pathway in the metabolism of glucose, whereas sprinters produced a significantly higher peak concentration of lactate. These global findings go along with locally measured differences, especially in the main performer GM, with sprinters revealing a higher degree of acidification at the end of exercise (pH 6.29 ± 0.20 vs. 6.57 ± 0.21). Endurance athletes were able to partially recover their PCr stores during the exhaustive exercise and seemed to distribute their metabolic activity more consistently over both investigated muscles. In contrast, sprinters mainly stressed Type II muscle fibers, which corresponds more to their training orientation preferring the glycolytic energy supply pathway. In conclusion, we were able to analyze the relation between specific local metabolic processes in loaded muscles and typical global adaptation parameters, conventionally used to monitor the training status of athletes, in two cohorts with different sports orientations.

PURPOSE: The influence of different magnetic field strengths on the quantification of glutamate was experimentally investigated by means of IN VITRO and IN VIVO 1 H-MR spectroscopic measurements at 1.5 T and 3 T. MATERIALS AND METHODS: In vitro 1 H-MR measurements of aqueous solutions of NAA, glutamate, glutamine and GABA were performed on two clinical MR scanners at 1.5 T and 3 T using a single voxel PRESS sequence (TR/TE = 10 000 / 30 ms). IN VITRO brain measurements were also performed at both field strengths using a PRESS 2D- 1 H-CSI-sequence (TR/TE = 5000 / 30 ms) in 6 volunteers. Spectra at 1.5 T and 3 T were compared with respect to the overlap of the single compound spectra and the deviations between estimated and nominally adjusted concentrations. In vivo spectra at both field strengths were compared with respect to SNR Glu , line width and Cramer-Rao values of the estimated glutamate intensities by using the LCModel. For the thalamus, insular and parietal cortex mean Glu/tCr ratios were estimated and compared between 1.5 T and 3 T as well as with corresponding values in the literature. RESULTS: In general, an improved separation of signal maxima was observed in the IN VITRO spectra at 3 T. Except for GABA, all IN VITRO concentrations estimated at 3 T revealed lower deviations from their adjusted nominal concentration compared to 1.5 T: NAA (1.5 T: -5.5 %, 3 T: 0.7 %), glutamate (1.5 T: -18.1 %, 3 T: 12.3 %), glutamine (1.5 T: 44.8 %, 3 T: 9.2 %), GABA (1.5 T: - 24.8 %, 3 T: 33.8 %). The SNR of IN VIVO spectra at 3 T was nearly doubled compared to 1.5 T. The mean number of voxels with %SD Glu < 20 was distinctly lower at 1.5 T (53 %) than at 3 T (80 %). Estimated Glu/tCr ratios for thalamus, insular and parietal cortex lay in the upper range of the literature values. CONCLUSION: The results indicate that the advantageous distribution of signal maxima at 3 T allows an improved separation of the individual spectra. Both the higher initial magnetization at 3 T and the improved sensitivity of the phased array matrix coil used in the 3 T study result in an increased SNR, which leads to better reliability of the individual detection as well as a more accurate quantification of glutamate.

Animal and human studies suggest differing anatomical and functional connectivity patterns of the anterior and posterior hippocampus. The biochemical underpinnings of the hippocampal resting state connectivity along this anterior-posterior axis remain unclear. We investigated twenty-five healthy male subjects in a multimodal study. We aimed to examine the relationship between resting state functional connectivity (RSFC) of the left and right hippocampus separated along the anterior-posterior axis and the corresponding glutamatergic function assessed by proton magnetic resonance spectroscopy ((1)H-MRS) of the glutamate-glutamine (Glx) complex. We observed a clear functional differentiation of the hippocampal RSFC along this axis. Moreover, a highly significant correlation was observed between the concentration of Glx in the right anterior hippocampus and its corresponding functional connectivity, but not with the amplitude of local low frequency fluctuations. Lower Glx levels were associated with a higher functional connectivity to the medial prefrontal cortex, perigenual anterior cingulate cortex (pACC) and the left ventrolateral prefrontal cortex (VLPFC). In addition, the Glx concentration in the posterior hippocampus predicted the verbal memory performance, i.e., the degree of retroactive interference. The present findings demonstrate for the first time a modulation of the anterior hippocampal RSFC by Glx concentration.

The objective of the study was to investigate the reproducibility of exercise induced pH-heterogeneity by splitting of the inorganic phosphate (Pi) signal in the correspondingSubjects (N=3) with different sportive background were tested in 10 test sessions separated by at least 3 days. A MR-compatible pedal ergometer was used to perform the exercise and to induce a pH-based splitting of the Pi-signal inThe reproducibility (standard deviation between measurements) based on (1) Pi components varied from 2% to 4%, (2) PCr recovery time components varied from 10% to 12% and (3) phosphate concentrations at rest varied from 8% to 11% between test sessions. Due to the sportive activity differences between the 3 subjects were expected in view of fiber type distribution. All estimated markers indicate the highest type I percentage for volunteer 3 medium for volunteer 2 and the lowest for volunteer 1.The relative high reproducibility of pH dependent Pi components during exercise indicates a high potential of this method to estimate muscle fiber-type distributions in vivo. To make this method usable not only to detect differences in muscle fiber distributions but also to determine individual fiber-type volume contents it is therefore recommended to validate this marker by histological methods and to reveal the effects of muscle fiber recruitments and fiber-type specific Pi concentrations on the intensity ratios between the splitted Pi-components.

Glutamatergic dysfunction and altered membrane lipid and energy metabolism have been repeatedly demonstrated in the frontal/prefrontal and anterior cingulate cortex (ACC) in schizophrenia. Though having been already studied in animals, the presumed link between glutamatergic function and structural plasticity has not been investigated directly in the human brain yet. We measured glutamate (Glu), focal energy metabolism, and membrane phospholipid turnover to investigate main pathologies in those key brain regions of schizophrenia.(1)H- and (31)P-Chemical Shift Imaging (CSI) was combined in a single session to assess Glu and markers of energy (PCr, ATP) and membrane lipid (PME, PDE) metabolism in 31 neuroleptic-naïve first acute onset psychosis patients and 31 matched healthy controls. Multivariate analyses of covariance were used to assess disease effects on Glu and to investigate the impact of Glu alterations on phospholipid and energy metabolites.Glu levels of patients were increased in the frontal and prefrontal cortex bilaterally and in the ACC. Higher Glu was associated with increased left frontal/prefrontal PME and right frontal/prefrontal PDE in patients, which was not observed in healthy controls. In contrast, higher Glu levels were associated with lower PCr or ATP values in the frontal/prefrontal cortex bilaterally and in the right ACC of controls. This was not observed in the right ACC and left frontal/prefrontal cortex of patients.Frontal glutamatergic hyperactivity is disconnected from physiologically regulated energy metabolism and is associated with increased membrane breakdown in right and increased membrane restoration in left frontal and prefrontal cortical regions. As indicated by previous findings, this pathology is likely dynamic during the course of first acute illness and possibly associated with negative symptoms and cognitive impairment. Our findings underline the importance of further research on neuroprotective treatment options during the early acute or even better for the ultra-high risk state of psychotic illness.

Antipsychotic drug action might include mechanisms related to normalising phospholipid and high-energy metabolism. We applied brain metabolic imaging with 31P magnetic resonance spectroscopy (31P MRS) and two-dimensional chemical shift imaging to assess changes of metabolism of phospholipids and high-energy phosphates in schizophrenia patients at baseline (four antipsychotic-naive and three off antipsychotics) and at follow-up, after 6 weeks of treatment with olanzapine. Results indicate a significant increase of adenosine-triphosphate (ATP) in the right inferior temporal cortex and a trend towards ATP decrease in the left cerebellum. This suggests a shift in high-energy phosphates (rather than phospholipids), possibly related to normalisation of functioning in these areas. Copyright © 2012 John Wiley & Sons, Ltd.

Simultaneous measurements of pulmonary oxygen consumption (VO2), carbon dioxide exhalation (VCO2) and phosphorus magnetic resonance spectroscopy (31P–MRS) are valuable in physiological studies to evaluate muscle metabolism during specific loads. Therefore, the aim of this study was to adapt a commercially available spirometric device to enable measurements of VO2 and VCO2 whilst simultaneously performing 31P–MRS at 3 T. Volunteers performed intense plantar flexion of their right calf muscle inside the MR scanner against a pneumatic MR-compatible pedal ergometer. The use of a non-magnetic pneumotachograph and extension of the sampling line from 3 m to 5 m to place the spirometric device outside the MR scanner room did not affect adversely the measurements of VO2 and VCO2. Response and delay times increased, on average, by at most 0.05 s and 0.79 s, respectively. Overall, we were able to demonstrate a feasible ventilation response (VO2 = 1.05 ± 0.31 L/min; VCO2 = 1.11 ± 0.33 L/min) during the exercise of a single calf muscle, as well as a good correlation between local energy metabolism and muscular acidification (τPCr fast and pH; R2 = 0.73, p < 0.005) and global respiration (τPCr fast and VO2; R2 = 0.55, p = 0.01). This provides improved insights into aerobic and anaerobic energy supply during strong muscular performances.

During aging declining maximum force capacity with more or less unchanged fatigability is observed with the underlying mechanisms still not fully understood. Therefore, we compared morphology and function of skeletal muscles between different age groups. Changes in high-energy phosphate turnover (PCr, Pi and pH) and muscle functional MRI (mfMRI) parameters, including proton transverse relaxation time (T 2 ), diffusion (D) and vascular volume fraction (f), were investigated in moderately exercised low back muscles of young and late-middle-aged healthy subjects with 31 P-MR spectroscopy, T 2 - and diffusion-weighted MRI at 3 T. In addition, T 1 -weighted MRI data were acquired to determine muscle cross-sectional areas (CSA) and to assess fat infiltration into muscle tissue. Except for pH, both age groups showed similar load-induced MR changes and rates of perceived exertion (RPE), which indicates comparable behavior of muscle activation at moderate loads. Changes of mfMRI parameters were significantly associated with RPE in both cohorts. Age-related differences were observed, with lower pH and higher Pi/ATP ratios as well as lower D and f values in the late-middle-aged subjects. These findings are ascribed to age-related changes of fiber type composition, fiber size and vascularity. Interestingly, post exercise f was negatively associated with fat infiltration with the latter being significantly higher in late-middle-aged subjects. CSA of low back muscles remained unchanged, while CSA of inner back muscle as well as mean T 2 at rest were associated with maximum force capacity. Overall, applying the proposed MR approach provides evidence of age-related changes in several muscle tissue characteristics and gives new insights into the physiological processes that take place during aging.

In vivo(1)H MR spectroscopic detection of pain associated metabolic changes in the human brain may allow for an objective evaluation of the perceived pain intensity and assessment of the involved neurotransmitters. Ultimately, it may lead to a deeper understanding of the mechanisms that underlie neuronal pain processing. The present study reports results of time-resolved measurements of acute heat pain induced changes of the excitatory (Glx) and inhibitory (GABA+) neurotransmitter turnover in the anterior cingulate cortex (ACC) and occipital cortex (OC) by using (1)H MEGA-PRESS spectroscopy. In ACC and OC, the ratio Glx/tCr increased by median values of 21.5% (p < 0.001) and 15.7% (p < 0.001), respectively. At the same time, GABA+/tCr decreased by median values of 15.1% (p = 0.114) in ACC and 12.7% (p < 0.001) in OC. To our knowledge, this study demonstrates for the first time the possibility of quantifying pain-induced neurotransmitter changes in the brain by using functional (1)H MEGA-PRESS. The increase of Glx/tCr may be ascribed to an elevated glutamatergic turnover, while the decrease of GABA+/tCr may reflect reduced activity of the inhibitory system in ACC and OC during pain processing.

Exercise-induced changes of transverse proton relaxation time (T2 ), tissue perfusion and metabolic turnover were investigated in the lower back muscles of volunteers by applying muscle functional MRI (mfMRI) and diffusion-weighted imaging (DWI) before and after as well as dynamic (31) P-MRS during the exercise. Inner (M. multifidus, MF) and outer lower back muscles (M. erector spinae, ES) were examined in 14 healthy young men performing a sustained isometric trunk-extension. Significant phosphocreatine (PCr) depletions ranging from 30% (ES) to 34% (MF) and Pi accumulations between 95% (left ES) and 120%-140% (MF muscles and right ES) were observed during the exercise, which were accompanied by significantly decreased pH values in all muscles (∆pH ≈ -0.05). Baseline T2 values were similar across all investigated muscles (approximately 27 ms at 3 T), but revealed right-left asymmetric increases (T2 ,inc ) after the exercise (right ES/MF: T2 ,inc = 11.8/9.7%; left ES/MF: T2 ,inc = 4.6/8.9%). Analyzed muscles also showed load-induced increases in molecular diffusion D (p = .007) and perfusion fraction f (p = .002). The latter parameter was significantly higher in the MF than in the ES muscles both at rest and post exercise. Changes in PCr (p = .03), diffusion (p .01) and perfusion (p = .03) were strongly associated with T2,inc , and linear mixed model analysis revealed that changes in PCr and perfusion both affect T2,inc (p .001). These findings support previous assumptions that T2 changes are not only an intra-cellular phenomenon resulting from metabolic stress but are also affected by increased perfusion in loaded muscles.

Purpose Chronic pain is in many cases associated with a poor quality of life and high health care costs. Due to the multimodal disease origin, therapeutic methods are often rather unspecific. By applying modern functional imaging methods, neuronal dysfunction has been recently identified in patients and has been hypothesized to reflect the disease related central sensitization of neuronal pain processing (Farmer, 2012). However, the underlying neurochemical processes, especially changes in neurotransmitter turnover, remain widely unexplored although their understanding might be essential to improve current therapeutic approaches (Borsook, 2007). 1 H-MR spectroscopy allows in vivo quantitation of glutamate and GABA, which are two of the most important neurotransmitters, and provides direct insight into chronic pain related neurochemical changes (Harris, 2012). In the present study, GABA and glutamate were quantified in three different pain processing regions of the brain of patients with unspecific chronic low back pain and compared to healthy subjects in order to investigate potentially altered regional and interregional neurochemical interrelations. Methods 13 patients (12f/1m) and 13 age and gender matched healthy subjects (54±8years) participated in this study. Patients underwent detailed clinical evaluation to assess their chronic pain state and adjacent effects. All measurements were performed with a whole-body 3T MR scanner (Siemens, Germany). Conventional and spectrally edited 1 H-MR spectra were collected from the anterior cingulate cortex (aCC), left insula (Ins) and posterior cortex (PC) with a PRESS sequence (TR/TE: 1800/30ms) and a MEGAPRESS sequence (TR/TE: 1800/68ms), respectively (Fig. 1). Sum intensities of glutamate and glutamine (Glx) were quantified from conventional spectra by using the LCModel (Provencher, 1993), whereas the GABA intensities were determined from the edited spectra with the jMRUI package (Stefan, 2009). Afterwards, all intensities were normalized with the corresponding creatine intensity. Regional and interregional interrelations were determined by means of Pearson correlations between GABA and Glx within as well as between the examined brain regions and compared between the two groups. Results and discussion Fig. 1 shows the correlation matrix with significant ( p

A pneumatic MR-compatible pedal ergometer was designed to perform dynamic contraction exercises of the human calf muscle in a whole-body 3T MR scanner. The set-up includes sensors for monitoring mechanical parameters, such as pedal angle, cadence as well as applied force and power. Actual parameter values during the exercise were presented to the volunteer as a visual feedback to enable real-time self-adjustment of pedal deflection and cadence to the target reference value. Time-resolved dynamic 31 P-MR spectroscopic measurements of phosphocreatine (PCr), inorganic phosphate (Pi) and pH were performed in a pilot experiment before, during, and after the exercise by a single volunteer. Two different load strengths were applied in these experiments (15% and 25% of the maximum voluntary contraction, MVC). As expected, mechanical and metabolic parameters differed for the two load levels. Small variations of the cadence, power and metabolic changes (time constants of PCr depletion and Pi accumulation) during the experiments demonstrate a highly reproducible mechanical output by the volunteer mediated by the ergometer.

Structural deficits in the superior temporal cortex and transverse temporal gyri appear to be related to auditory hallucinations in schizophrenia, which are a key symptom of this disorder. However, the cellular and neurochemical underpinnings are poorly understood and hardly studied in vivo. We used (31)P-MRS (magnetic resonance spectroscopy) with chemical shift imaging to assess the association between left superior temporal cortex metabolism and severity of auditory hallucinations in 29 schizophrenia patients off antipsychotics. Hallucinations scores derived from the Scale for the Assessment of Positive Symptoms showed significant positive correlations with both measures of phospholipids (phosphomonoesters and phosphodiesters), and energy (inorganic phosphate and phosphocreatine, but not adenosine tri-phosphate) metabolism in left superior temporal gyrus/Heschl gyrus voxels. There was no correlation of metabolites in these regions with formal thought disorder, a symptom also linked to superior temporal pathology, thus suggesting symptom specificity. Our findings provide a link between established structural deficits and neurochemical pathology related to membrane pathology and markers of general metabolic turnover.