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In a multisite study of brain MR spectroscopy performed at 26 sites, interindividual differences were found as the main contributor to variability, demonstrating that appropriately analyzed MR spectroscopy data acquired at different sites and with different scanners can be compared.

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Gadolinium concentration was significantly higher in subjects who received prior gadolinium-based contrast agents (GBCAs) than in control subjects, and there was a positive correlation between the administered GBCA dose and the gadolinium concentration measured in bone.

Myofascial pain syndrome is one of the most common causes of chronic pain and is highlighted by the presence of myofascial trigger points. The current practice of diagnosing myofascial pain syndrome among clinicians involves manual detection of myofascial trigger points, which can be inconsistent. However, the detection process can be strengthened with the assistance of ultrasound (US). Therefore, this study aimed to characterize the upper trapezius by using quantitative techniques in healthy asymptomatic individuals with neck pain. Study participants were recruited on the basis of the inclusion and exclusion criteria established, and US images of the trapezius, along the axial and longitudinal orientations, were obtained. Each set was obtained by 2 investigators: experienced and inexperienced personnel. Fifteen participants were recruited. The mean gray scale US echo intensity distribution obtained was 41.9. A paired ttest of the global mean echo intensity value obtained for each image from the US operators did not show any significant difference (P= .77). A ttest was performed, comparing the echo intensity of the group of patients with neck pain and healthy control participants, and the difference was found to be significant (P= .052). The median blob area was 2.71. The quartile range for the blob area was 1.72 for the 25th percentile to 4.90 for the 75th percentile. This study demonstrated that quantitative analysis of the echo intensity of US images can provide important information. However, further research is necessary to explore the relationships among sex, age, blob area, count, body mass index, regional anatomy, and extent of training or exercise of the particular muscle.

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•Molecular and genetic changes influence mTBI severity and recovery.•Genotype and post-mTBI epigenetics are major recovery determinants.•mTBI-specific genetic polymorphisms can be utilized to predict recovery.•Polymorphism of crucial neuronal genes can be detrimental to mTBI recovery.•Features and substantial CNS influence make miRNA reliable mTBI biomarkers.

Exercise intolerance is prevalent in individuals with Turner Syndrome (TS). We recently demonstrated that girls with TS have normal aerobic but altered skeletal muscle anaerobic metabolism compared to healthy controls (HC). The purpose of this study was to compare peripheral skeletal muscle microvascular function in girls with TS to HC after exercise. We hypothesized that girls with TS would have similar muscle blood-oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) signal responses during recovery from exercise compared to HC.

•Advanced MRI scans can detect long-term concussion-related brain damage.•Repetitive concussive events can result in lasting functional brain abnormalities.•Minimal microstructural damage was detected in the aging, retired athletes.•Pre-motor cortex, hippocampus dentate gyrus and visual cortex were commonly injured.•Impaired social functioning, emotional well-being, energy, and general health.

•Routine clinical MRI scans can detect early signs of Parkinsonian Syndromes.•MRI is able to differentiate idiopathic Parkinson's Disease from Parkinsonian Syndromes.•Newer MRI techniques, such as Quantitative Susceptibility Mapping (qSM) and Chemical Exchange Saturation Transfer (CEST), show promise for earlier diagnosis.•Nuclear medicine techniques, such as Positron Emission Tomography (PET) and Single Photon Emission Computed Tomography (SPECT), have higher sensitivity than MRI.•PET and SPECT are currently used more in research and will in the future, when specificity is understood more, will be more clinically performed.

Previous studies have reported differences in muscle function and metabolism between patients with cystic fibrosis (CF) and healthy controls (HC), but it is currently unknown whether these abnormalities are specific to CF or also seen in other airway diseases. In this study, we used magnetic resonance spectroscopy (MRS) during exercise to assess muscle metabolism in CF patients. Twenty patients with CF and 20 age, gender, and habitual activity-matched HCs and a respiratory disease comparison group with primary ciliary dyskinesia (PCD; n = 10) were studied. 31Phosphorus MRS (31P-MRS) was used to characterize muscle bioenergetic metabolism at rest and after high-, moderate-, and low-intensity exercise. CF patients exhibited lower resting ATP/phosphocreatine (PCr) ratio and significantly higher end-exercise pH values compared with both HC and PCD patients. Both CF and PCD patients demonstrated significantly slower PCr recovery time constants after high-intensity exercise. Our results suggest that not only there are specific abnormalities of muscle metabolism in CF patients but also there is a nonspecific impact of respiratory disease on muscle function.

Previous studies have reported differences in muscle function and metabolism between patients with cystic fibrosis (CF) and healthy controls (HC), but it is currently unknown whether these abnormalities are specific to CF or also seen in other airway diseases. In this study, we used magnetic resonance spectroscopy (MRS) during exercise to assess muscle metabolism in CF patients. Twenty patients with CF and 20 age, gender, and habitual activity-matched HCs and a respiratory disease comparison group with primary ciliary dyskinesia (PCD; n10) were studied. 31Phosphorus MRS (31P-MRS) was used to characterize muscle bioenergetic metabolism at rest and after high-, moderate-, and low-intensity exercise. CF patients exhibited lower resting ATP/phosphocreatine (PCr) ratio and significantly higher end-exercise pH values compared with both HC and PCD patients. Both CF and PCD patients demonstrated significantly slower PCr recovery time constants after high-intensity exercise. Our results suggest that not only there are specific abnormalities of muscle metabolism in CF patients but also there is a nonspecific impact of respiratory disease on muscle function.

To compare diffusion tensor-magnetic resonance imaging (DT-MRI) of human calf muscles at 1.5 T and 3.0 T, and to measure a number of quantitative parameters to characterize diffusion anisotropy in organized muscle tissue using similar imaging parameters.

Blood-oxygen-level-dependent (BOLD) imaging was a concept introduced in 1990 for evaluating brain activation. The method relies on magnetic resonance imaging (MRI) contrast resulting from changes in the microvascular ratio of oxyhaemoglobin (oxyHb) to deoxyhaemoglobin (deoxyHb). OxyHb is diamagnetic, whereas deoxyHb is paramagnetic, which produces a local bulk magnetic susceptibility effect and subsequent MRI signal change. The changes are typically observed in T2*-weighted functional MRI scans. However, there has recently been interest in BOLD as a way to evaluate microcirculation of any normal or diseased tissue. This review focuses on the application of BOLD imaging in the understanding of normal and diseased skeletal muscle. In addition we present new findings showing the possible application of BOLD imaging with hyperoxia for evaluating skeletal muscle physiology.

Using dynamic Magnetic Resonance Imaging (dMRI), blood-brain barrier (BBB) permeability (kPSp) and tissue interstitial leakage space (ve) were evaluated in zinc-deficient (ZnDF) male weanling Wistar rats following 3 days exposure to hyperoxia (85% O2). Temporal monitoring of T1-weighted MR image changes, following a bolus intravenous injection of gadolinium-DTPA, allowed estimation of BBB integrity. Three-day exposure of hyperoxia caused a marginal loss of BBB integrity, reflected in a slight increase in kPSpand ve, observed in both the animals fed adequate zinc (ZnAL) and pair-fed controls (ZnPF). However, zinc deficiency resulted in a significant increase in both kPSpand ve, indicating a severely disturbed BBB. In addition MR-visible free water was elevated in ZnDF brains following hyperoxia treatment indicating that a loss of BBB integrity may be associated with neuronal edema. The diminished BBB integrity may be free-radical mediated as the ratio of oxidized to reduced glutathione (GSSG:GSH) was significantly elevated.

In rodents, lower brown adipose tissue (BAT) activity is associated with greater liver steatosis and changes in the gut microbiome. However, little is known about these relationships in humans. In adults (n = 60), we assessed hepatic fat and cold-stimulated BAT activity using magnetic resonance imaging and the gut microbiota with 16S sequencing. We transplanted gnotobiotic mice with feces from humans to assess the transferability of BAT activity through the microbiota. Individuals with NAFLD (n = 29) have lower BAT activity than those without, and BAT activity is inversely related to hepatic fat content. BAT activity is not related to the characteristics of the fecal microbiota and is not transmissible through fecal transplantation to mice. Thus, low BAT activity is associated with higher hepatic fat accumulation in human adults, but this does not appear to have been mediated through the gut microbiota.

Blood and muscle T1and T2relaxivity was examined under normoxic (air; 20.8% O2) and hyperoxic (100% O2) conditions to determine whether the oxygenation state of blood in the large vessels and in the microcirculation can be monitored in vivo. The femoral artery/vein and the soleus and gastrocnemius muscles were examined in healthy human male volunteers. Arterial blood T1decreased with hyperoxia, while venous blood T2increased, due to increased dissolved O2and decreased deoxyhemoglobin, respectively. A biexponential T2model of muscle is proposed, where the short T2component reflects primarily the intracellular and interstitial compartments (in fast exchange), and the long T2reflects blood. In this model, the long T2component increased with hyperoxia exposure. This was more evident in slow twitch (soleus) than in fast twitch (gastrocnemius) muscle. It is concluded that changes in the long T2component reflect change in the microcirculation oxygenation state. J. Magn. Reson. Imaging 1999;9:814–820. © 1999 Wiley‐Liss, Inc.

Blood and muscle T1 and T2 relaxivity was examined under normoxic (air; 20.8% O2) and hyperoxic (100% O2) conditions to determine whether the oxygenation state of blood in the large vessels and in the microcirculation can be monitored in vivo. The femoral artery/vein and the soleus and gastrocnemius muscles were examined in healthy human male volunteers. Arterial blood T1 decreased with hyperoxia, while venous blood T2 increased, due to increased dissolved O2 and decreased deoxyhemoglobin, respectively. A biexponential T2 model of muscle is proposed, where the short T2 component reflects primarily the intracellular and interstitial compartments (in fast exchange), and the long T2 reflects blood. In this model, the long T2 component increased with hyperoxia exposure. This was more evident in slow twitch (soleus) than in fast twitch (gastrocnemius) muscle. It is concluded that changes in the long T2 component reflect change in the microcirculation oxygenation state. J. Magn. Reson. Imaging 1999;9:814–820. © 1999 Wiley-Liss, Inc.