MRI Technology Research Articles

Dynamic glucose-enhanced MRI of gliomas: A preliminary clinical application.

The study aimed to investigate the feasibility of dynamic glucose-enhanced (DGE) MRI technology in the clinical application of glioma. Twenty patients with glioma were examined using a preoperative DGE-MRI protocol before clinical intervention. A brief hyperglycemic state was achieved by injecting 50 mL of 50% w/w D-glucose intravenously during the DGE imaging. The total acquisition time for the DGE was 15 min. Area-under-the-curve (AUC) images were calculated using the DGE images. AUC2-7min values of the glioma core, margin area, edema area, and contralateral brain parenchyma were compared using Mann-Whitney U tests. Overall, gray and white matter areas in the AUC images showed relatively low DGE signal change and bilateral symmetry. However, the tumor cores displayed a significant hyperintensity. A high DGE signal change was also seen in the necrotic, cystic, and cerebrospinal areas. These results show that DGE MRI is a feasible technique for the study of brain tumors as part of a clinical exam. Importantly, DGE MRI showed enhancement in areas confirmed histopathologically as tumors, whereas Gd T1w MRI did not show any enhancement in this area. Since the D-glucose molecule is smaller than Gd-based contrast agents, DGE MRI may be more sensitive to subtle blood-brain barrier disruptions, thus potentially providing early information about possible malignancy. These findings provide a new perspective for the further exploration and analysis of D-glucose uptake in brain tumors.

Practical approach to diagnose and manage benign liver masses.

Benign liver lesions are among the most commonly diagnosed abnormalities in liver imaging. They are often discovered incidentally during routine examinations or imaging conducted for unrelated reasons. These can be solid lesions, such as hemangiomas, focal nodular hyperplasia, hepatic adenomas, or cystic lesions. Recent advancements in MRI technology, particularly with hepatocyte-specific contrast agents, have enhanced the characterization of these lesions, reducing the reliance on invasive tissue sampling. Nevertheless, tissue sampling retains a crucial role in the evaluation of indeterminate lesions or those with malignant potential. While most benign liver lesions are asymptomatic, some can become symptomatic, causing discomfort, pain, or bleeding, particularly if the lesion is large. A deep understanding of the molecular underpinnings of the lesions is crucial for tailoring patient management strategies, particularly in distinguishing lesions that require surgical intervention from those that can be monitored. For instance, the molecular subclassification of hepatic adenomas has provided mechanistic insights and identified certain subtypes that are at higher risk of malignancy. Most benign liver lesions can be safely monitored; however, in patients with cirrhosis or a known primary malignancy, a high index of suspicion for cancer is required. It is crucial to carefully evaluate any liver lesion identified in these patients to ensure that indeterminate lesions are not overlooked. Effective management of benign liver lesions involves a multidisciplinary team, including hepatologists, surgeons, and radiologists, ensuring a comprehensive and individualized approach to patient care. This review outlines the clinical presentation of common benign liver lesions, providing a diagnostic and management framework. Emphasis is placed on a personalized approach to minimize patient distress and optimize outcomes by leveraging imaging advancements and multidisciplinary collaboration.

Quantitative MRI in Childhood Neuroblastoma: Beyond the Assessment of Image-defined Risk Factors.

Neuroblastoma commonly occurs in children. MRI is a radiation-free imaging modality and has played an important role in identifying image-defined risk factors of neuroblastoma, providing necessary guidance for surgical resection and treatment response evaluation. However, image-defined risk factors are limited to providing structural information about neuroblastoma. With the evolution of MRI technologies, quantitative MRI can not only help assess image-defined risk factors but can also quantitatively reflect the biologic features of neuroblastoma in a noninvasive manner. Therefore, compared with anatomic imaging, these emerging quantitative MRI technologies are expected to provide more imaging biomarkers for the management of neuroblastoma. This review article discusses the current applications of quantitative MRI technologies in evaluating childhood neuroblastoma. Keywords: Pediatrics, MR-Functional Imaging, Children, MRI, Neuroblastoma, Quantitative Imaging © RSNA, 2024.

Field cycling imaging to characterise breast cancer at low and ultra-low magnetic fields below 0.2 T

BackgroundThis prospective feasibility study explores Field-Cycling Imaging (FCI), a new MRI technology that measures the longitudinal relaxation time across a range of low magnetic field strengths, providing additional information about the molecular properties of tissues. This study aims to assess the performance of FCI and investigate new quantitative biomarkers at low fields within the context of breast cancer.MethodsWe conducted a study involving 9 people living with breast cancer (10 tumours in total, mean age, 54 ± 10 years). FCI images were obtained at four magnetic field strengths (2.3 mT to 200 mT). FCI images were processed to generate T1 maps and 1/T1 dispersion profiles from regions of tumour, normal adipose tissue, and glandular tissue. The dispersion profiles were subsequently fitted using a power law model. Statistical analysis focused on comparing potential FCI biomarkers using a Mann-Whitney U or Wilcoxon signed rank test.ResultsWe show that low magnetic fields clearly differentiate tumours from adipose and glandular tissues without contrast agents, particularly at 22 mT (1/T1, median [IQR]: 6.8 [3.9–7.8] s−1 vs 9.1 [8.9–10.2] s−1 vs 8.1 [6.2–9.2] s−1, P < 0.01), where the tumour-to-background contrast ratio was highest (62%). Additionally, 1/T1 dispersion indicated a potential to discriminate invasive from non-invasive cancers (median [IQR]: 0.05 [0.03–0.09] vs 0.19 [0.09–0.26], P = 0.038).ConclusionsTo the best of our knowledge, we described the first application of in vivo FCI in breast cancer, demonstrating relevant biomarkers that could complement diagnosis of current imaging modalities, non-invasively and without contrast agents.

MRI Super-Resolution Analysis via MRISR: Deep Learning for Low-Field Imaging

Abstract: This paper presents a novel MRI super-resolution analysis model, MRISR. Through the utilization of generative adversarial networks for the estimation of degradation kernels and the injection of noise, we have constructed a comprehensive dataset of high-quality paired high- and low-resolution MRI images. The MRISR model seamlessly integrates VMamba and Transformer technologies, demonstrating superior performance across various no-reference image quality assessment metrics compared with existing methodologies. It effectively reconstructs high-resolution MRI images while meticulously preserving intricate texture details, achieving a fourfold enhancement in resolution. This research endeavor represents a significant advancement in the field of MRI super-resolution analysis, contributing a cost-effective solution for rapid MRI technology that holds immense promise for widespread adoption in clinical diagnostic applications.

Thoracic MRI in pleural infection – a feasibility study from patients’ and radiographers’ perspectives

BackgroundPleural infections present significant clinical challenges, particularly in elderly or immunosuppressed patients, leading to prolonged hospital stay, high morbidity and high mortality. While CT and X-ray are standard imaging modalities, MRI's potential remain unexplored due to historical limitations in scan duration and patient discomfort. Advances in MRI technology, however, may enable its broader use in thoracic imaging. The study aimed to explore the feasibility of thoracic MRI from the radiographers’ and patients’ perspectives. MethodsA prospective feasibility study was conducted involving thirteen patients with pleural infections who underwent thoracic MRI as an add-on within 48 hours of the conventional contrast-enhanced chest CT. Feasibility was assessed on technical success, and scan duration. Patients and radiographers experiences were evaluated through questionnaires and qualitative comments. ResultsTechnical success was high as all thirteen patients completed the scans. The mean in-room time was 30.7±5.5 minutes and the mean scan time was 23±5.4 minutes. Radiographers reported the MRI scans as feasible with few patients requiring breaks or assistance. Most patients found the MRI experience manageable though two reported difficulties with breath-hold instructions. No patients were challenged by lying in supine position and no patients felt very anxious. No significant movement- or breathing artefacts were identified on MRI. ConclusionThoracic MRI is feasible with high technical success, acceptable scan time, and good patient experience in patients with pleural infections offering potential as a radiation-free imaging modality. Furthermore, compared to CT, the use of MRI showed potential advantages in identifying pleural effusion septations.

Advancements in the MRI technology for identification of dentomaxillofacial pathologies

Advancements in the MRI technology for identification of dentomaxillofacial pathologies

Myocardial Involvement in Catastrophic Antiphospholipid Syndrome during Pregnancy or Puerperium: A Case of a Young Breastfeeding Woman and Literature Review.

Catastrophic Antiphospholipid Syndrome (CAPS) is a rare complication that can occur in patients with Antiphospholipid Syndrome (APS). CAPS occurs even more rarely during pregnancy/puerperium and pregnant patients, even less likely to show cardiac involvement without signs of damage on ultrasound and angiography with non-obstructive coronary arteries. We present a case of a 26-year-old breastfeeding woman, the youngest described with CAPS and acute myocardial infarction, whose diagnosis was made with cardiac magnetic resonance imaging (CMRI). A literature review of pregnant patients with similar problems was performed. There are diagnostic and therapeutic difficulties in treating these patients. CMRI demonstrated a transmural late enhancement area. A combination of therapies led to rapid clinical improvement. CMRI is an underused tool that reaffirms the pathophysiology of CAPS and leads clinicians to the possibility of a diffuse thrombotic process. CAPS involves more organs with high mortality rates. CMRI could be optimized in order to reach an early diagnosis and the most effective treatment. This study provides real-world evidence of the feasibility of MRI in a primary care setting during pregnancy/puerperium. Evidence from this study may influence future APS screening and inform policymakers regarding the use of leading MRI technology in the detection of the thrombotic process in a primary care setting.

Model-predicted brain temperature computational imaging by multimodal noninvasive functional neuromonitoring of cerebral oxygen metabolism and hemodynamics: MRI-derived and clinical validation.

Brain temperature, a crucial yet under-researched neurophysiological parameter, is governed by the equilibrium between cerebral oxygen metabolism and hemodynamics. Therapeutic hypothermia has been demonstrated as an effective intervention for acute brain injuries, enhancing survival rates and prognosis. The success of this treatment hinges on the precise regulation of brain temperature. However, the absence of comprehensive brain temperature monitoring methods during therapy, combined with a limited understanding of human brain heat transmission mechanisms, significantly hampers the advancement of hypothermia-based neuroprotective therapies. Leveraging the principles of bioheat transfer and MRI technology, this study conducted quantitative analyses of brain heat transfer during mild hypothermia therapy. Utilizing MRI, we reconstructed brain structures, estimated cerebral blood flow and oxygen consumption parameters, and developed a brain temperature calculation model founded on bioheat transfer theory. Employing computational cerebral hemodynamic simulation analysis, we established an intracranial arterial fluid dynamics model to predict brain temperature variations across different therapeutic hypothermia modalities. We introduce a noninvasive, spatially resolved, and optimized mathematical bio-heat model that synergizes model-predicted and MRI-derived data for brain temperature prediction and imaging. Our findings reveal that the brain temperature images generated by our model reflect distinct spatial variations across individual participants, aligning with experimentally observed temperatures.

Nitroxide radical conjugated ovalbumin theranostic nanosystem for enhanced dendritic cell-based immunotherapy and T1 magnetic resonance imaging

Melanoma, known for its aggressive metastatic nature, presents a formidable challenge in cancer treatment, where conventional therapies often fall short. This study introduces a pioneering approach utilizing metal-free nanosystem as tumor vaccines, spotlighting their potential in revolutionizing melanoma treatment. This work employed organic nitroxides, specifically 4-carboxy-TEMPO, in combination with chitosan (CS), to create a novel nanocomposite material - the CS-TEMPO-OVA nanovaccines. This composition not only improves biocompatibility and extends blood circulation time of TEMPO but also marks a significant departure from traditional gadolinium-based contrast agents in MRI technology, addressing safety concerns. CS-TEMPO-OVA nanovaccines demonstrate excellent biocompatibility at both the cellular and organoid level. They effectively stimulate bone marrow-derived dendritic cells (BMDCs), which in turn promote the maturation and activation of T cells. This ultimately leads to a strong production of essential cytokines. These nanovaccines serve a dual purpose as both therapeutic and preventive. By inducing an immune response, activating cytotoxic T cells, and promoting macrophage M1 polarization, they effectively inhibit melanoma growth and enhance survival in mouse models. When combined with αPD-1, the CS-TEMPO-OVA nanovaccines significantly bolster the infiltration of cytotoxic T lymphocytes (CTLs) within tumors, sparking a powerful systemic antitumor response that effectively curbs tumor metastasis. The ability of these nanovaccines to control both primary (subcutaneous) and metastatic B16-OVA tumors highlights their remarkable efficacy. Furthermore, the CS-TEMPO-OVA nanovaccine can be administered in vivo via both intravenous and intramuscular routes, both of which effectively enhance the T1 contrast of magnetic resonance imaging in tumor tissue. This study offers invaluable insights into the integrated application of these nanovaccines in both clinical diagnostics and treatment, marking a significant stride in cancer research and patient care.

Assessment of the Diagnostic Efficacy of Low-Field Magnetic Resonance Imaging: A Systematic Review.

In recent years, there has been an increasing effort to take advantage of the potential use of low magnetic induction devices with less than 1 T, referred to as Low-Field MRI (LF MRI). LF MRI systems were used, especially in the early days of magnetic resonance technology. Over time, magnetic induction values of 1.5 and 3 T have become the standard for clinical devices, mainly because LF MRI systems were suffering from significantly lower quality of the images, e.g., signal-noise ratio. In recent years, due to advances in image processing with artificial intelligence, there has been an increasing effort to take advantage of the potential use of LF MRI with induction of less than 1 T. This overview article focuses on the analysis of the evidence concerning the diagnostic efficacy of modern LF MRI systems and the clinical comparison of LF MRI with 1.5 T systems in imaging the nervous system, musculoskeletal system, and organs of the chest, abdomen, and pelvis. A systematic literature review of MEDLINE, PubMed, Scopus, Web of Science, and CENTRAL databases for the period 2018-2023 was performed according to the recommended PRISMA protocol. Data were analysed to identify studies comparing the accuracy, reliability and diagnostic performance of LF MRI technology compared to available 1.5 T MRI. A total of 1275 publications were retrieved from the selected databases. Only two articles meeting all predefined inclusion criteria were selected for detailed assessment. A limited number of robust studies on the accuracy and diagnostic performance of LF MRI compared with 1.5 T MRI was available. The current evidence is not sufficient to draw any definitive insights. More scientific research is needed to make informed conclusions regarding the effectiveness of LF MRI technology.

Aortic Regurgitation in Bicuspid Aortic Valve: The Role of Multimodality Imaging.

The evaluation of aortic regurgitation (AR) in bicuspid valve (BAV) is still a challenge because of the eccentricity of the jet, which may under/overestimate the regurgitation. The commonly used echocardiography parameters (such as vena contracta, pressure half-time, etc.) may not be useful in this kind of patient. A multimodality approach combining echocardiography, cardiac MRI, cardiac CT, and advanced technologies applied to non-invasive cardiac imaging (e.g., 4D flow and strain imaging) may be useful to better quantify regurgitation and to select patients suitable for valve replacement. This review provides an overview of the most recent insights about cardiovascular imaging tools and their utility in BAV evaluation, focusing on chronic regurgitation. We describe the role of multimodality imaging in both diagnosis and risk assessment of this disease, pointing out the advantages and disadvantages of the imaging techniques, aiming to provide a guide to clinicians and cardiovascular imaging specialists in choosing the best imaging tools to use.

Comparative Analysis of MRI Image Reconstruction Techniques for Improved Diagnosis

This paper presents a comparative analysis of MRI image reconstruction techniques aimed at enhancing diagnostic accuracy. The study investigates various reconstruction methods to improve image quality and aid in precise medical diagnosis. Through a systematic evaluation, the effectiveness of each technique is assessed, considering factors such as computational efficiency, artifact reduction, and diagnostic utility. The results highlight the strengths and limitations of different approaches, providing valuable insights for medical imaging practitioners and researchers. Ultimately, this research contributes to advancing MRI technology and facilitating more accurate and efficient diagnosis.

Advances in functional and structural imaging of the brainstem: implications for disease.

The brainstem's complex anatomy and relatively small size means that structural and functional assessment of this structure is done less frequently compared to other brain areas. However, recent years have seen substantial progress in brainstem imaging, enabling more detailed investigations into its structure and function, as well as its role in neuropathology. Advancements in ultrahigh field MRI technology have allowed for unprecedented spatial resolution in brainstem imaging, facilitating the new creation of detailed brainstem-specific atlases. Methodological improvements have significantly enhanced the accuracy of physiological (cardiac and respiratory) noise correction within brainstem imaging studies. These technological and methodological advancements have allowed for in-depth analyses of the brainstem's anatomy, including quantitative assessments and examinations of structural connectivity within both gray and white matter. Furthermore, functional studies, including assessments of activation patterns and functional connectivity, have revealed the brainstem's roles in both specialized functions and broader neural integration. Notably, these investigations have identified alterations in brainstem structure and function associated with various neurological disorders. The aforementioned developments have allowed for a greater appreciation of the importance of the brainstem in the wider context of neuroscience and clinical neurology.

High-Resolution Magnetic Resonance Neurography at 7T: A Pilot Study of Hand Innervation.

The emergence of 7T clinical MRI technology has sparked our interest in its ability to discern the complex structures of the hand. Our primary objective was to assess the sensory and motor nerve structures of the hand, specifically nerves and Pacinian corpuscles, with the dual purpose of aiding diagnostic endeavors and supporting reconstructive surgical procedures. Ethical approval was obtained to carry out 7T MRI scans on a cohort of volunteers. Four volunteers assumed a prone position, with their hands (N = 8) positioned in a "superman" posture. To immobilize and maintain the hand in a strictly horizontal position, it was affixed to a plastic plate. Passive B0 shimming was implemented. Once high-resolution 3D images had been acquired using a multi-transmit head coil, advanced post-processing techniques were used to meticulously delineate the nerve fiber networks and mechanoreceptors. Across all participants, digital nerves were consistently located on the phalanges area, on average, between 2.5 and 3.5 mm beneath the skin, except within flexion folds where the nerve was approximately 1.8 mm from the surface. On the phalanges area, the mean distance from digital nerves to joints was approximately 1.5 mm. The nerves of the fingers were closer to the bone than to the surface of the skin. Furthermore, Pacinian corpuscles exhibited a notable clustering primarily within the metacarpal zone, situated on the palmar aspect. Our study yielded promising results, successfully reconstructing and meticulously describing the anatomy of nerve fibers spanning from the carpus to the digital nerve division, alongside the identification of Pacinian corpuscles, in four healthy volunteers (eight hands).

Estrogen deficiency induces changes in bone matrix bound water that do not closely correspond with bone turnover

Postmenopausal osteoporosis, marked by estrogen deficiency, is a major contributor to osteoporotic fractures, yet early prediction of fractures in this population remains challenging. Our goal was to explore the temporal changes in bone-specific inflammation, oxidative stress, bone turnover, and bone-matrix water, and their relationship with estrogen deficiency-induced modifications in bone structure and mechanical properties. Additionally, we sought to determine if emerging clinically translatable imaging techniques could capture early bone modifications prior to standard clinical imaging.Two-month-old female Sprague Dawley rats (n = 48) underwent ovariectomy (OVX, n = 24) or sham operations (n = 24). A subgroup of n = 8 rats per group was sacrificed at 2-, 5-, and 10-weeks post-surgery to assess the temporal relationships of inflammation, oxidative stress, bone turnover, bone matrix water, mechanics, and imaging outcomes.OVX rats exhibited higher body weight compared to sham rats at all time points. By 5-weeks, OVX animals showed elevated markers of inflammation and oxidative stress in cortical bone, which persisted throughout the study, while cortical bone formation rate did not differ from sham until 10-weeks. DXA outcomes did not reveal differences between OVX and sham at any time point. Bound water, assessed using ultrashort echo time magnetic resonance imaging (UTE MRI), was lower in OVX at the earliest time point (2-weeks) and reduced again at 10-weeks with no difference at 5-weeks.These data demonstrate that bound water assessment using novel UTE MRI technology was lower at the earliest time point following OVX. However, no temporal relationship with bone turnover, inflammation, or oxidative stress was observed at the time points assessed in this study. These findings underscore both the increased need to understand bone hydration changes and highlight the usefulness of UTE MRI for non-invasive bone hydration measurements.

Myocardial and Skeletal Muscle Microvascular Dysfunction Manifests Prior to Diabetic Cardiomyopathy: Sex-Dependent Differences

Introduction: Microvascular dysfunction is a recognized sign of disease in heart failure progression. Blood vessels exhibit abnormal vasoreactivity in early stage, subsequently deteriorating to rarefaction and reduced perfusion. In managing heart failure patients, where diagnosis is typically possible only when the hypertrophic heart is irreversibly damaged, earlier diagnosis is key to improving management. In this study, we apply a blood-pool MRI method for assessing vasomodulation to investigate if it can sensitively detect abnormal leg muscle vasoreactivity posited to manifest before myocardial mvD. Methods: Male and female Sprague-Dawley rats were maintained on a high-fat, high-sugar diet or a control diet for 6 months after the induction of diabetes. Beginning at month 1 or 2 post-induction and every 2 months thereafter, rats underwent blood-pool MRI to assess vasoreactivity in the heart or skeletal muscle, respectively. Ablavar, a T1-reducing blood-pool contrast agent, was administered and the T1 relaxation time dynamically measured as animals breathed in mild CO2 levels to modulate vessels and elicit a vasodilatory response. CO2 levels were set at 5% for skeletal muscle and 10% for cardiac muscle, and the gas was administered for 10 minutes. At the final timepoint, invasive laser Doppler perfusion measurements in leg muscle were recorded to verify MRI results. Results/Discussion: In this study, we provide the first demonstration that both skeletal muscle and myocardial microvascular vasoreactivity is altered in a non-obese rodent model of type II diabetes, prior to the development of heart failure symptoms. In male rats, the normally unresponsive heart to 10% CO2 reveals a pro-vasoconstriction response beginning at 5 months post-diabetes. Abnormal leg skeletal muscle vasoreactivity appeared even earlier, at 2 months: the usual vasodilatory response to 5% CO2 is interrupted with periods of vasoconstriction in diseased rats. In female rats, differences were observed between healthy and diseased animals only within the first two months post-diabetes and not later. In the heart, vasodilation to 10% CO2 seen in healthy animals was abolished in diabetes. In skeletal muscle, 5% CO2 was suboptimal in inducing reproducible vasoreactivity, but young diabetic females responded by vasodilation only. Conclusion: Abnormal vasoreactivity presents earlier than overt structural and functional cardiac changes in both sexes in HFpEF and can be detected using blood-pool MRI in leg skeletal muscle before the myocardium. Our non-invasive MRI technology sets the foundation for a paradigm shift in diagnosing mvD during the early stages of HFpEF, opening the door for early intervention. This work was supported by the Canadian Institutes of Health Research, Natural Sciences and Engineering Research Council of Canada, Canada Foundation for Innovation/Ontario Research Fund, Dean’s Spark Professorship, Medicine by Design Pivotal Experiment Fund [to H.L.M.C.]; Ted Rogers Centre for Heart Research PhD Education Fund, Scintica Instrumentation Inc [to S.L.]. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Visualizing and Regulating Dynamic Evolution of Interfacial Electrolyte Configuration during De‐solvation Process on Lithium‐Metal Anode

AbstractActing as a passive protective layer, solid‐electrolyte interphase (SEI) plays a crucial role in maintaining the stability of the Li‐metal anode. Derived from the reductive decomposition of electrolytes (e.g., anion and solvent), the SEI construction presents as an interfacial process accompanied by the dynamic de‐solvation process during Li‐metal plating. However, typical electrolyte engineering and related SEI modification strategies always ignore the dynamic evolution of electrolyte configuration at the Li/electrolyte interface, which essentially determines the SEI architecture. Herein, by employing advanced electrochemical in situ FT‐IR and MRI technologies, we directly visualize the dynamic variations of solvation environments involving Li+‐solvent/anion. Remarkably, a weakened Li+‐solvent interaction and anion‐lean interfacial electrolyte configuration have been synchronously revealed, which is difficult for the fabrication of anion‐derived SEI layer. Moreover, as a simple electrochemical regulation strategy, pulse protocol was introduced to effectively restore the interfacial anion concentration, resulting in an enhanced LiF‐rich SEI layer and improved Li‐metal plating/stripping reversibility.

Visualizing and Regulating Dynamic Evolution of Interfacial Electrolyte Configuration during De-solvation Process on Lithium-Metal Anode.

Acting as a passive protective layer, solid-electrolyte interphase (SEI) plays a crucial role in maintaining the stability of the Li-metal anode. Derived from the reductive decomposition of electrolytes (e.g., anion and solvent), the SEI construction presents as an interfacial process accompanied by the dynamic de-solvation process during Li-metal plating. However, typical electrolyte engineering and related SEI modification strategies always ignore the dynamic evolution of electrolyte configuration at the Li/electrolyte interface, which essentially determines the SEI architecture. Herein, by employing advanced electrochemical in situ FT-IR and MRI technologies, we directly visualize the dynamic variations of solvation environments involving Li+-solvent/anion. Remarkably, a weakened Li+-solvent interaction and anion-lean interfacial electrolyte configuration have been synchronously revealed, which is difficult for the fabrication of anion-derived SEI layer. Moreover, as a simple electrochemical regulation strategy, pulse protocol was introduced to effectively restore the interfacial anion concentration, resulting in an enhanced LiF-rich SEI layer and improved Li-metal plating/stripping reversibility.

Altered neural representation of olfactory food reward in the nucleus accumbens after acute stress

Acute stress impairs reward processing. The nucleus accumbens (NAcc) plays an important role in the processing of primary rewards such as food. The present study investigates how acute stress affects the olfactory food reward processing in the NAcc using the representational similarity analysis. Forty-eight participants underwent an olfactory fMRI session following either an acute psychosocial stress (N = 24; stress group) or a control (N = 24; control group). Brain activation was recorded during the anticipatory and the perceptual phases of high-calorie food, low-calorie food, and non-food odor stimuli. Compared to the control group, the stress group rated the high-calorie food odor as significantly more pleasant (p = 0.005). In the NAcc, acute stress significantly reduced the dissimilarity of food and non-food odors in the perceptual phase (p = 0.027) and marginally reduced the dissimilarity of high- and low-calorie foods in the anticipatory phase (p = 0.095). Significant negative correlations were observed between the level of NAcc representational differentiation for high- and low-calorie food odors during perception and the difference in pleasantness ratings between high- and low-calorie food odors (r = -0.40, p = 0.005). These findings suggest that acute stress may impair participants’ ability to discriminate between olfactory food rewards, leading individuals to seek out more palatable foods in stressful situations in order to maintain positive emotions.