Magnetic Resonance Imaging Studies Research Articles

Deciphering white matter microstructural alterations in catatonia according to ICD-11: replication and machine learning analysis

AbstractCatatonia is a severe psychomotor disorder characterized by motor, affective and cognitive-behavioral abnormalities. Although previous magnetic resonance imaging (MRI) studies suggested white matter (WM) dysconnectivity in the pathogenesis of catatonia, it is unclear whether microstructural alterations of WM tracts connecting psychomotor regions might contribute to a better classification of catatonia patients. Here, diffusion-weighted MRI data were collected from two independent cohorts (whiteCAT/replication cohort) of patients with (n = 45/n = 13) and without (n = 56/n = 26) catatonia according to ICD-11 criteria. Catatonia severity was examined using the Northoff (NCRS) and Bush-Francis (BFCRS) Catatonia Rating Scales. We used tract-based spatial statistics (TBSS), tractometry (TractSeg) and machine-learning (ML) to classify catatonia patients from tractometry values as well as tractomics features generated by the newly developed tool RadTract. Catatonia patients showed fractional anisotropy (FA) alterations measured via TractSeg in different corpus callosum segments (CC_1, CC_3, CC_4, CC_5 and CC_6) compared to non-catatonia patients across both cohorts. Our classification results indicated a higher level of performance when trained on tractomics as opposed to traditional tractometry values. Moreover, in the CC_6, we successfully trained two classifiers using the tractomics features identified in the whiteCAT data. These classifiers were applied separately to the whiteCAT and replication cohorts, demonstrating comparable performance with Area Under the Receiver Operating Characteristics (AUROC) values of 0.79 for the whiteCAT cohort and 0.76 for the replication cohort. In contrast, training on FA tractometry resulted in lower AUROC values of 0.66 for the whiteCAT cohort and 0.51 for the replication cohort. In conclusion, these findings underscore the significance of CC WM microstructural alterations in the pathophysiology of catatonia. The successful use of an ML based classification model to identify catatonia patients has the potential to improve diagnostic precision.

The Development of Socially Directed Attention: A Functional Magnetic Resonance Imaging Study in Infant Monkeys.

Socially guided visual attention, such as gaze following and joint attention, represents the building block of higher-level social cognition in primates, although their neurodevelopmental processes are still poorly understood. Atypical development of these social skills has served as early marker of autism spectrum disorder and Williams syndrome. In this study, we trace the developmental trajectories of four neural networks underlying visual and attentional social engagement in the translational rhesus monkey model. Resting-state fMRI (rs-fMRI) data and gaze following skills were collected in infant rhesus macaques from birth through 6 months of age. Developmental trajectories from subjects with both resting-state fMRI and eye-tracking data were used to explore brain-behavior relationships. Our findings indicate robust increases in functional connectivity (FC) between primary visual areas (primary visual cortex [V1] - extrastriate area 3 [V3] and V3 - middle temporal area [MT], MT and anterior superior temporal sulcus area [AST], as well as between anterior temporal area [TE]) and amygdala (AMY) as infants mature. Significant FC decreases were found in more rostral areas of the pathways, such as between temporal area occipital part - TE in the ventral object pathway, V3 - lateral intraparietal (LIP) of the dorsal visual attention pathway and V3 - temporo-parietal area of the ventral attention pathway. No changes in FC were found between cortical areas LIP-FEF and temporo-parietal area - Area 12 of the dorsal and ventral attention pathways or between Anterior Superior Temporal sulcus area (AST)-AMY and AMY-insula. Developmental trajectory of gaze following revealed a period of dynamic changes with gradual increases from 1 to 2 months, followed by slight decreases from 3 to 6 months. Exploratory association findings across the 6-month period showed that infants with higher gaze following had lower FC between primary visual areas V1-V3, but higher FC in the dorsal attention areas V3-LIP, both in the right hemisphere. Together, the first 6 months of life in rhesus macaques represent a critical period for the emergence of gaze following skills associated with maturational changes in FC of socially guided attention pathways.

White matter correlates of impulsive behavior in healthy individuals: A diffusion magnetic resonance imaging study.

To explore white matter (WM) tracts linked to impulsivity using the diffusion magnetic resonance imaging (DMRI) connectometry method. We analyzed 218 healthy participants from the Leipzig Study for Mind-Body-Emotion Interactions database. Impulsivity correlations with DMRI-derived WM changes were assessed using Urgency-Premeditation-Perseverance-Sensation (UPPS) Impulsive Behavior Scale subscales: lack of perseverance (PE), lack of premeditation (PM), sensation seeking (SS), and negative urgency. DMRI data were processed using connectometry, adjusting for sex and age, to examine WM tract integrity via quantitative anisotropy (QA). Also, two additional interaction analyses were conducted to separately examine the interaction effect between WM QA, and sex and age in predicting impulsive behavior scores. The significance level in our statistical analyses was set at a false discovery rate (FDR) below 0.05. QA in the bilateral cerebellum and middle cerebellar peduncle showed a negative association with PE and PM severity (FDR = 0.0004). QA in the middle cerebellar peduncle, corpus callosum body, and forceps major demonstrated a positive association with SS (FDR = 0.0001). Conversely, QA in forceps minor had a positive association with PM (FDR = 0.004), and QA in forceps minor and bilateral cingulum showed a positive association with SS (FDR = 0.0005). Age and sex had no significant effects on the association between WM QA and UPPS subscale scores. Impulsivity is linked to distinct WM integrity changes in various tracts, including the corpus callosum, cerebellum, and cingulum, offering insights into the pathophysiology of impulsivity and guiding future research.

Exposure duration and cerebral amyloidosis in the olfactory cortex of World Trade Center responders: A positron emission tomography and magnetic resonance imaging study.

Amyloid-β proteins, a hallmark of Alzheimer's disease, are believed to play an adaptive role in the cerebral immune response. Amyloid is believed to play a role in cerebral immune response and could play a similar role in response to air pollution exposures. In the present study, we examined whether WTC exposure duration was associated with cerebral amyloidosis in WTC responders. WTC responders (aged 44-65 years) who varied in exposure duration but did not use personalized protective equipment were assessed using positron-emission tomography with [18F]-Florbetaben. The outcome was the cortical [18F]-Florbetaben burden, measured using regional standardized uptake value ratios (SUVRs) in 34 Desikan-Killiany regions of interest. Spearman's ρ and generalized linear models were used to estimate correlations between WTC exposure duration and cortical [18F]-Florbetaben SUVR. Cognitive and behavioral symptoms were measured. Magnetic resonance imaging was used to measure cortical thickness and diffusivity. The mean age of imaged responders was 56 years old. WTC exposure duration was associated with olfactory [18F]-Florbetaben SUVR (Spearman's ρ = 0.43, p = 0.011), which was in turn associated with elevated [18F]-Florbetaben SUVR in ventral regions (ρ = 0.41, p = 0.016). Cortical [18F]-Florbetaben in ventral regions was associated with reduced response speed (ρ = -0.72, p < 0.001), was co-located with cortical diffusivity across regions in the parietal and frontal lobes and reduced cortical thickness in the isthmus cingulate (ρ = -0.53, p = 0.001). Low-grade amyloidosis in the olfactory and frontal lobes was associated with WTC exposure duration. Future work should examine whether low-grade amyloidosis is correlated with the location or distribution of neurofibrillary tangles in WTC responders.

Exploring the effects of erythropoietin treatment on cortical thickness and hippocampal volume in patients with mood disorders undergoing electroconvulsive therapy: A randomized, placebo-controlled trial.

Electroconvulsive therapy (ECT) is a highly effective treatment for severe depression. However, its utilization is limited to the most severely ill patients due to stigma, healthcare provider unfamiliarity, and concerns regarding cognitive side effects. Erythropoietin (EPO) is a promising add-on treatment during ECT due to its potential to increase neuroplasticity and cognition. To explore the effects of EPO administration on cortical thickness and hippocampal volumes. In a randomized, double-blinded, placebo-controlled trial, we previously investigated the impact of EPO (40,000 IU) versus placebo (saline) infusions on cognitive side effects of unipolar or bipolar depression patients undergoing eight ECT sessions over 2.5 weeks. This cross-sectional magnetic resonance imaging study explores the effect of EPO on cortical thickness and hippocampal volumes 3 days post-ECT in 37 of the EPO trial patients (EPO n = 21; placebo n = 16). Compared to the placebo group, EPO-treated patients displayed thicker cortex in distributed regions of the right hemisphere, predominantly in the parietal and occipital areas. There were no significant group differences in the hippocampal volumes or prefrontal cortex thickness. EPO treatment may produce a selective increase in the right-side occipito-parietal cortical thickness. In contrast, the thickness of other cognition-relevant structures was not significantly affected. This aligns with our previously reported finding that EPO has a selective effect on autobiographical memory and associated right-side parietal activity in the absence of changes in global cognition. It remains to be investigated whether longer EPO treatment and follow-up assessment may be necessary for overt structural changes in cognition-relevant brain networks.

Contribution of Magnetic Resonance Imaging Studies to the Understanding of Cerebral Malaria Pathogenesis

Cerebral malaria (CM), the most lethal clinical syndrome of Plasmodium falciparum infection, mostly affects children under 5 in sub-Saharan Africa. CM is characterized by seizures and impaired consciousness that lead to death in 15–20% of cases if treated quickly, but it is completely fatal when untreated. Brain magnetic resonance imaging (MRI) is an invaluable source of information on the pathophysiology of brain damage, but, due to limited access to scanners in endemic regions, only until very recently have case reports of CM patients studied with advanced MRI methods been published. The murine model of experimental cerebral malaria (ECM) shares many common features with the human disease and has been extensively used to study the pathogenic mechanisms of the neurological syndrome. In vivo MRI studies on this model, the first of which was published in 2005, have contributed to a better understanding of brain lesion formation in CM and identified disease markers that were confirmed by MRI studies published from 2013 onwards in pediatric patients from endemic areas. In this review, we recapitulate the main findings and critically discuss the contributions of MRI studies in the ECM model to the understanding of human CM.

A comparative meta-analysis of structural magnetic resonance imaging studies and gene expression profiles revealing the similarities and differences between late life depression and mild cognitive impairment.

Late-life depression (LLD) predisposes individuals to cognitive decline, often leading to misdiagnoses as mild cognitive impairment (MCI). Voxel-based morphometry (VBM) can distinguish the profiles of these disorders according to gray matter (GM) volumes. We integrated findings from previous VBM studies for comparative analysis and extended the research into molecular profiles to facilitate inspection and intervention. We comprehensively searched PubMed and Web of Science for VBM studies that compared LLD and MCI cases with matched healthy controls (HCs) from inception to 31st December 2023. We included 13 studies on LLD (414 LLDs, 350 HCs) and 50 on MCI (1878 MCIs, 2046 HCs). Seed-based d Mapping with Permutation of Subject Images (SDM-PSI) was used for voxel-based meta-analysis to assess GM atrophy, spatially correlated with neuropsychological profiles. We then used multimodal and linear-model analysis to assess the similarities and differences in GM volumetric changing patterns. Partial least squares (PLS) regression and gene enrichment were employed for transcription-neuroimaging associations. GM volumes in the left hippocampus and right parahippocampal gyrus are more affected in MCI, along with memory impairment. MCI was spatially correlated with a more extensive reduction in the levels of neurotransmitters and a severe downregulation of genes related to cellular potassium ion transport and metal ion transmembrane transporter activity. Compared to LLD, MCI exhibited more GM atrophy in the hippocampus and parahippocampal gyrus and lower gene expression of ion transmembrane transport. Our findings provided imaging-transcriptomic-genetic integrative profiles for differential diagnosis and precise intervention between LLD and MCI.

Tuned Manganese-Impregnated Mesoporous Silica Nanoparticles as a pH-Responsive Dual Imaging Probe.

The limitations of individual imaging modalities have led to significant interest in hybrid imaging methods that combine the advantages of multiple techniques. The development of diverse dual imaging agents, which offer the exceptional sensitivity of single-photon emission computed tomography (SPECT) and the high spatial resolution of magnetic resonance imaging (MRI), has been addressing the demand for more advanced diagnostic pharmaceuticals. In this study, 99mTc-labeled manganese oxide-loaded mesoporous silica nanoparticles (MSNs), conjugated with folic acid as the targeting moiety and the chelating agent H2pentapa-en-NH2 (99mTc-MnOx-MSN-FA-pa), were developed for targeted SPECT-MRI dual imaging. The toxicity of the nanoparticles was confirmed through an MTT assay, showing >90% viability in HEK-293 and MDA-MB-231 cells at concentrations up to 200 μg/mL, indicating nonsignificant toxicity. Cellular uptake studies showed that folic acid functionalization effectively accentuated tumor-specific intracellular uptake of nanoparticles in MDA-MB-231 cells through folate receptor-mediated endocytosis. Additionally, the radiolabeling yield of 99mTc-MnOx-MSN-FA-pa was found to be 99.6 ± 0.8% (n = 3), and the pH-responsive release of paramagnetic manganese ions increased the r1 relaxivity of the nanoprobe to 11.37 mM-1 s-1. In vivo SPECT imaging demonstrated rapid tracer accumulation in MDA-MB-231 xenografts, with a tumor-to-muscle ratio of 6.01 ± 0.51 at 2 h, and minimal uptake in nontargeted organs. In vivo MRI studies indicated the strongest tumor contrast at 2 h postinjection. Given its desirable contrast enhancement in T1 MRI and SPECT imaging, along with low toxicity, MnOx-MSN-FA-pa shows potential as an effective multifunctional nanoprobe for precise tumor imaging.

White matter lesions contribute to motor and non-motor disorders in Parkinson's disease: a critical review.

Parkinson's disease (PD) is a prevalent neurodegenerative disease, characterized by movement disorders and non-motor symptoms like cognitive impairment and depression. Degeneration of dopaminergic neurons in the substantia nigra and Lewy bodies have long been considered as main neuropathological changes. However, recent magnetic resonance imaging (MRI) studies have shown that white matter lesions (WMLs) were present in PD patients. WMLs are characterized by loss or impairment of myelin sheath in central nerve fibers, which are closely correlated with motor and cognitive dysfunction in PD. WMLs alterations precede nigrostriatal neuronal losses and can independently affect the clinical severity or characteristics of motor coordination in PD patients. Currently, the exact mechanism of WMLs involvement in the occurrence and development of PD remains unclear. It is speculated that WMLs may participate in the pathogenesis of PD by disrupting important connections in brain or promoting axonal degeneration. In this review, we will discuss the pathological changes and mechanisms of WMLs, elaborate the impact of WMLs on the progression of PD, clarify the importance of WMLs in PD pathogenesis, and thus provide novel targets for PD treatments.

Individual differences in functional connectivity during suppression of imagined threat.

Functional magnetic resonance imaging studies typically rely on between-person analyses. To examine individual differences in functional connectivity, we used Group Iterative Multiple Model Estimation and its subgrouping function to analyze functional magnetic resonance imaging data of 54 participants who were suppressing imagined future threat. A two-stage random-effects meta-analytic approach was employed to examine individual differences. In addition to generalizable connections between brain regions, we identified individual differences in personalized models suggesting different pathways through which individuals suppress future threat. Two subgroups with distinct connectivity patterns emerged: One subgroup (n = 29; 53.70%), characterized by an additional lagged connection from the right to the left posterior cingulate cortex, exhibited comparatively higher anxiety and less brain connectivity, whereas the other subgroup (n = 25; 46.30%), showing an additional connection from the left posterior cingulate cortex to the ventromedial prefrontal cortex, was associated with lower anxiety levels and greater connectivity. This study points to individual differences in functional connectivity during emotion regulation.

Resolution-dependent MRI-to-CT translation for orthotopic breast cancer models using deep learning

Objective.This study aims to investigate the feasibility of utilizing generative adversarial networks (GANs) to synthesize high-fidelity computed tomography (CT) images from lower-resolution MR images. The goal is to reduce patient exposure to ionizing radiation while maintaining treatment accuracy and accelerating MR image acquisition. The primary focus is to determine the extent to which low-resolution MR images can be utilized to generate high-quality CT images through a systematic study of spatial resolution-dependent magnetic resonance imaging (MRI)-to-CT image conversion.Approach.Paired MRI-CT images were acquired from healthy control and tumor models, generated by injecting MDA-MB-231 and 4T1 tumor cells into the mammary fat pad of nude and BALB/c mice to ensure model diversification. To explore various MRI resolutions, we downscaled the highest-resolution MR image into three lower resolutions. Using a customized U-Net model, we automated region of interest masking for both MRI and CT modalities with precise alignment, achieved through three-dimensional affine paired MRI-CT registrations. Then our customized models, Nested U-Net GAN and Attention U-Net GAN, were employed to translate low-resolution MR images into high-resolution CT images, followed by evaluation with separate testing datasets.Main Results.Our approach successfully generated high-quality CT images (0.142mm2) from both lower-resolution (0.282mm2) and higher-resolution (0.142mm2) MR images, with no statistically significant differences between them, effectively doubling the speed of MR image acquisition. Our customized GANs successfully preserved anatomical details, addressing the typical loss issue seen in other MRI-CT translation techniques across all resolutions of MR image inputs.Significance.This study demonstrates the potential of using low-resolution MR images to generate high-quality CT images, thereby reducing radiation exposure and expediting MRI acquisition while maintaining accuracy for radiotherapy.

Aberrant intrinsic brain activities in functional gastrointestinal disorders revealed by seed-based d mapping with permutation of subject images.

Functional gastrointestinal disorders (FGIDs) are characterized by complex interactions between the gut and brain, leading to altered brain function and symptom manifestation. We used neuroimaging meta-analytic techniques in order to analyze the correlation between FGIDs and aberrant brain activity. A systematic review was performed to ascertain resting-state functional magnetic resonance imaging (rs-fMRI) studies examining brain function in FGIDs. Pooled meta-analyses by seed-based d mapping with permutation of subject images (SDM-PSI) were performed to assess variations in regional brain activity, and sensitivity analyses were applied to evaluate the robustness of findings. Meta-regression analyses were then carried out to examine possible links between demographic factors and neuroimaging changes. Our meta-analysis revealed significant changes in regional brain activities among FGIDs patients compared to healthy controls (HC). Increased brain activation was observed in several regions including the postcentral gyrus, calcarine fissure/surrounding cortex, superior frontal gyrus, and insula, while decreased activity was noted in the left posterior cingulate gyrus, right median cingulate/paracingulate gyri, and the left caudate nucleus. Furthermore, meta-regression analyses indicated negative associations between disease duration and alterations in specific brain regions. These findings underscored the intricate interplay between gut dysfunction and aberrant brain activity in FGIDs. Early intervention and multidisciplinary approaches addressing both gastrointestinal symptoms and associated emotional distress are crucial for improving the quality of life of the patients.

Altered parasympathetic outflow and central sensitization response to continuous pain in cyclic vomiting syndrome: a functional magnetic resonance imaging study.

Cyclic vomiting syndrome (CVS) is a disorder of brain-gut interaction characterized by recurrent episodes of nausea and vomiting interspersed with asymptomatic periods and associated with autonomic nervous system dysfunction. We examined the dysautonomic response to noxious stimuli seen in CVS patients using our previously validated approach to integrate peripheral autonomic outflow metrics, temporal summation of pain, and brain fMRI. BOLD fMRI and ECG were acquired from CVS patients and healthy adults during a rest condition and a sustained cuff pressure pain stimulus at the leg. After the latter scan, participants rated pain for the full 6-minute pain stimulus as well as first, middle, and last two-minutes to calculate temporal summation. During sustained pain, patients (n=13) exhibited greater reduction in heart rate variability within the high-frequency range (HF-HRV) and reduced anticorrelation between HF-HRV and fMRI signal in the anterior insula, pregenual anterior cingulate cortex, and ventrolateral and dorsolateral prefrontal cortex relative to healthy adults (n=13). Compared to healthy adults (n=14), patients (n=14) exhibited increasing pain intensity over the course of sustained cuff pressure. Seed-based functional connectivity analysis revealed for healthy adults (n=13), pain sensitization correlated with pain-induced increases in connectivity between primary somatosensory cortex and regions of interest in both left anterior insula/posterior orbitofrontal cortex and right pre-supplementary motor area, while this correlation was disrupted in CVS (n=10). Our results support altered central coding of nociceptive stimuli and autonomic responsivity of CVS patients in key brain regions implicated in autonomic control and interoception.

Assessment of All-Inside Sutures to the Posteromedial Capsule in Medial Meniscus Posterior Root Repair: Findings From a Retrospective Three-Dimensional Magnetic Resonance Imaging Study

Assessment of All-Inside Sutures to the Posteromedial Capsule in Medial Meniscus Posterior Root Repair: Findings From a Retrospective Three-Dimensional Magnetic Resonance Imaging Study

Case Report: Periocular Steroid Injection Combined Vemurafenib Therapy in the Long-term Management of Orbital Involvement of Erdheim-Chester Disease.

Abstract Purpose: To report a rare case of vision loss from Erdheim-Chester Disease (ECD) and long term, follow up, management and results. Case Report: A 62-year-old woman presented with bilateral exophthalmos and deterioration in visual acuity of both eyes. Magnetic resonance imaging studies revealed bilateral intraconal orbital tumors. She was diagnosed optic neuropathy in both eyes. The patient was treated with pegylated interferon and systemic pulse steroid. However, recurrences were common. Subsequently, the patient underwent regular corticosteroid injection directly into the retro-orbital region of both eyes monthly, which led to intermittent improvement of vision. At the 8th month of visual impairment, Vemurafenib was initiated. Results: The visual acuity and visual field scores were stable for 6 years during the follow-up. No major complication was observed. Conclusion: Combined vemurafenib and perioculer steroid injection is a well tolerated therapy with less systemic adverse effects which may benefit patients with orbital involvement of ECD. Key words: Erdheim–Chester disease; compressive optic neuropathy; vemurafenib; Optical coherence tomography; Optical coherence tomography angiography.

The Added Value of Apparent Diffusion Coefficient and Histogram Analysis in Assessing Treatment Response of Locally Advanced Cervical Cancer

Objective The aim of the study is to assess the diagnostic performance of quantitative analysis of diffusion-weighted imaging in assessing treatment response in cervical cancer patients. Methods A retrospective analysis was done for 50 patients with locally advanced cervical cancer who received concurrent chemoradiotherapy and underwent magnetic resonance imaging and diffusion-weighted imaging. Treatment response was classified into 4 categories according to RECIST criteria 6 months after therapy completion. Apparent diffusion coefficient (ADC) values were measured using both region of interest (ROI) ADC and whole lesion (WL) ADC histogram for all cases at both baseline pretreatment and posttreatment Magnetic resonance imaging studies. Changes in ADC values were calculated and compared between groups. Results The percentage change of ROI-ADCmean at a cutoff value of &gt;20 had excellent discrimination of responders versus nonresponders, while the percentage change of WL-ADCmean, ADCmin, and ADCmax at cutoff values of &gt;12.5, &gt;35.8, and &gt; 19.6 had acceptable discrimination of responders versus nonresponders. Logistic regression analysis revealed that only baseline WL ADCmin was a statistically significant independent predictor of response. Cancer cervix patients with baseline ADCmin &lt; or equal to 0.73 have 12.1 times higher odds of exhibiting a response. Conclusions The percentage change of ROI-ADCmean and WL histogram ADCmean values after concurrent chemoradiotherapy can predict response. Pretreatment WL histogram ADCmin was a statistically significant independent predictor of posttherapy response.

Abstract 4135873: Time Course of Late Gadolinium Enhancement Intensity in Ventricular Myocardium after Proton Beam Irradiation in Swine

Background: Proton beam irradiation to the ventricular myocardium may enable non-invasive targeting of ventricular tachycardia. Previous work has demonstrated the feasibility of imaging ablation lesion with late gadolinium enhanced (LGE) cardiac magnetic resonance imaging (MRI). Hypothesis: We hypothesize that proton beam irradiation will lead to progressively increasing density of LGE corresponding to lesion formation during follow-up after treatment delivery. Aim: The aim of the current study was to determine the time course of LGE intensity in ventricular myocardium following proton beam therapy. Methods: Eleven swine were irradiated with 40 Gy proton beam in the anterior or lateral left ventricular (LV) followed by LGE cardiac MRI every 4 weeks for up to 24 weeks. After manual contouring of the endocardial and epicardial myocardium, a region of interest (ROI) in the area irradiated with 0-5 Gy was contoured (remote ROI). The mean and standard deviation (SD) of the signal intensity (SI) of the remote ROI were calculated. Light LGE was defined as voxels with SI &gt; mean+2SD but &lt; mean+3SD of the remote ROI, while voxels with SI &gt; mean+3SD of the remote ROI were classified as having dense LGE. Voxels identified as bright due to image artifacts or noise were manually removed. The analysis was conducted in a fashion blinded to swine ID and time point after irradiation. Results: A total of 33 time points were analyzed (3.1 ± 1.4 MRI studies per swine). Figure 1A shows a representative time course of LGE in the same swine, progressing from diffuse light LGE at 8 weeks to dense LGE at 16-24 weeks. Figure 1B demonstrates the proportion of light versus dense LGE across timepoints in irradiated myocardial regions. At 8 weeks, light and dense LGE areas were evenly distributed. At 12 to 24 weeks, dense LGE increased to approximately 75%. The proportion of dense versus light LGE was significantly higher at 12, 16, and 24 weeks, as compared to 8 weeks. Conclusion: In ventricular myocardium, diffuse light LGE evident at 8 weeks progresses to denser LGE at 12-24 weeks following proton beam irradiation corresponding with lesion formation.

Age-related volume decrease in subcortical gray matter is a part of healthy brain aging in men.

With the global population aging, the number of individuals over 60 is expected to double by 2050. Brain volume increases until age 13, stabilizes between 18 and 35, then declines by 0.2% annually. Magnetic resonance imaging (MRI) studies highlight significant gray matter atrophy, necessitating differentiation between normal aging and neurodegeneration. This study assessed the impact of aging on subcortical gray matter in healthy males to identify biomarkers of physiological aging. A retrospective study of 106 healthy males who underwent brain MRI from 2012 to 2016, divided into two age groups: younger and older than 35years. MRI scans were performed using a 3T machine, and volumetric analysis was conducted with VolBrain software. Subcortical gray matter volumes were compared between groups. The Shapiro-Wilk test evaluated normality. Student's t-test and Mann-Whitney U test were used for statistical analysis, with significance defined as p < 0.05. Total intracranial volume was comparable between age groups (p = 0.527). Significant volume reductions (p < 0.05) were observed in subcortical gray matter structures, including the nucleus accumbens, caudate nucleus, globus pallidus, putamen, thalamus, and ventral diencephalon, particularly on the right side in the elderly group. Subcortical gray matter volume in healthy males shows significant differences between older and younger individuals (p < 0.05), with asymmetrical reduction and certain structures on the right aging more rapidly. These findings are significant for distinguishing healthy aging from neurodegeneration.

A distributed brain response predicting the facial expression of acute nociceptive pain.

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge of the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression. We then applied a multivariate pattern analysis to the fMRI data to predict the facial expression of pain. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a facial expression of pain signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal or no overlap with other pain-relevant brain signatures associated with nociception, pain ratings, thermal pain aversiveness, or pain valuation. The FEPS may provide a distinctive functional characterization of the distributed cerebral response to nociceptive pain associated with the socio-communicative role of non-verbal pain expression. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation(s) predicted and their underlying function(s). Future studies should explore other pain-relevant manifestations and assess the specificity of the FEPS against simulated pain expressions and other types of aversive or emotional states.

A distributed brain response predicting the facial expression of acute nociceptive pain

Pain is a private experience observable through various verbal and non-verbal behavioural manifestations, each of which may relate to different pain-related functions. Despite the importance of understanding the cerebral mechanisms underlying those manifestations, there is currently limited knowledge of the neural correlates of the facial expression of pain. In this functional magnetic resonance imaging (fMRI) study, noxious heat stimulation was applied in healthy volunteers and we tested if previously published brain signatures of pain were sensitive to pain expression. We then applied a multivariate pattern analysis to the fMRI data to predict the facial expression of pain. Results revealed the inability of previously developed pain neurosignatures to predict the facial expression of pain. We thus propose a facial expression of pain signature (FEPS) conveying distinctive information about the brain response to nociceptive stimulations with minimal or no overlap with other pain-relevant brain signatures associated with nociception, pain ratings, thermal pain aversiveness, or pain valuation. The FEPS may provide a distinctive functional characterization of the distributed cerebral response to nociceptive pain associated with the socio-communicative role of non-verbal pain expression. This underscores the complexity of pain phenomenology by reinforcing the view that neurosignatures conceived as biomarkers must be interpreted in relation to the specific pain manifestation(s) predicted and their underlying function(s). Future studies should explore other pain-relevant manifestations and assess the specificity of the FEPS against simulated pain expressions and other types of aversive or emotional states.