Osteosarcoma-targeted Cu and Ce based oxide nanoplatform for NIR II fluorescence/magnetic resonance dual-mode imaging and ros cascade amplification along with immunotherapy.

BACKGROUND: As the lethal bone tumor, osteosarcoma often frequently occurs in children and adolescents with locally destructive and high metastasis. Distinctive kinds of nanoplatform with high therapeutical effect and precise diagnosis for osteosarcoma are urgently required. Multimodal optical imaging and programmed treatment, including synergistic photothermal-chemodynamic therapy (PTT-CDT) elicits immunogenetic cell death (ICD) is a promising strategy that possesses high bio-imaging sensitivity for accurate osteosarcoma delineating as well as appreciable therapeutic efficacy with ignorable side-effects. METHODS AND RESULTS: In this study, mesoporous Cu and Ce based oxide nanoplatform with Arg-Gly-Asp (RGD) anchoring is designed and successfully constructed. After loading with indocyanine green, this nanoplatform can be utilized for precisely targeting and efficaciously ablating against osteosarcoma via PTT boosted CDT and the closely following ICD stimulation both in vitro and in vivo. Besides, it provides off-peak fluorescence bio-imaging in the second window of near-infrared region (NIR II, 1000-1700 nm) and Magnetic resonance signal, serves as the dual-mode contrast agents for osteosarcoma tissue discrimination. CONCLUSION: Tumor targeted Cu&Ce based mesoporous nanoplatform permits efficient osteosarcoma suppression and dual-mode bio-imaging that opens new possibility for effectively diagnosing and inhibiting the clinical malignant osteosarcoma.

Nuclei-specific hypothalamus networks predict a dimensional marker of stress in humans.

The hypothalamus is part of the hypothalamic-pituitary-adrenal axis which activates stress responses through release of cortisol. It is a small but heterogeneous structure comprising multiple nuclei. In vivo human neuroimaging has rarely succeeded in recording signals from individual hypothalamus nuclei. Here we use human resting-state fMRI (n = 498) with high spatial resolution to examine relationships between the functional connectivity of specific hypothalamic nuclei and a dimensional marker of prolonged stress. First, we demonstrate that we can parcellate the human hypothalamus into seven nuclei in vivo. Using the functional connectivity between these nuclei and other subcortical structures including the amygdala, we significantly predict stress scores out-of-sample. Predictions use 0.0015% of all possible brain edges, are specific to stress, and improve when using nucleus-specific compared to whole-hypothalamus connectivity. Thus, stress relates to connectivity changes in precise and functionally meaningful subcortical networks, which may be exploited in future studies using interventions in stress disorders.

The enhanced connectivity between the frontoparietal, somatomotor network and thalamus as the most significant network changes of chronic low back pain.

The prolonged duration of chronic low back pain (cLBP) inevitably leads to changes in the cognitive, attentional, sensory and emotional processing brain regions. Currently, it remains unclear how these alterations are manifested in the interplay between brain functional and structural networks. This study aimed to predict the Oswestry Disability Index (ODI) in cLBP patients using multimodal brain magnetic resonance imaging (MRI) data and identified the most significant features within the multimodal networks to aid in distinguishing patients from healthy controls (HCs). We constructed dynamic functional connectivity (dFC) and structural connectivity (SC) networks for all participants (n = 112) and employed the Connectome-based Predictive Modeling (CPM) approach to predict ODI scores, utilizing various feature selection thresholds to identify the most significant network change features in dFC and SC outcomes. Subsequently, we utilized these significant features for optimal classifier selection and the integration of multimodal features. The results revealed enhanced connectivity among the frontoparietal network (FPN), somatomotor network (SMN) and thalamus in cLBP patients compared to HCs. The thalamus transmits pain-related sensations and emotions to the cortical areas through the dorsolateral prefrontal cortex (dlPFC) and primary somatosensory cortex (SI), leading to alterations in whole-brain network functionality and structure. Regarding the model selection for the classifier, we found that Support Vector Machine (SVM) best fit these significant network features. The combined model based on dFC and SC features significantly improved classification performance between cLBP patients and HCs (AUC=0.9772). Finally, the results from an external validation set support our hypotheses and provide insights into the potential applicability of the model in real-world scenarios. Our discovery of enhanced connectivity between the thalamus and both the dlPFC (FPN) and SI (SMN) provides a valuable supplement to prior research on cLBP.

Altered brain morphology and functional connectivity in postmenopausal women: automatic segmentation of whole-brain and thalamic subnuclei and resting-state fMRI.

The transition to menopause is associated with various physiological changes, including alterations in brain structure and function. However, menopause-related structural and functional changes are poorly understood. The purpose of this study was not only to compare the brain volume changes between premenopausal and postmenopausal women, but also to evaluate the functional connectivity between the targeted brain regions associated with structural atrophy in postmenopausal women. Each 21 premenopausal and postmenopausal women underwent magnetic resonance imaging (MRI). T1-weighted MRI and resting-state functional MRI data were used to compare the brain volume and seed-based functional connectivity, respectively. In statistical analysis, multivariate analysis of variance, with age and whole brain volume as covariates, was used to evaluate surface areas and subcortical volumes between the two groups. Postmenopausal women showed significantly smaller cortical surface, especially in the left medial orbitofrontal cortex (mOFC), right superior temporal cortex, and right lateral orbitofrontal cortex, compared to premenopausal women (p < 0.05, Bonferroni-corrected) as well as significantly decreased functional connectivity between the left mOFC and the right thalamus was observed (p < 0.005, Monte-Carlo corrected). Although postmenopausal women did not show volume atrophy in the right thalamus, the volume of the right pulvinar anterior, which is one of the distinguished thalamic subnuclei, was significantly decreased (p < 0.05, Bonferroni-corrected). Taken together, our findings suggest that diminished brain volume and functional connectivity may be linked to menopause-related symptoms caused by the lower sex hormone levels.

Neural correlates of the addictions neuroclinical assessment (ANA) incentive salience factor among individuals with alcohol use disorder.

The Addictions Neuroclinical Assessment (ANA) is a recently-developed framework offering a more holistic understanding of three neurofunctional and behavioral domains that reflect the neurobiological dysfunction seen in alcohol use disorder (AUD). While the ANA domains have been well-validated across independent laboratories, there is a critical need to identify neural markers that subserve the proposed neurofunctional domains. The current study involves secondary data analysis of a two-week experimental medication trial of ibudilast (50 mg BID). Forty-five non-treatment-seeking participants with AUD (17F / 28 M) completed a battery of validated behavioral assessments forming the basis of their incentive salience factor score, computed via factor analysis, as well as a functional neuroimaging (fMRI) task assessing their neural reactivity to visual alcohol cues after being on placebo or ibudilast for 7 days. General linear models were conducted to examine the relationship between incentive salience and neural alcohol cue-reactivity in the ventral and dorsal stratum. Whole-brain generalized linear model analyses were conducted to examine associations between neural alcohol cue-reactivity and incentive salience. Age, sex, medication, and smoking status were included as covariates. Incentive salience was not associated with cue-elicited activation in the dorsal or ventral striatum. Incentive salience was significantly positively correlated (p < 0.05) with alcohol cue-elicited brain activation in reward-learning and affective regions including the insula and posterior cingulate cortices, bilateral precuneus, and bilateral precentral gyri. The ANA incentive salience factor is reflected in brain circuitry important for reward learning and emotion processing. Identifying a sub-phenotype of AUD characterized by increased incentive salience to alcohol cues allows for precision medicine approaches, i.e. treatments specifically targeting craving and reward from alcohol use. This study serves as a preliminary bio-behavioral validation for the incentive salience factor of the ANA. Further studies validating the neural correlates of other ANA factors, as well as replication in larger samples, appear warranted.

Reduced sleep quality defines a subtype of obsessive-compulsive disorder with lower Glx levels in the resting thalamus and worse response inhibition.

BACKGROUND: The aim of this study was to investigate the differences between resting and active thalamic neurometabolite levels and inhibitory function in obsessive compulsive disorder (OCD) patients with poor sleep quality (PSQ was defined as Pittsburgh Sleep Quality Index >5 and sleep efficiency ≤85%) compared to OCD patients with good sleep quality (GSQ) and healthy controls (HCs), as well as the relationship of these indices to obsessive compulsive symptoms. METHODS: Functional magnetic resonance spectroscopy (fMRS) was used to measure resting and active thalamic neurometabolite levels in 72 subjects (20 HCs and 38 OCD patients included in study analysis). Response inhibition function was measured by the Go-Nogo task before and during MRS recording. Subjective sleep quality was assessed using the Pittsburgh Sleep Quality Index (PSQI). The symptoms of OCD, anxiety and depression were evaluated using relevant clinical scales. RESULTS: OCD patients exhibited significantly reduced Glx/Cr levels in the resting thalamus. The levels of resting thalamic Glu/Cr and Glx/Cr in OCD patients with PSQ were significantly lowest. OCD patients had significantly lower correct rates on Go tasks, higher error rates on Nogo tasks, and longer error average response times (EART) to the Nogo task. OCD patients with PSQ demonstrated the highest Nogo task error rate and the longest EART to Nogo task. Furthermore, PSQI scores exhibited negative correlations with Glu/Cr and Glx/Cr in the resting thalamus. CONCLUSION: OCD patients with PSQ demonstrated reduced levels of thalamic resting Glx and more pronounced response inhibitory function impairment. Aberrant neurometabolite levels in critical brain regions, coupled with heightened response inhibition function deficits, may be a neurobiological basis for the PSQ that OCD patients generally exhibit.

Enhanced amygdala-anterior cingulate white matter structural connectivity in Sahaja Yoga Meditators.

OBJECTIVE: To study the white matter connections between anterior cingulate cortex, anterior insula and amygdala as key regions of the frontal-limbic network that have been related to meditation. DESIGN: Twenty experienced practitioners of Sahaja Yoga Meditation and twenty nonmeditators matched on age, gender and education level, were scanned using Diffusion Weighted Imaging, using a 3T scanner, and their white matter connectivity was compared using diffusion tensor imaging analyses. RESULTS: There were five white matter fiber paths in which meditators showed a larger number of tracts, two of them connecting the same area in both hemispheres: the left and right amygdalae and the left and right anterior insula; and the other three connecting left anterior cingulate with the right anterior insula, the right amygdala and the left amygdala. On the other hand, non-meditators showed larger number of tracts in two paths connecting the left anterior insula with the left amygdala, and the left anterior insula with the left anterior cingulate. CONCLUSIONS: The study shows that long-term practice of Sahaja Yoga Meditation is associated with larger white matter tracts strengthening interhemispheric connections between limbic regions and connections between cingulo-amygdalar and cingulo-insular brain regions related to top-down attentional and emotional processes as well as between top-down control functions that could potentially be related to the witness state perceived through the state of mental silence promoted with this meditation. On the other hand, reduced connectivity strength in left anterior insula in the meditation group could be associated to reduced emotional processing affecting top-down processes.

Computational Fractal-Based Analysis of MR Susceptibility-Weighted Imaging (SWI) in Neuro-Oncology and Neurotraumatology.

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique able to depict the magnetic susceptibility produced by different substances, such as deoxyhemoglobin, calcium, and iron. The main application of SWI in clinical neuroimaging is detecting microbleedings and venous vasculature. Quantitative analyses of SWI have been developed over the last few years, aimed to offer new parameters, which could be used as neuroimaging biomarkers. Each technique has shown pros and cons, but no gold standard exists yet. The fractal dimension (FD) has been investigated as a novel potential objective parameter for monitoring intratumoral space-filling properties of SWI patterns. We showed that SWI patterns found in different tumors or different glioma grades can be represented by a gradient in the fractal dimension, thereby enabling each tumor to be assigned a specific SWI fingerprint. Such results were especially relevant in the differentiation of low-grade versus high-grade gliomas, as well as from high-grade gliomas versus lymphomas.Therefore, FD has been suggested as a potential image biomarker to analyze intrinsic neoplastic architecture in order to improve the differential diagnosis within clinical neuroimaging, determine appropriate therapy, and improve outcome in patients.These promising preliminary findings could be extended into the field of neurotraumatology, by means of the application of computational fractal-based analysis for the qualitative and quantitative imaging of microbleedings in traumatic brain injury patients. In consideration of some evidences showing that SWI signals are correlated with trauma clinical severity, FD might offer some objective prognostic biomarkers.In conclusion, fractal-based morphometrics of SWI could be further investigated to be used in a complementary way with other techniques, in order to form a holistic understanding of the temporal evolution of brain tumors and follow-up response to treatment, with several further applications in other fields, such as neurotraumatology and cerebrovascular neurosurgery as well.

"sCT-Feasibility" - a feasibility study for deep learning-based MRI-only brain radiotherapy.

BACKGROUND: Radiotherapy (RT) is an important treatment modality for patients with brain malignancies. Traditionally, computed tomography (CT) images are used for RT treatment planning whereas magnetic resonance imaging (MRI) images are used for tumor delineation. Therefore, MRI and CT need to be registered, which is an error prone process. The purpose of this clinical study is to investigate the clinical feasibility of a deep learning-based MRI-only workflow for brain radiotherapy, that eliminates the registration uncertainty through calculation of a synthetic CT (sCT) from MRI data. METHODS: A total of 54 patients with an indication for radiation treatment of the brain and stereotactic mask immobilization will be recruited. All study patients will receive standard therapy and imaging including both CT and MRI. All patients will receive dedicated RT-MRI scans in treatment position. An sCT will be reconstructed from an acquired MRI DIXON-sequence using a commercially available deep learning solution on which subsequent radiotherapy planning will be performed. Through multiple quality assurance (QA) measures and reviews during the course of the study, the feasibility of an MRI-only workflow and comparative parameters between sCT and standard CT workflow will be investigated holistically. These QA measures include feasibility and quality of image guidance (IGRT) at the linear accelerator using sCT derived digitally reconstructed radiographs in addition to potential dosimetric deviations between the CT and sCT plan. The aim of this clinical study is to establish a brain MRI-only workflow as well as to identify risks and QA mechanisms to ensure a safe integration of deep learning-based sCT into radiotherapy planning and delivery. DISCUSSION: Compared to CT, MRI offers a superior soft tissue contrast without additional radiation dose to the patients. However, up to now, even though the dosimetrical equivalence of CT and sCT has been shown in several retrospective studies, MRI-only workflows have still not been widely adopted. The present study aims to determine feasibility and safety of deep learning-based MRI-only radiotherapy in a holistic manner incorporating the whole radiotherapy workflow. TRIAL REGISTRATION: NCT06106997.

No replication of direct neuronal activity-related (DIANA) fMRI in anesthetized mice.

Direct imaging of neuronal activity (DIANA) by functional magnetic resonance imaging (fMRI) could be a revolutionary approach for advancing systems neuroscience research. To independently replicate this observation, we performed fMRI experiments in anesthetized mice. The blood oxygenation level-dependent (BOLD) response to whisker stimulation was reliably detected in the primary barrel cortex before and after DIANA experiments; however, no DIANA-like fMRI peak was observed in individual animals' data with the 50 to 300 trials. Extensively averaged data involving 1050 trials in six mice showed a flat baseline and no detectable neuronal activity-like fMRI peak. However, spurious, nonreplicable peaks were found when using a small number of trials, and artifactual peaks were detected when some outlier-like trials were excluded. Further, no detectable DIANA peak was observed in the BOLD-responding thalamus from the selected trials with the neuronal activity-like reference function in the barrel cortex. Thus, we were unable to replicate the previously reported results without data preselection.

Validation of real-time fMRI neurofeedback procedure for cognitive training using counterbalanced active-sham study design.

Investigation of neural mechanisms of real-time functional MRI neurofeedback (rtfMRI-nf) training requires an efficient study control approach. A common rtfMRI-nf study design involves an experimental group, receiving active rtfMRI-nf, and a control group, provided with sham rtfMRI-nf. We report the first study in which rtfMRI-nf procedure is controlled through counterbalancing training runs with active and sham rtfMRI-nf for each participant. Healthy volunteers (n = 18) used rtfMRI-nf to upregulate fMRI activity of an individually defined target region in the left dorsolateral prefrontal cortex (DLPFC) while performing tasks that involved mental generation of a random numerical sequence and serial summation of numbers in the sequence. Sham rtfMRI-nf was provided based on fMRI activity of a different brain region, not involved in these tasks. The experimental procedure included two training runs with the active rtfMRI-nf and two runs with the sham rtfMRI-nf, in a randomized order. The participants achieved significantly higher fMRI activation of the left DLPFC target region during the active rtfMRI-nf conditions compared to the sham rtfMRI-nf conditions. fMRI functional connectivity of the left DLPFC target region with the nodes of the central executive network was significantly enhanced during the active rtfMRI-nf conditions relative to the sham conditions. fMRI connectivity of the target region with the nodes of the default mode network was similarly enhanced. fMRI connectivity changes between the active and sham conditions exhibited meaningful associations with individual performance measures on the Working Memory Multimodal Attention Task, the Approach-Avoidance Task, and the Trail Making Test. Our results demonstrate that the counterbalanced active-sham study design can be efficiently used to investigate mechanisms of active rtfMRI-nf in direct comparison to those of sham rtfMRI-nf. Further studies with larger group sizes are needed to confirm the reported findings and evaluate clinical utility of this study control approach.

Increased Thalamic Connectivity in Juvenile Myoclonic Epilepsy Based on Electroencephalography Source-Level Analysis.

Background: This study investigated alterations in the intrinsic thalamic network of patients with juvenile myoclonic epilepsy (JME) based on an electroencephalography (EEG) source-level analysis. Materials and Methods: We enrolled patients newly diagnosed with JME as well as healthy controls. The assessments were conducted in the resting state. We computed sources based on the scalp electrical potentials using a minimum-norm imaging method and a standardized, low-resolution, brain electromagnetic tomography approach. To create a functional connectivity matrix, we used the Talairach atlas to define thalamic nodes and applied the coherence method to measure brain synchronization as edges. We then calculated the intrinsic thalamic network using graph theory. We compared the intrinsic thalamic network of patients with JME with those of healthy controls. Results: This study included 67 patients with JME and 66 healthy controls. EEG source-level analysis revealed significant differences in the intrinsic thalamic networks between patients with JME and healthy controls. The measures of functional connectivity (radius, diameter, and characteristic path length) were significantly lower in patients with JME than in healthy controls (radius: 2.769 vs. 3.544, p = 0.015; diameter: 4.464 vs. 5.443, p = 0.024; and characteristic path length: 2.248 vs. 2.616, p = 0.046). Conclusions: We demonstrated alterations in the intrinsic thalamic network in patients with JME compared with those in healthy controls based on the EEG source-level analysis. These findings indicated increased thalamic connectivity in the JME group. These intrinsic thalamic network changes may be related to the pathophysiology of JME.

3.0-T MR-guided transgluteal in-bore-targeted prostate biopsy under local anesthesia in patients without rectal access: a single-institute experience and review of literature.

PURPOSE: To describe the technique and evaluate the performance of MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia in patients without rectal access. METHODS: Ten men (mean age, 69 (range 57-86) years) without rectal access underwent 13 MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia. All patients underwent mp-MRI at our institute prior to biopsy. Three patients had prior US-guided transperineal biopsy which was unsuccessful in one, negative in one, and yielded GG1 (GS6) PCa in one. Procedure time, complications, histopathology result, and subsequent management were recorded. RESULTS: Median interval between rectal surgery and presentation with elevated PSA was 12.5 years (interquartile range (IQR) 25-75, 8-36.5 years). Mean PSA was 11.9 (range, 4.8 -59.0) ng/ml and PSA density was 0.49 (0.05 -3.2) ng/ml/ml. Distribution of PI-RADS v2.0/2.1 scores of the targeted lesions were PI-RADS 5-3; PI-RADS 4-6; and PI-RADS 3-1. Mean lesion size was 1.5 cm (range, 1.0-3.6 cm). Median interval between MRI and biopsy was 5.5 months (IQR 25-75, 1.5-9 months). Mean procedure time was 47.4 min (range, 29-80 min) and the number of cores varied between 3 and 5. Of the 13 biopsies, 4 yielded clinically significant prostate cancer (csPca), with a Gleason score ≥ 7, 1 yielded insignificant prostate cancer (Gleason score = 6), 7 yielded benign prostatic tissue, and one was technically unsuccessful. 3/13 biopsies were repeat biopsies which detected csPCa in 2 out of the 3 patients. None of the patients had biopsy-related complication. Biopsy result changed management to radiation therapy with ADT in 2 patients with the rest on active surveillance. CONCLUSION: MRI-guided transgluteal in-bore-targeted biopsy of the prostate gland under local anesthesia is feasible in patients without rectal access.

Beyond boundaries: investigating shared and divergent connectivity in the pre-/postcentral gyri and supplementary motor area.

OBJECTIVE: This study aimed to comprehensively investigate the functional connectivity of key brain regions involved in motor and sensory functions, namely the precentral gyrus, postcentral gyrus and supplementary motor area (SMA). Using advanced MRI, the objective was to understand the neurophysiological integrative characterizations of these regions by examining their connectivity with eight distinct functional brain networks. The goal was to uncover their roles beyond conventional motor and sensory functions, contributing to a more holistic understanding of brain functioning. METHODS: The study involved 198 healthy volunteers, with the primary methodology being functional connectivity analysis using advanced MRI techniques. The bilateral precentral gyrus, postcentral gyrus and SMA served as seed regions, and their connectivity with eight distinct brain regional functional networks was investigated. This approach allowed for the exploration of synchronized activity between these critical brain areas, shedding light on their integrated functioning and relationships with other brain networks. RESULTS: The study revealed a nuanced landscape of functional connectivity for the precentral gyrus, postcentral gyrus and SMA with the main functional brain networks. Despite their high functional connectedness, these regions displayed diverse functional integrations with other networks, particularly in the salience, visual, cerebellar and language networks. Specific data and statistical significance were not provided in the abstract, but the results suggested unique and distinct roles for each brain area in sophisticated cognitive tasks beyond their conventional motor and sensory functions. CONCLUSION: The study emphasized the multifaceted roles of the precentral gyrus, postcentral gyrus and SMA. Beyond their crucial involvement in motor and sensory functions, these regions exhibited varied functional integrations with different brain networks. The observed disparities, especially in the salience, visual, cerebellar and language networks, indicated a nuanced and specialized involvement of these regions in diverse cognitive functions. The study underscores the importance of considering the broader neurophysiological landscape to comprehend the intricate roles of these brain areas, contributing to ongoing efforts in unraveling the complexities of brain function.

Usefulness of fat-containing agents: an initial study on estimating fat content for magnetic resonance imaging.

This initial study aimed at testing whether fat-containing agents can be used for the fat mass estimation methods using magnetic resonance imaging (MRI). As an example for clinical application, fat-containing agents (based on soybean oil, 10% and 20%), 100% soybean oil, and saline as reference substances were placed outside the proximal femurs obtained from 14 participants and analyzed by 0.3 T MRI. Fat content was the estimated fat fraction (FF) based on signal intensity (SIeFF, %). The SIeFF values of the femoral bone marrow, including the femoral head, neck, shaft, and trochanter area, were measured. MRI data were compared in terms of bone mineral content (BMC) and bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) in the proximal femur. Twelve pig femurs were also used to confirm the correlation between FF by the DIXON method and SIeFF. According to Pearson's correlation coefficient, the SIeFF and total BMC and BMD data revealed strong and moderate negative correlations in the femoral head (r < - 0.74) and other sites (r = - 0.66 to - 0.45). FF and SIeFF showed a strong correlation (r = 0.96). This study was an initial investigation of a method for estimating fat mass with fat-containing agents and showed the potential for use in MRI. SIeFF and FF showed a strong correlation, and SIeFF and BMD and BMC showed correlation; however, further studies are needed to use SIeFF as a substitute for DXA.

Segmenting hypothalamic subunits in human newborn magnetic resonance imaging data.

Preclinical evidence suggests that inter-individual variation in the structure of the hypothalamus at birth is associated with variation in the intrauterine environment, with downstream implications for future disease susceptibility. However, scientific advancement in humans is limited by a lack of validated methods for the automatic segmentation of the newborn hypothalamus. N = 215 healthy full-term infants with paired T1-/T2-weighted MR images across four sites were considered for primary analyses (mean postmenstrual age = 44.3 ± 3.5 weeks, nmale /nfemale = 110/106). The outputs of FreeSurfer's hypothalamic subunit segmentation tools designed for adults (segFS) were compared against those of a novel registration-based pipeline developed here (segATLAS) and against manually edited segmentations (segMAN) as reference. Comparisons were made using Dice Similarity Coefficients (DSCs) and through expected associations with postmenstrual age at scan. In addition, we aimed to demonstrate the validity of the segATLAS pipeline by testing for the stability of inter-individual variation in hypothalamic volume across the first year of life (n = 41 longitudinal datasets available). SegFS and segATLAS segmentations demonstrated a wide spread in agreement (mean DSC = 0.65 ± 0.14 SD; range = {0.03-0.80}). SegATLAS volumes were more highly correlated with postmenstrual age at scan than segFS volumes (n = 215 infants; RsegATLAS 2 = 65% vs. RsegFS 2 = 40%), and segATLAS volumes demonstrated a higher degree of agreement with segMAN reference segmentations at the whole hypothalamus (segATLAS DSC = 0.89 ± 0.06 SD; segFS DSC = 0.68 ± 0.14 SD) and subunit levels (segATLAS DSC = 0.80 ± 0.16 SD; segFS DSC = 0.40 ± 0.26 SD). In addition, segATLAS (but not segFS) volumes demonstrated stability from near birth to ~1 years age (n = 41; R2 = 25%; p < 10-3 ). These findings highlight segATLAS as a valid and publicly available (https://github.com/jerodras/neonate_hypothalamus_seg) pipeline for the segmentation of hypothalamic subunits using human newborn MRI up to 3 months of age collected at resolutions on the order of 1 mm isotropic. Because the hypothalamus is traditionally understudied due to a lack of high-quality segmentation tools during the early life period, and because the hypothalamus is of high biological relevance to human growth and development, this tool may stimulate developmental and clinical research by providing new insight into the unique role of the hypothalamus and its subunits in shaping trajectories of early life health and disease.

A brief real-time fNIRS-informed neurofeedback training of the prefrontal cortex changes brain activity and connectivity during subsequent working memory challenge.

Working memory (WM) represents a building-block of higher cognitive functions and a wide range of mental disorders are associated with WM impairments. Initial studies have shown that several sessions of functional near-infrared spectroscopy (fNIRS) informed real-time neurofeedback (NF) allow healthy individuals to volitionally increase activity in the dorsolateral prefrontal cortex (DLPFC), a region critically involved in WM. For the translation to therapeutic or neuroenhancement applications, however, it is critical to assess whether fNIRS-NF success transfers into neural and behavioral WM enhancement in the absence of feedback. We therefore combined single-session fNIRS-NF of the left DLPFC with a randomized sham-controlled design (N = 62 participants) and a subsequent WM challenge with concomitant functional MRI. Over four runs of fNIRS-NF, the left DLPFC NF training group demonstrated enhanced neural activity in this region, reflecting successful acquisition of neural self-regulation. During the subsequent WM challenge, we observed no evidence for performance differences between the training and the sham group. Importantly, however, examination of the fMRI data revealed that - compared to the sham group - the training group exhibited significantly increased regional activity in the bilateral DLPFC and decreased left DLPFC - left anterior insula functional connectivity during the WM challenge. Exploratory analyses revealed a negative association between DLPFC activity and WM reaction times in the NF group. Together, these findings indicate that healthy individuals can learn to volitionally increase left DLPFC activity in a single training session and that the training success translates into WM-related neural activation and connectivity changes in the absence of feedback. This renders fNIRS-NF as a promising and scalable WM intervention approach that could be applied to various mental disorders.

Annual mpMRI surveillance: PI-RADS upgrading and increasing trend correlated with patients who harbor clinically significant disease.

INTRODUCTION: Prostate cancer screening has routinely identified men with very low- or low-risk disease, per the National Comprehensive Cancer Network guidelines. Current literature has demonstrated that the most appropriate management strategy for these patients is active surveillance (AS). The mainstay of AS includes periodic biopsies and biannual prostate-specific antigen tests. However, multiparametric magnetic resonance imaging (mpMRI) is uniquely posed to improve patient surveillance. This study aimed to evaluate the utility of an annual mpMRI in patients on AS, focusing on radiologic upgrading and Prostate Imaging-Reporting and Data System (PI-RADS) trends as indicators of clinically significant disease. METHODS: This prospective, single intuition, study enrolled 208 patients on AS who had at least two biopsies and 1 mpMRI with a median follow-up of 5.03 years. The main outcome variable was time to Gleason grade (GG) reclassification. RESULTS: After delineating patients on their initial PI-RADS score, men with score 3 and 5 lesions at first MRI had comparable GG reclassification-free survival to their counterparts. Conversely, men with initial PI-RADS 4 lesions showed a lower 5-year GG reclassification-free survival compared to those with PI-RADS score 1-2. The cohort was then subset to 70 patients who obtained ≥2 mpMRIs on protocol. Men experiencing uptrending mpMRI scores had an increased risk of GG reclassification, with a 35.4% difference in 5 year GG reclassification-free survival probability on the Kaplan-Meier curve analysis. CONCLUSION: In conclusion, this study demonstrates that for men on AS with stable recapitulated disease, an annual MRI may replace repeat biopsies after confirmatory sampling has been obtained. On the other hand, men who initiate AS with PI-RADS 4 and/or who display uptrending mpMRI scores require periodic biopsies along with repeat imaging. This study highlights the utility of integrating an annual MRI into AS protocols, thus promising a more effective approach to management.

Phosphorus-31: A table-top method for 3D B1-field amplitude and phase measurements.

A novel method of high-spatial-resolution, 3D B1-field distribution measurements is presented. The method is independent of the MR-scanner, and it allows for automated acquisitions of complete maps of all magnetic field vector components for both proton and heteronuclear MR coils of arbitrary geometrical shapes. The advantage of the method proposed here, compared with methods based on measurements with an MR-scanner, is that a complete image of both receive and transmit B1-fields, including the phase of the B1-field, can be acquired. The B1 field maps obtained in this manner can be used for absolute quantification of metabolites in MRS experiments, as well as for intensity compensations in imaging experiments, both of which are important concepts in biological and medical MR applications. Another use might be in coil development and testing. A comparison with B1 field magnitude maps obtained with an MR-scanner was included to validate the accuracy of the proposed method.

MRI in Adult Patients with Active and Inactive Implanted MR-conditional, MR-nonconditional, and Other Devices.

Active implanted medical devices (AIMDs) enable therapy and patient monitoring by way of electrical activity and typically have a battery and electrical leads. The most common types of AIMDs include cardiac implantable electronic devices (CIEDs), spinal cord stimulators, deep brain stimulators, bone growth or fusion stimulators, other neurostimulators, and drug infusion pumps. As more patients with AIMDs undergo MRI, it is important to consider the safety of patients who have these implanted devices during MRI. The authors review the physics concepts related to MRI safety, such as peak spatial gradient magnetic field, specific absorption rate, root mean square value of the effective magnetic component of the transmitted RF pulse, and gradient slew rate, as well as the parameters necessary to remain within safety limits. The roles of MRI safety personnel, as set forth by the International Society of Magnetic Resonance in Medicine, are emphasized. In addition, the relevant information provided in vendor manuals is reviewed, with a focus on how to obtain relevant up-to-date information. The radiologist should be able to modify protocols to meet safety requirements, address possible alternatives to MRI, and weigh the potential benefits of MRI against the potential risks. A few more advanced topics, such as fractured or abandoned device leads and patients with multiple implanted medical devices, also are addressed. Recommended workflows for MRI in patients with implanted medical devices are outlined. It is important to implement an algorithmic MRI safety process, including a review of the MRI safety information; patient screening; optimal imaging; and monitoring patients before, during, and after the examination. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material. See the invited commentary by Shetty et al in this issue.