Magnetic Resonance Imaging Studies Research Articles

Medial prefrontal neuroplasticity during extended-release naltrexone treatment of opioid use disorder – a longitudinal structural magnetic resonance imaging study

Opioid use disorder (OUD) has been linked to macroscopic structural alterations in the brain. The monthly injectable, extended-release formulation of μ-opioid antagonist naltrexone (XR-NTX) is highly effective in reducing opioid craving and preventing opioid relapse. Here, we investigated the neuroanatomical effects of XR-NTX by examining changes in cortical thickness during treatment for OUD. Forty-seven OUD patients underwent structural magnetic resonance imaging and subjectively rated their opioid craving ≤1 day before (pre-treatment) and 11 ± 3 days after (on-treatment) the first XR-NTX injection. A sample of fifty-six non-OUD individuals completed a single imaging session and served as the comparison group. A publicly available [¹¹C]carfentanil positron emission tomography dataset was used to assess the relationship between changes in cortical thickness and μ-opioid receptor (MOR) binding potential across brain regions. We found that the thickness of the medial prefrontal and anterior cingulate cortices (mPFC/aCC; regions with high MOR binding potential) was comparable between the non-OUD individuals and the OUD patients at pre-treatment. However, among the OUD patients, mPFC/aCC thickness significantly decreased from pre-treatment to on-treatment. A greater reduction in mPFC/aCC thickness was associated with a greater reduction in opioid craving. Taken together, our study suggests XR-NTX-induced cortical thickness reduction in the mPFC/aCC regions in OUD patients. The reduction in thickness does not appear to indicate a restoration to the non-OUD level but rather reflects XR-NTX’s distinct therapeutic impact on an MOR-rich brain structure. Our findings highlight the neuroplastic effects of XR-NTX that may inform the development of novel OUD interventions.

Imaging Findings and MRI Patterns in a Cohort of 18q Chromosomal Abnormalities.

The abnormalities of the long arm of chromosome 18 (18q) constitute a complex spectrum. We aimed to systematically analyze their MR imaging features. We hypothesized that there would be variable but recognizable white matter and structural patterns in this cohort. In this retrospective cohort study, we included pediatric patients with a proved abnormality of 18q between 2000-2022. An age- and sex-matched control cohort was also constructed. Thirty-six cases, median MR imaging age 19.6 months (4.3-59.3), satisfied our inclusion criteria. Most were female (25, 69%, F:M ratio 2.2:1). Fifty MR imaging studies were analyzed, and 35 (70%) had delayed myelination. Two independent readers scored brain myelination with excellent interrater reliability. Three recognizable evolving MR imaging patterns with distinct age distributions and improving myelination scores were identified: Pelizaeus-Merzbacher disease-like (9.9 months, 37), intermediate (22 months, 48), and washed-out pattern (113.6 months, 53). Etiologically, MRIs were analyzed across 3 subgroups: 18q deletion (34, 69%), trisomy 18 (10, 21%), and ring chromosome 18 (5, 10%). Ring chromosome 18 had the highest myelination lag (27, P = .005) and multifocal white matter changes (P = .001). Trisomy 18 had smaller pons and cerebellar dimensions (anteposterior diameter pons, P = .002; corpus callosum vermis, P < .001; and transverse cerebellar diameter, P = .04). In this cohort of 18q chromosomal abnormalities, MR imaging revealed recognizable patterns correlating with improving brain myelination. Imaging findings appear to be on a continuum with more severe white matter abnormalities in ring chromosome 18 and greater prevalence of structural abnormalities of the pons and cerebellum in trisomy 18.

Age and sex-related differences in T1 and T2 mapping. 1.5 magnetic resonance referent values

Introduction: Parametric mapping is a non-invasive method to quantify tissue changes in the myocardium by measuring T1, T2 and T2* relaxation times and extracellular volume, requiring a pre-established range of normal values. Purpose: To establish reference values for native T1 and T2 myocardial relaxation times in healthy subjects on 1.5 T magnetic resonance imaging and to assess changes in their values according to left ventricular segments, age, sex, heart rate, and myocardial thickness. Material and Methods: A prospective 1.5 T magnetic resonance imaging study was performed with the voluntary participation of 50 healthy individuals in different age groups. Image analysis was performed by a radiologist with 5 years of experience in the field of CMRT and further coordinated with a radiologist with more than 20 years of expe-rience in the field. Siemens ARGUS integrated software was used to calculate the volumes and function of both cameras. Global and segmental T1 and T2 values were measured in the shortaxis midlevel section by manually delineating the region of interest. Myocardial thickness of the mid septum was measured for each patient. Results: The distribution of volunteers was 25 men and 25 women. Significantly higher global T1 values were observed in women (1027.7 &amp;plusmn; 25.4 ms) compared to men (992.9 &amp;plusmn; 24.4 ms), at p &lt; 0.001. The same correlation was observed in individual segments, with a significant difference between genders. Examination of the correlation between T1 and other parameters demonstrated a negative linear relationship only with myocardial thickness. Global T2 in women (48.6 &amp;plusmn; 2.49 ms) was also significantly higher than in men (44.6 &amp;plusmn; 2.06 ms), with an observed difference of 3.95, p &lt; 0.001. Global T2 showed a very strong negative correlation with myocardial thickness (r = -0.769; p &lt; 0.001). There was no sig-nificant correlation between T2 times and heart rate and age of patients. Conclusion: A statistically significant difference in native T1 and T2 values by sex was demonstrated. The use of sex-specific reference values to distinguish healthy from pathologically affected myocardium is recommended.

Bibliometric analysis of global research trends in magnetic resonance imaging studies of substantia nigra in Parkinson's disease (2001-2024).

Parkinson's disease (PD) is a globally prevalent neurodegenerative disorder, primarily characterized by muscle rigidity, resting tremor, and bradykinesia. The incidence of PD is rapidly escalating worldwide. Numerous studies have been conducted on the application of magnetic resonance imaging (MRI) in investigating the substantia nigra (SN) in PD patients. However, to date, no bibliometric analysis has been performed on this specific research area. Therefore, this study aimed to provide a comprehensive analysis of the current status in MRI research on the SN in PD patients. MRI study records related to the SN in PD patients from 2001 to 2024 were searched by using the Web of Science Core Collection (WOSCC) database and then the CiteSpace and VOSviewer were used to conduct bibliometric analysis. Our analysis found that the number of published articles related studies on MRI of the SN in PD showed an overall upward trend over the past decade, in which Lehericy, Stephane, Du, Guangwei, and Huang, Xuemei are the top three authors with the most articles. Additionally, United States, China and Germany are the main contributors to MRI studies of SN in PD. And Shanghai Jiao Tong University, University of Florida and Seoul National University are the leading institutions in the field. Finally, the keyword analysis showed that the hotspots and trends of research in this field are mainly concentrated in quantitative susceptibility mapping, neuroimaging, and neuromelanin-sensitive MRI. These analysis identified the most influential authors, institutions, countries and research hotspots in the field of SN-MRI research in PD, which has reference significance for the research interest in this field and provides a new idea for PD prevention.

Differential activation of lateral parabrachial nuclei and their limbic projections during head compared with body pain: A 7-Tesla functional magnetic resonance imaging study

Pain is a complex experience that involves sensory, emotional, and motivational components. It has been suggested that pain arising from the head and orofacial regions evokes stronger emotional responses than pain from the body. Indeed, recent work in rodents reports different patterns of activation in ascending pain pathways during noxious stimulation of the skin of the face when compared to noxious stimulation of the body. Such differences may dictate different activation patterns in higher brain regions, specifically in those areas processing the affective component of pain. We aimed to use ultra-high field functional magnetic resonance imaging (fMRI at 7-Tesla) to determine whether noxious thermal stimuli applied to the surface of the face and body evoke differential activation patterns within the ascending pain pathway in awake humans (n=16). Compared to the body, noxious heat stimulation to the face evoked more widespread signal changes in prefrontal cortical regions and numerous brainstem and subcortical limbic areas. Moreover, facial pain evoked significantly different signal changes in the lateral parabrachial nucleus, substantia nigra, paraventricular hypothalamus, and paraventricular thalamus, to those evoked by body pain. These results are consistent with recent preclinical findings of differential activation in the brainstem and subcortical limbic nuclei and associated cortices during cutaneous pain of the face when compared with the body. The findings suggest one potential mechanism by which facial pain could evoke a greater emotional impact than that evoked by body pain.

White matter microstructure and functional connectivity in the brains of infants with Turner syndrome.

Turner syndrome, caused by complete or partial loss of an X-chromosome, is often accompanied by specific cognitive challenges. Magnetic resonance imaging studies of adults and children with Turner syndrome suggest these deficits reflect differences in anatomical and functional connectivity. However, no imaging studies have explored connectivity in infants with Turner syndrome. Consequently, it is unclear when in development connectivity differences emerge. To address this gap, we compared functional connectivity and white matter microstructure of 1-year-old infants with Turner syndrome to typically developing 1-year-old boys and girls. We examined functional connectivity between the right precentral gyrus and five regions that show reduced volume in 1-year old infants with Turner syndrome compared to controls and found no differences. However, exploratory analyses suggested infants with Turner syndrome have altered connectivity between right supramarginal gyrus and left insula and right putamen. To assess anatomical connectivity, we examined diffusivity indices along the superior longitudinal fasciculus and found no differences. However, an exploratory analysis of 46 additional white matter tracts revealed significant group differences in nine tracts. Results suggest that the first year of life is a window in which interventions might prevent connectivity differences observed at later ages, and by extension, some of the cognitive challenges associated with Turner syndrome.

The Incidence of Injuries to Ramp Semimembranosus Complex Lesions After ACL Injury: An MRI Study

Background: Medial meniscal ramp lesions have recently been an area of interest because of their recognized prevalence in association with anterior cruciate ligament (ACL) ruptures. Anatomically, the medial meniscal ramp is composed of the meniscocapsular ligament in continuity with the semimembranosus muscle and the meniscotibial ligament. Diagnosis of ramp semimembranosus complex (RSC) injuries remains challenging, and their prevalence is likely to be underestimated in comparison with ramp lesions. Purpose: To determine the prevalence of RSC lesions after a complete ACL rupture. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A retrospective database analysis was performed. The cohort consisted of the first 100 patients with complete ACL rupture confirmed by magnetic resonance imaging (MRI) who underwent knee arthroscopy for ACL reconstruction in 2019. The semimembranosus lesions were identified using MRI by 2 independent radiologists specializing in musculoskeletal imaging. The ramp lesions were initially diagnosed using MRI and then confirmed during arthroscopy by an experienced knee surgeon. The magnitude of rotatory instability was recorded using the pivot-shift test. A multivariate analysis was used to determine the lesions associated with the semimembranosus complex. Results: Of 100 patients, 53 showed lesions of the RSC; among them, 30 ramp lesions were confirmed after arthroscopic evaluation, and 40 semimembranosus lesions (23 without ramp lesion and 17 with ramp lesion) were found using MRI. A positive pivot shift was present in 57% of patients with combined RSC injury ( P = .04) compared with 36% in patients without an RSC lesion. Conclusion: Lesions of the RSC were found in more than half of ACL ruptures in this retrospective cohort. Rotational instability could be associated with combined ACL and RSC injury.

Exploring the Utility of a Functional Magnetic Resonance Imaging (fMRI) Cannabis Cue-Reactivity Paradigm in Treatment Seeking Adults with Cannabis Use Disorder

Functional magnetic resonance imaging (fMRI) studies examining cue-reactivity in cannabis use disorder (CUD) have either had small sample sizes or involved non-treatment-seeking participants. As a secondary analysis, we administered an fMRI cue-reactivity task to CUD participants entering two separate clinical trials (varenicline or repetitive Transcranial Magnetic Stimulation-rTMS) to determine the task activation patterns for treatment-seeking participants with CUD. We aimed to determine the activation patterns for the total sample and determined behavioral correlates. We additionally compared studies to determine if patterns were consistent. Treatment-seeking participants with moderate or severe CUD had behavioral craving measured at baseline via the short form of the Marijuana Craving Questionnaire (MCQ-SF) and completed a visual cannabis cue-reactivity task during fMRI (measuring the Blood-Oxygen-Level-Dependent-BOLD response) following 24-hours of cannabis-abstinence. Sixty-five participants were included (37-varenicline, 28-rTMS; 32% female; mean-age 30.4±9.9SD). When contrasting cannabis-images vs. matched-neutral-images, participants showed greater BOLD response in bilateral ventromedial-prefrontal, dorsolateral-prefrontal, anterior cingulate, and visual cortices, as well as the striatum. There was stronger task-based functional-connectivity (tbFC) between the medial prefrontal cortex and both the amygdala and the visual cortex. Craving negatively correlated with BOLD response in the left ventral striatum (R2=-0.32; p=0.01) in the full sample. There were no significant differences in either activation or tbFC between studies. Among two separate treatment-seeking groups with CUD, there was increased cannabis cue-reactivity and tbFC in regions related to executive function and reward processing. Cannabis-craving was negatively associated with cue-reactivity in the left ventral striatum.

Neural Basis of Pain Empathy Dysregulations in Mental Disorders – A Pre-registered Neuroimaging Meta-Analysis

Pain empathy represents a fundamental building block of several social functions, which have been demonstrated to be impaired across various mental disorders by accumulating evidence from case-control functional magnetic resonance imaging (fMRI) studies. However, it remains unclear whether the dysregulations are underpinned by robust neural alterations across mental disorders. This study utilized coordinate-based meta-analyses to quantitatively determine robust markers of altered pain empathy across mental disorders. To support the interpretation of the findings exploratory network-level and behavioral meta-analyses were conducted. Quantitative analysis of eleven case-control fMRI studies with data from 296 patients and 229 controls revealed patients with mental disorders exhibited increased pain empathic reactivity in the left anterior cingulate gyrus, adjacent medial prefrontal cortex, and right middle temporal gyrus, yet decreased activity in the left cerebellum IV/V and left middle occipital gyrus compared to controls. The hyperactive regions showed network-level interactions with the core default mode network (DMN) and were associated with affective and social cognitive domains. The findings suggest that pain-empathic alterations across mental disorders are underpinned by excessive empathic reactivity in brain systems involved in empathic distress and social processes, highlighting a shared therapeutic target to normalize basal social dysfunctions in mental disorders.

Dynamic functional network connectivity in children with profound bilateral congenital sensorineural hearing loss.

Functional magnetic resonance imaging (fMRI) studies have revealed extensive functional reorganization in patients with sensorineural hearing loss (SNHL). However, almost no study focuses on the dynamic functional connectivity after hearing loss. This study aimed to investigate dynamic functional connectivity changes in children with profound bilateral congenital SNHL under the age of 3years. Thirty-two children with profound bilateral congenital SNHL and 24 children with normal hearing were recruited for the present study. Independent component analysis identified 18 independent components composing five resting-state networks. A sliding window approach was used to acquire dynamic functional matrices. Three states were identified using the k-means algorithm. Then, the differences in temporal properties and the variance of network efficiency between groups were compared. The children with SNHL showed longer mean dwell time and decreased functional connectivity between the auditory network and sensorimotor network in state 3 (P < 0.05), which was characterized by relatively stronger functional connectivity between high-order resting-state networks and motion and perception networks. There was no difference in the variance of network efficiency. These results indicated the functional reorganization due to hearing loss. This study also provided new perspectives for understanding the state-dependent connectivity patterns in children with SNHL.

A postmortem high-resolution MRI study of the development of cochlear nerve-related structures in the second and third trimesters of pregnancy.

Magnetic resonance imaging (MRI) is used to determine whether cochlear nerve development is normal in infants and adults, but it has not yet been used to evaluate cochlear nerve development or measure cochlear nerve-related structures in the fetus. This study sought to provide imaging data for clinical evaluations concerning cochlear nerve development in the fetus using MRI. Postmortem 3.0-Tesla MRI of inner ear was performed in 51 fetuses with normal temporal bones at 25 to 40 weeks of gestation. The continuous scanning protocol incorporated axial three-dimensional (3D) sampling perfection with application-specific contrasts using different flip angle evolution sequences. The images were evaluated to measure the structures of the cochlear aperture (CA), internal auditory canal (IAC), and vestibulocochlear and facial nerves in the cerebellopontine angle (CPA), which have been reported to be associated with cochlear nerve development. We also calculated the ratio between the diameters of the vestibulocochlear and facial nerves. The measurable parameters were compared between the right and left sides. The threshold for statistical significance was set at P<0.05. The inner ear anatomy was discernible on MRI in all the fetal specimens, and growth of the CA, IAC, vestibulocochlear nerve, and facial nerve in the CPA was observed as fetal age increased. There was no significant difference in the measurements of these structures between the right and left sides (all P>0.05). MRI can be used to help evaluate the anatomy and development of the cochlear nerve in the fetus. These normative measurements could be valuable for clinical evaluations of the cochlear nerve.

Development of fetal magnetic resonance imaging (MRI) phantom.

Anthropomorphic phantoms play an important role in routine clinical practice. They can be used to calibrate magnetic resonance imaging (MRI) scanners, control the diagnostic equipment quality, and reduce the acquisition time. The latter is especially critical for diagnosing fetal anomalies, which requires optimal image quality within the shortest possible time. This paper aims to develop an MRI fetal phantom and determine the materials that best mimic the magnetic resonance (MR) characteristics of its internal organs. Future phantom features will include simulations of fetal limb movements. A single MRI study of a pregnant woman at 20 weeks 3 days of gestation was used as a reference and for image segmentation. Anonymized Digital Imaging and Communication in Medicine (DICOM) files were imported into 3D Slicer v. 5.2.1 for segmentation of the uterus, fetus, and internal organs. Based on the performed segmentation, a three-dimensional model was obtained for printing on a 3D printer. The mold was 3D printed on an Anycubic Photon M3 Max printer. The paper showcases the selection and manufacturing of compositions to simulate the relaxation times of the fetal organs. Formulations for emulsions and carrageenan- and agar-based hydrogels are presented. The selected compositions were used to fill the 3D printed model. Statistical analysis showed no significant differences in absolute and relative signal values obtained from scans of a pregnant woman at 20 weeks and 3 days and a fetal phantom. During the study, an anthropomorphic fetal phantom was constructed, filled with compositions with relaxation times T1 and T2 similar to the control values of the corresponding tissues. The phantom can be used to set up and optimize fetal MRI protocols, train and educate medical students, residents, graduate students, and X-ray technicians, as well as to timely control image quality and equipment serviceability.

Quantitative modeling of the emergence of macroscopic grid-like representations.

When subjects navigate through spatial environments, grid cells exhibit firing fields that are arranged in a triangular grid pattern. Direct recordings of grid cells from the human brain are rare. Hence, functional magnetic resonance imaging (fMRI) studies proposed an indirect measure of entorhinal grid-cell activity, quantified as hexadirectional modulation of fMRI activity as a function of the subject's movement direction. However, it remains unclear how the activity of a population of grid cells may exhibit hexadirectional modulation. Here, we use numerical simulations and analytical calculations to suggest that this hexadirectional modulation is best explained by head-direction tuning aligned to the grid axes, whereas it is not clearly supported by a bias of grid cells toward a particular phase offset. Firing-rate adaptation can result in hexadirectional modulation, but the available cellular data is insufficient to clearly support or refute this option. The magnitude of hexadirectional modulation furthermore depends considerably on the subject's navigation pattern, indicating that future fMRI studies could be designed to test which hypothesis most likely accounts for the fMRI measure of grid cells. Our findings also underline the importance of quantifying the properties of human grid cells to further elucidate how hexadirectional modulations of fMRI activity may emerge.

White Matter Correlates of Cognition: A Diffusion Magnetic Resonance Imaging Study

BackgroundOur comprehension of the interplay of cognition and the brain remains constrained. While functional imaging studies have identified cognitive brain regions, structural correlates of cognitive functions remain underexplored. Advanced methods like Diffusion Magnetic Resonance Imaging (DMRI) facilitate the exploration of brain connectivity and White Matter (WM) tract microstructure. Therefore, we conducted connectometry method on DMRI data, to reveal WM tracts associated with cognition. Methods125 healthy participants from the National Institute of Mental Health Intramural Healthy Volunteer Dataset were recruited. Multiple regression analyses were conducted between DMRI-derived Quantitative Anisotropy (QA) values within WM tracts and scores of participants in Flanker Inhibitory Control and Attention Test (attention), Dimensional Change Card Sort (executive function), Picture Sequence Memory Test (episodic memory), and List Sorting Working Memory Test (working memory) tasks from National Institute of Health toolbox. The significance level was set at False Discovery Rate (FDR)<0.05. ResultsWe identified significant positive correlations between the QA of WM tracts within the left cerebellum and bilateral fornix with attention, executive functioning, and episodic memory (FDR=0.018, 0.0002, and 0.0002, respectively), and a negative correlation between QA of WM tracts within bilateral cerebellum with attention (FDR=0.028). Working memory demonstrated positive correlations with QA of left inferior longitudinal and left inferior fronto-occipital fasciculi (FDR=0.0009), while it showed a negative correlation with QA of right cerebellar tracts (FDR=0.0005). ConclusionOur results underscore the intricate link between cognitive performance and WM integrity in frontal, temporal, and cerebellar regions, offering insights into early detection and targeted interventions for cognitive disorders.

Reliability of quantitative magnetic susceptibility imaging metrics for cerebral cortex and major subcortical structures.

Susceptibility estimates derived from quantitative susceptibility mapping (QSM) images for the cerebral cortex and major subcortical structures are variably reported in brain magnetic resonance imaging (MRI) studies, as average of all ( ), absolute ( ), or positive- ( ) and negative-only ( ) susceptibility values using a region of interest (ROI) approach. This pilot study presents a reliability analysis of currently used ROI-QSM metrics and an alternative ROI-based approach to obtain voxel-weighted ROI-QSM metrics ( and ). Ten healthy subjects underwent repeated (test-retest) 3-dimensional multi-echo gradient-echo (3DMEGE) 3 Tesla MRI measurements. Complex-valued 3DMEGE images were acquired and reconstructed with slice thicknesses of 1 and 2mm (3DMEGE1, 3DMEGE2) along with 3DT1-weighted isometric (voxel 1 mm3) images for independent registration and ROI segmentation. Agreement, consistency, and reproducibility of ROI-QSM metrics were assessed through Bland-Altman analysis, intraclass correlation coefficient, and interscan and intersubject coefficient of variation (CoV). All ROI-QSM metrics exhibited good to excellent consistency and test-retest agreement with no proportional bias. Interscan CoV was higher for in comparison to the other metrics where it was below 15%, in both 3DMEGE1 and 3DMEGE2 datasets. Intersubject CoV for and exceeded 50% in all ROIs. Among the evaluated ROI-QSM metrics, and estimates were less reliable, whereas separating positive and negative values (using ) improved the reproducibility within, and the comparability between, subjects, even when reducing the slice thickness. These preliminary findings may offer valuable insights toward standardizing ROI-QSM metrics across different patient cohorts and imaging settings in future clinical MRI studies.

Painful stimulation increases functional connectivity between supplementary motor area and thalamus in patients with small fibre neuropathy.

The lead symptom of small fibre neuropathy (SFN) is neuropathic pain. Recent functional magnetic resonance imaging (fMRI) studies have indicated central changes in SFN patients of different etiologies. However, less is known about brain functional connectivity during acute pain processing in idiopathic SFN. We conducted fMRI with thermal heat pain application (left volar forearm) in 32 idiopathic SFN patients and 31 healthy controls. We performed functional connectivity analyses with right supplementary motor area (SMA), left insula, and left caudate nucleus (CN) as seed regions, respectively. Since pathogenic gain-of-function variants in voltage gated sodium channels (Nav) have been linked to SFN pathophysiology, explorative connectivity analyses were performed in a homogenous subsample of patients carrying rare heterozygous missense variants. For right SMA, we found significantly higher connectivity with the right thalamus in SFN patients compared to controls. This connectivity correlated significantly with intraepidermal nerve fibre density, suggesting a link between peripheral and central pain processing. We found significantly reduced connections between right SMA and right middle frontal gyrus in patients with Nav variants. Likewise, connectivity between left CN and right frontal pole was decreased. Aberrant functional connectivity in SFN is in line with previous research on other chronic pain syndromes. Functional connectivity changes may be linked to SFN, highlighting the need to determine if they result from peripheral changes causing abnormal somatosensory processing. This understanding may be crucial for assessing their impact on painful symptoms and therapy response. We found increased functional connectivity between SMA and thalamus during painful stimulation in patients with idiopathic SFN. Connectivity correlated significantly with intraepidermal nerve fibre density, suggesting a link between peripheral and central pain processing. Our findings emphasize the importance of investigating functional connectivity changes as a potential feature of SFN.

Effects of connectivity hyperalignment (CHA) on estimated brain network properties: from coarse-scale to fine-scale.

Recent gains in functional magnetic resonance imaging (fMRI) studies have been driven by increasingly sophisticated statistical and computational techniques and the ability to capture brain data at finer spatial and temporal resolution. These advances allow researchers to develop population-level models of the functional brain representations underlying behavior, performance, clinical status, and prognosis. However, even following conventional preprocessing pipelines, considerable inter-individual disparities in functional localization persist, posing a hurdle to performing compelling population-level inference. Persistent misalignment in functional topography after registration and spatial normalization will reduce power in developing predictive models and biomarkers, reduce the specificity of estimated brain responses and patterns, and provide misleading results on local neural representations and individual differences. This study aims to determine how connectivity hyperalignment (CHA)-an analytic approach for handling functional misalignment-can change estimated functional brain network topologies at various spatial scales from the coarsest set of parcels down to the vertex-level scale. The findings highlight the role of CHA in improving inter-subject similarities, while retaining individual-specific information and idiosyncrasies at finer spatial granularities. This highlights the potential for fine-grained connectivity analysis using this approach to reveal previously unexplored facets of brain structure and function.

Predicting treatment outcomes in major depressive disorder using brain magnetic resonance imaging: a meta-analysis.

Recent studies have provided promising evidence that neuroimaging data can predict treatment outcomes for patients with major depressive disorder (MDD). As most of these studies had small sample sizes, a meta-analysis is warranted to identify the most robust findings and imaging modalities, and to compare predictive outcomes obtained in magnetic resonance imaging (MRI) and studies using clinical and demographic features. We conducted a literature search from database inception to July 22, 2023, to identify studies using pretreatment clinical or brain MRI features to predict treatment outcomes in patients with MDD. Two meta-analyses were conducted on clinical and MRI studies, respectively. The meta-regression was employed to explore the effects of covariates and compare the predictive performance between clinical and MRI groups, as well as across MRI modalities and intervention subgroups. Meta-analysis of 13 clinical studies yielded an area under the curve (AUC) of 0.73, while in 44 MRI studies, the AUC was 0.89. MRI studies showed a higher sensitivity than clinical studies (0.78 vs. 0.62, Z = 3.42, P = 0.001). In MRI studies, resting-state functional MRI (rsfMRI) exhibited a higher specificity than task-based fMRI (tbfMRI) (0.79 vs. 0.69, Z = -2.86, P = 0.004). No significant differences in predictive performance were found between structural and functional MRI, nor between different interventions. Of note, predictive MRI features for treatment outcomes in studies using antidepressants were predominantly located in the limbic and default mode networks, while studies of electroconvulsive therapy (ECT) were restricted mainly to the limbic network. Our findings suggest a promise for pretreatment brain MRI features to predict MDD treatment outcomes, outperforming clinical features. While tasks in tbfMRI studies differed, those studies overall had less predictive utility than rsfMRI data. Overlapping but distinct network-level measures predicted antidepressants and ECT outcomes. Future studies are needed to predict outcomes using multiple MRI features, and to clarify whether imaging features predict outcomes generally or differ depending on treatments.

Feasibility of Brain Ultrasound Performed by Nurses in the Evaluation of Newborns Who Are HIV Exposed in Utero and Uninfected: A Pilot Study in Botswana.

Children who are exposed to HIV in utero but are uninfected (HIV-exposed uninfected or HEU) are at higher risk of neurodevelopmental delays compared to children born to persons without HIV. Magnetic resonance imaging (MRI) studies have revealed differences in grey matter volumes, cerebral perfusion, and white matter changes in these children. However, MRI is costly and not widely available in areas with high HIV prevalence, like Botswana, where more than 15% of children are HEU. To address this, we explored the use of brain ultrasound, conducted by trained study nurses, as a safe, less costly, and accurate alternative method for assessing differences relating to HIV exposure status in the brain structures of neonates. Brain ultrasounds of newborns in the Following Longitudinal Outcomes to Understand, Report, Intervene and Sustain Health for Infants, Children, Adolescents who are HIV Exposed Uninfected (FLOURISH) observational study-comprising 35 HEU newborns and 24 HIV-unexposed (HU) newborns-were performed by study nurses and evaluated by a pediatric radiologist for quality and structural abnormalities, such as calcifications, cysts, and hemorrhages. Two radiologists measured extra-axial cerebrospinal fluid spaces, ventricles, and the corpus callosum. Ultrasound studies of 59 newborns (59% boys; median gestational age 38.4 weeks) were completed. All studies were of diagnostic quality, with 90.2% rated as being of good or excellent quality. Structural abnormalities were rare (10.2% incidence) and did not differ by HIV exposure group. Corpus callosum length was shorter in HEU infants compared to HU infants (45.7 mm vs. 47.3 mm; p = 0.03). Other ventricular and corpus callosum measurements showed no significant variations. Brain ultrasounds conducted by study nurses are feasible and reveal differences in corpus callosum length between HEU and HU infants. The benefits of easier training, lower cost, and rapid deployment make ultrasound a promising screening tool in resource-limited settings.

The Etiology of Intracranial Artery Stenosis in Autoimmune Rheumatic Diseases-An Observational High-Resolution Magnetic Resonance Imaging Study.

Autoimmune rheumatic diseases (AIRD) can cause intracranial artery stenosis (ICAS) and lead to stroke. This study aimed to characterize patients with ICAS associated with AIRD. Utilizing data from a high-resolution magnetic resonance imaging (HRMRI) database, we retrospectively reviewed AIRD patients with ICAS. Stratification into vasculitis, atherosclerosis, and mixed athero-vasculitis subtypes was based on imaging findings, followed by a comparative analysis of clinical characteristics and outcomes across these subgroups. Among 139 patients (45.1±17.3 years; 64.7% females), 56 (40.3%) were identified with vasculitis, 57 (41.0%) with atherosclerosis, and 26 (18.7%) with mixed athero-vasculitis. The average interval from AIRD-onset to HRMRI was 5 years. Patients with vasculitis presented with a younger age of AIRD-onset (34.5±19.4 years), nearly ten years earlier than other groups (P=0.010), with a higher artery occlusion incidence (44.6% vs. 21.1% and 26.9%, P=0.021). Patients with atherosclerosis showed the highest cardiovascular risk factor prevalence (73.7% vs. 48.2% and 61.5%, P=0.021) but lower intracranial artery wall enhancement instances (63.2% vs. 100% in others, P<0.001). The mixed athero-vasculitis group, predominantly male (69.2% vs. 30.4% and 25.6%, P<0.001), exhibited the most arterial involvement (5 arteries per person vs. 3 and 2, P=0.001). Over an average 21-month follow-up, 23 (17.0%) patients experienced stroke events, and 8 (5.9%) died, with the mixed athero-vasculitis group facing the highest risk of stroke events (32.0%) and the highest mortality (12.0%). Intracranial arteries are injured and lead to heterogeneous disease courses when exposed to AIRD and cardiovascular risk factors. While atherosclerosis acceleration is common, vasculitis may further contribute to early-developed occlusion and multiple artery involvement. Varied intracranial arteriopathies may result in different outcomes. ICAS = intracranial artery stenosis; AIRD = Autoimmune rheumatic diseases; HRMRI = high-resolution magnetic resonance imaging.