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BMC Medical Imaging May 2024Magnetic Resonance Imaging (MRI)-based imaging techniques are useful for assessing white matter (WM) structural and microstructural integrity in the context of infection... (Review)
Review
BACKGROUND
Magnetic Resonance Imaging (MRI)-based imaging techniques are useful for assessing white matter (WM) structural and microstructural integrity in the context of infection and inflammation. The purpose of this scoping review was to assess the range of work on the use of WM neuroimaging approaches to understand the impact of congenital and perinatal viral infections or exposures on the developing brain.
METHODS
This scoping review was conducted according to the Arksey and O' Malley framework. A literature search was performed in Web of Science, Scopus and PubMed for primary research articles published from database conception up to January 2022. Studies evaluating the use of MRI-based WM imaging techniques in congenital and perinatal viral infections or exposures were included. Results were grouped by age and infection.
RESULTS
A total of 826 articles were identified for screening and 28 final articles were included. Congenital and perinatal infections represented in the included studies were cytomegalovirus (CMV) infection (n = 12), human immunodeficiency virus (HIV) infection (n = 11) or exposure (n = 2) or combined (n = 2), and herpes simplex virus (HSV) infection (n = 1). The represented MRI-based WM imaging methods included structural MRI and diffusion-weighted and diffusion tensor MRI (DWI/ DTI). Regions with the most frequently reported diffusion metric group differences included the cerebellar region, corticospinal tract and association fibre WM tracts in both children with HIV infection and children who are HIV-exposed uninfected. In qualitative imaging studies, WM hyperintensities were the most frequently reported brain abnormality in children with CMV infection and children with HSV infection.
CONCLUSION
There was evidence that WM imaging techniques can play a role as diagnostic and evaluation tools assessing the impact of congenital infections and perinatal viral exposures on the developing brain. The high sensitivity for identifying WM hyperintensities suggests structural brain MRI is a useful neurodiagnostic modality in assessing children with congenital CMV infection, while the DTI changes associated with HIV suggest metrics such as fractional anisotropy have the potential to be specific markers of subtle impairment or WM damage in neuroHIV.
Topics: Female; Humans; Infant; Infant, Newborn; Pregnancy; Brain; Cytomegalovirus Infections; Diffusion Tensor Imaging; HIV Infections; Magnetic Resonance Imaging; Neuroimaging; Pregnancy Complications, Infectious; Virus Diseases; White Matter
PubMed: 38783187
DOI: 10.1186/s12880-024-01282-9 -
Human Brain Mapping Jun 2024In this study we explore the spatio-temporal trajectory and clinical relevance of microstructural white matter changes within and beyond subcortical stroke lesions...
In this study we explore the spatio-temporal trajectory and clinical relevance of microstructural white matter changes within and beyond subcortical stroke lesions detected by free-water imaging. Twenty-seven patients with subcortical infarct with mean age of 66.73 (SD 11.57) and median initial NIHSS score of 4 (IQR 3-7) received diffusion MRI 3-5 days, 1 month, 3 months, and 12 months after symptom-onset. Extracellular free-water and fractional anisotropy of the tissue (FA) were averaged within stroke lesions and the surrounding tissue. Linear models showed increased free-water and decreased FA in the white matter of patients with subcortical stroke (lesion [free-water/FA, mean relative difference in %, ipsilesional vs. contralesional hemisphere at 3-5 days, 1 month, 3 months, and 12 months after symptom-onset]: +41/-34, +111/-37, +208/-26, +251/-18; perilesional tissue [range in %]: +[5-24]/-[0.2-7], +[2-20]/-[3-16], +[5-43]/-[2-16], +[10-110]/-[2-12]). Microstructural changes were most prominent within the lesion and gradually became less pronounced with increasing distance from the lesion. While free-water elevations continuously increased over time and peaked after 12 months, FA decreases were most evident 1 month post-stroke, gradually returning to baseline values thereafter. Higher perilesional free-water and higher lesional FA at baseline were correlated with greater reductions in lesion size (rho = -0.51, p = .03) in unadjusted analyses only, while there were no associations with clinical measures. In summary, we find a characteristic spatio-temporal pattern of extracellular and cellular alterations beyond subcortical stroke lesions, indicating a dynamic parenchymal response to ischemia characterized by vasogenic edema, cellular damage, and white matter atrophy.
Topics: Humans; Male; Aged; Female; Middle Aged; Ischemic Stroke; White Matter; Diffusion Magnetic Resonance Imaging; Longitudinal Studies; Water; Brain; Anisotropy
PubMed: 38780442
DOI: 10.1002/hbm.26722 -
Parkinsonism & Related Disorders May 2024Identifying biomarkers reflecting cellular dysfunctions in early Parkinson's disease patients (ePD) is needed to develop targeted therapeutic strategies. We aimed to...
INTRODUCTION
Identifying biomarkers reflecting cellular dysfunctions in early Parkinson's disease patients (ePD) is needed to develop targeted therapeutic strategies. We aimed to determine if cellular energetic dysfunction related to increased brain sodium concentration would be co-located to microstructural alterations and iron deposition in ePD.
METHODS
We prospectively included 12 ePD (mean disease duration 20.0 ± 10.2 months) and 13 healthy controls (HC), scanned with a 7 T H and Na MRI. Complementary voxel-based and region-based assessments were performed, the latter utilizing a high-resolution multimodal template we created (combining quantitative T maps (qT1), transverse relaxation rate (R2*), quantitative magnetic susceptibility mapping (QSM) images) from 200 subjects. This template allowed a precise multiparametric assessment of sodium concentration, QSM, R*, qT, mean diffusivity, and fractional anisotropy values. A two-sided p-value<0.05 was considered statistically significant after the Bonferroni correction.
RESULTS
Relative to HC, ePD showed significantly higher sodium concentration in left Substantia nigra (SN) pars reticulata (46.13 mM ± 3.52 vs 38.60 mM ± 6.10, p = 0.038), a subpart of the SN pars compacta (SNc) and ventral tegmental area, Putamen, Globus Pallidum external, accumbens nucleus and claustrum. Significantly increased QSM and R2* values, and decreased T values, were limited to the Nigrosomes 1 (Nig) and right SNc (all p < 0.05). QSM values in the Nig were significantly correlated to UPDRS-III scores (r = 0.91,p < 0.001).
CONCLUSION
In ePD, brain sodium accumulation was broad and dissociated from iron accumulation. As with iron accumulation, a sodium-related pathophysiological approach could lead to identifying potential new therapeutic agents and deserves further investigation.
PubMed: 38776725
DOI: 10.1016/j.parkreldis.2024.106996 -
Journal of Athletic Training May 2024Structural evidence for corticospinal tract (CST) abnormality between patients with ACLR and healthy controls, and the relationships between CST structure and clinical...
CONTEXT
Structural evidence for corticospinal tract (CST) abnormality between patients with ACLR and healthy controls, and the relationships between CST structure and clinical features of the patients (e.g., objective sensorimotor outcomes, postoperative duration) are lacking.
OBJECTIVES
To investigate whether the structural features of CST 1) differ between patients with ACLR and healthy controls, and 2) were associated with clinical features in patients following ACLR.
DESIGN
Cross-sectional study.
SETTING
Sports medicine laboratory.
PATIENTS OR OTHER PARTICIPANTS
Twenty-six patients who had undergone ACLR and twenty-six healthy controls were enrolled in this cross-sectional investigation.
MAIN OUTCOME MEASURE(S)
Using the CST as the region of interest, we performed diffusion tensor imaging to measure the microstructure of white matter tracts. Between-group comparisons and correlation analyses with clinical features in patients with ACLR were performed.
RESULTS
The patients with ACLR showed significant, moderate lower fractional anisotropy (FA, Cohen's d = -0.666, 95% CIs -1.221 to -0.104), lower axial diffusivity (AD, Cohen's d = -0.526, 95% CIs -1.077 to 0.030), and higher radial diffusivity (RD, Cohen's d = 0.514, 95% CIs -0.042 to 1.064) when compared to that of healthy controls, with the RD values being significantly correlated with the postoperative duration (r = 0.623, p < 0.001) after controlling the age, sex, and BMI in patients with ACLR.
CONCLUSIONS
This study revealed that patients with ACLR have impaired integrity (lower FA values and higher RD values) in the CST contralateral to the ACLR injured limb in comparison with healthy controls. Decreased integrity (higher RD) of the CST in patients was significantly associated with longer postoperative duration, which hinted that impaired structural integrity of the CST may be a maladaptive process of neuroplasticity in ACLR.
PubMed: 38775129
DOI: 10.4085/1062-6050-0380.23 -
Brain and Behavior May 2024Using correlation tractography, this study aimed to find statistically significant correlations between white matter (WM) tracts in participants with obstructive sleep...
INTRODUCTION
Using correlation tractography, this study aimed to find statistically significant correlations between white matter (WM) tracts in participants with obstructive sleep apnea (OSA) and OSA severity. We hypothesized that changes in certain WM tracts could be related to OSA severity.
METHODS
We enrolled 40 participants with OSA who underwent diffusion tensor imaging (DTI) using a 3.0 Tesla MRI scanner. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), and quantitative anisotropy (QA)-values were used in the connectometry analysis. The apnea-hypopnea index (AHI) is a representative measure of the severity of OSA. Diffusion MRI connectometry that was used to derive correlational tractography revealed changes in the values of FA, MD, AD, RD, and QA when correlated with the AHI. A false-discovery rate threshold of 0.05 was used to select tracts to conduct multiple corrections.
RESULTS
Connectometry analysis revealed that the AHI in participants with OSA was negatively correlated with FA values in WM tracts that included the cingulum, corpus callosum, cerebellum, inferior longitudinal fasciculus, fornices, thalamic radiations, inferior fronto-occipital fasciculus, superior and posterior corticostriatal tracts, medial lemnisci, and arcuate fasciculus. However, there were no statistically significant results in the WM tracts, in which FA values were positively correlated with the AHI. In addition, connectometry analysis did not reveal statistically significant results in WM tracts, in which MD, AD, RD, and QA values were positively or negatively correlated with the AHI.
CONCLUSION
Several WM tract changes were correlated with OSA severity. However, WM changes in OSA likely involve tissue edema and not neuronal changes, such as axonal loss. Connectometry analyses are valuable tools for detecting WM changes in sleep disorders.
Topics: Humans; Sleep Apnea, Obstructive; Diffusion Tensor Imaging; Male; Female; Middle Aged; Adult; White Matter; Severity of Illness Index; Brain
PubMed: 38773829
DOI: 10.1002/brb3.3541 -
BioRxiv : the Preprint Server For... May 2024Magnetic resonance elastography (MRE) is a promising neuroimaging technique to probe tissue microstructure, which has revealed widespread softening with loss of...
Magnetic resonance elastography (MRE) is a promising neuroimaging technique to probe tissue microstructure, which has revealed widespread softening with loss of structural integrity in the aging brain. Traditional MRE approaches assume mechanical isotropy. However, white matter is known to be anisotropic from aligned, myelinated axonal bundles, which can lead to uncertainty in mechanical property estimates in these areas when using isotropic MRE. Recent advances in anisotropic MRE now allow for estimation of shear and tensile anisotropy, along with substrate shear modulus, in white matter tracts. The objective of this study was to investigate age-related differences in anisotropic mechanical properties in human brain white matter tracts for the first time. Anisotropic mechanical properties in all tracts were found to be significantly lower in older adults compared to young adults, with average property differences ranging between 0.028-0.107 for shear anisotropy and between 0.139-0.347 for tensile anisotropy. Stiffness perpendicular to the axonal fiber direction was also significantly lower in older age, but only in certain tracts. When compared with fractional anisotropy measures from diffusion tensor imaging, we found that anisotropic MRE measures provided additional, complementary information in describing differences between the white matter integrity of young and older populations. Anisotropic MRE provides a new tool for studying white matter structural integrity in aging and neurodegeneration.
PubMed: 38766139
DOI: 10.1101/2024.05.08.593260 -
PloS One 2024White matter (WM) changes occur throughout the lifespan at a different rate for each developmental period. We aggregated 10879 structural MRIs and 6186...
White matter (WM) changes occur throughout the lifespan at a different rate for each developmental period. We aggregated 10879 structural MRIs and 6186 diffusion-weighted MRIs from participants between 2 weeks to 100 years of age. Age-related changes in gray matter and WM partial volumes and microstructural WM properties, both brain-wide and on 29 reconstructed tracts, were investigated as a function of biological sex and hemisphere, when appropriate. We investigated the curve fit that would best explain age-related differences by fitting linear, cubic, quadratic, and exponential models to macro and microstructural WM properties. Following the first steep increase in WM volume during infancy and childhood, the rate of development slows down in adulthood and decreases with aging. Similarly, microstructural properties of WM, particularly fractional anisotropy (FA) and mean diffusivity (MD), follow independent rates of change across the lifespan. The overall increase in FA and decrease in MD are modulated by demographic factors, such as the participant's age, and show different hemispheric asymmetries in some association tracts reconstructed via probabilistic tractography. All changes in WM macro and microstructure seem to follow nonlinear trajectories, which also differ based on the considered metric. Exponential changes occurred for the WM volume and FA and MD values in the first five years of life. Collectively, these results provide novel insight into how changes in different metrics of WM occur when a lifespan approach is considered.
Topics: Humans; White Matter; Adult; Male; Female; Adolescent; Middle Aged; Aged; Young Adult; Child; Aged, 80 and over; Infant; Child, Preschool; Aging; Longevity; Infant, Newborn; Diffusion Tensor Imaging; Diffusion Magnetic Resonance Imaging; Anisotropy; Brain; Gray Matter
PubMed: 38758830
DOI: 10.1371/journal.pone.0301520 -
Annals of Clinical and Translational... Jun 2024Alzheimer's disease (AD) and cerebral small vessel disease (cSVD), the two most common causes of dementia, are characterized by white matter (WM) alterations diverging...
OBJECTIVE
Alzheimer's disease (AD) and cerebral small vessel disease (cSVD), the two most common causes of dementia, are characterized by white matter (WM) alterations diverging from the physiological changes occurring in healthy aging. Diffusion tensor imaging (DTI) is a valuable tool to quantify WM integrity non-invasively and identify the determinants of such alterations. Here, we investigated main effects and interactions of AD pathology, APOE-ε4, cSVD, and cardiovascular risk on spatial patterns of WM alterations in non-demented older adults.
METHODS
Within the prospective European Prevention of Alzheimer's Dementia study, we selected 606 participants (64.9 ± 7.2 years, 376 females) with baseline cerebrospinal fluid samples of amyloid β and p-Tau and MRI scans, including DTI scans. Longitudinal scans (mean follow-up time = 1.3 ± 0.5 years) were obtained in a subset (n = 223). WM integrity was assessed by extracting fractional anisotropy and mean diffusivity in relevant tracts. To identify the determinants of WM disruption, we performed a multimodel inference to identify the best linear mixed-effects model for each tract.
RESULTS
AD pathology, APOE-ε4, cSVD burden, and cardiovascular risk were all associated with WM integrity within several tracts. While limbic tracts were mainly impacted by AD pathology and APOE-ε4, commissural, associative, and projection tract integrity was more related to cSVD burden and cardiovascular risk. AD pathology and cSVD did not show any significant interaction effect.
INTERPRETATION
Our results suggest that AD pathology and cSVD exert independent and spatially different effects on WM microstructure, supporting the role of DTI in disease monitoring and suggesting independent targets for preventive medicine approaches.
Topics: Humans; Alzheimer Disease; Female; Cerebral Small Vessel Diseases; Male; White Matter; Aged; Diffusion Tensor Imaging; Middle Aged; Amyloid beta-Peptides; Apolipoprotein E4; tau Proteins; Prospective Studies
PubMed: 38757392
DOI: 10.1002/acn3.52071 -
Frontiers in Neurology 2024To explore the effectiveness of diffusion quantitative parameters derived from advanced diffusion models in detecting brain microstructural changes in patients with...
OBJECTIVES
To explore the effectiveness of diffusion quantitative parameters derived from advanced diffusion models in detecting brain microstructural changes in patients with chronic kidney disease (CKD).
METHODS
The study comprised 44 CKD patients (eGFR<59 mL/min/1.73 m) and 35 age-and sex-matched healthy controls. All patients underwent diffusion spectrum imaging (DSI) and conventional magnetic resonance imaging. Reconstructed to obtain diffusion MRI models, including diffusion tensor imaging (DTI), neurite orientation dispersion and density imaging (NODDI) and Mean Apparent Propagator (MAP)-MRI, were processed to obtain multi-parameter maps. The Tract-Based Spatial Statistics (TBSS) analysis was utilized for detecting microstructural differences and Pearson correlation analysis assessed the relationship between renal metabolism markers and diffusion parameters in the brain regions of CKD patients. Receiver operating characteristic (ROC) curve analysis assessed the diagnostic performance of diffusion models, with AUC comparisons made using DeLong's method.
RESULTS
Significant differences were noted in DTI, NODDI, and MAP-MRI parameters between CKD patients and controls ( < 0.05). DTI indicated a decrease in Fractional Anisotropy(FA) and an increase in Mean and Radial Diffusivity (MD and RD) in CKD patients. NODDI indicated decreased Intracellular and increased Extracellular Volume Fractions (ICVF and ECVF). MAP-MRI identified extensive microstructural changes, with elevated Mean Squared Displacement (MSD) and Q-space Inverse Variance (QIV) values, and reduced Non-Gaussianity (NG), Axial Non-Gaussianity (NGAx), Radial Non-Gaussianity (NGRad), Return-to-Origin Probability (RTOP), Return-to-Axis Probability (RTAP), and Return-to-Plane Probability (RTPP). There was a moderate correlation between serum uric acid (SUA) and diffusion parameters in six brain regions ( < 0.05). ROC analysis showed the AUC values of DTI_FA ranged from 0.70 to 0.793. MAP_NGAx in the Retrolenticular part of the internal capsule R reported a high AUC value of 0.843 ( < 0.05), which was not significantly different from other diffusion parameters ( > 0.05).
CONCLUSION
The advanced diffusion models (DTI, NODDI, and MAP-MRI) are promising for detecting brain microstructural changes in CKD patients, offering significant insights into CKD-affected brain areas.
PubMed: 38751882
DOI: 10.3389/fneur.2024.1387021 -
Acta Neurochirurgica May 2024To assess whether diffusion tensor imaging (DTI) and generalized q-sampling imaging (GQI) metrics could preoperatively predict the clinical outcome of deep brain...
PURPOSE
To assess whether diffusion tensor imaging (DTI) and generalized q-sampling imaging (GQI) metrics could preoperatively predict the clinical outcome of deep brain stimulation (DBS) in patients with Parkinson's disease (PD).
METHODS
In this single-center retrospective study, from September 2021 to March 2023, preoperative DTI and GQI examinations of 44 patients who underwent DBS surgery, were analyzed. To evaluate motor functions, the Unified Parkinson's Disease Rating Scale (UPDRS) during on- and off-medication and Parkinson's Disease Questionnaire-39 (PDQ-39) scales were used before and three months after DBS surgery. The study population was divided into two groups according to the improvement rate of scales: ≥ 50% and < 50%. Five target regions, reported to be affected in PD, were investigated. The parameters having statistically significant difference were subjected to a receiver operating characteristic (ROC) analysis.
RESULTS
Quantitative anisotropy (qa) values from globus pallidus externus, globus pallidus internus (qa_Gpi), and substantia nigra exhibited significant distributional difference between groups in terms of the improvement rate of UPDRS-3 scale during on-medication (p = 0.003, p = 0.0003, and p = 0.0008, respectively). In ROC analysis, the best parameter in predicting DBS response included qa_Gpi with a cut-off value of 0.01370 achieved an area under the ROC curve, accuracy, sensitivity, and specificity of 0.810, 73%, 62.5%, and 85%, respectively. Optimal cut-off values of ≥ 0.01864 and ≤ 0.01162 yielded a sensitivity and specificity of 100%, respectively.
CONCLUSION
The imaging parameters acquired from GQI, particularly qa_Gpi, may have the ability to non-invasively predict the clinical outcome of DBS surgery.
Topics: Humans; Deep Brain Stimulation; Parkinson Disease; Diffusion Tensor Imaging; Female; Male; Middle Aged; Retrospective Studies; Aged; Treatment Outcome; Globus Pallidus; Predictive Value of Tests
PubMed: 38748304
DOI: 10.1007/s00701-024-06096-w