Prognostic value of regional strain by cardiovascular magnetic resonance feature tracking in hypertrophic cardiomyopathy.

BACKGROUND: Few studies have demonstrated the performance of regional strain by cardiovascular magnetic resonance (CMR) feature tracking in hypertrophic cardiomyopathy (HCM) patients, and the prognostic value of segmental strain remains unknown. This study aimed to explore the prognostic implications of strain parameters generated by CMR feature tracking analysis in HCM patients. METHODS: In total, 104 clinically diagnosed HCM patients and 30 healthy volunteers were enrolled in this study, and all patients underwent a standard CMR examination. Global and regional strain was computed by short axis, 2-, 3-, and 4-chamber view cine MR imaging using specialized software. Cardiac structure, function, and myocardial strain were compared between the control group and HCM patients, and the event and event-free groups. Univariate and multivariate Cox regression analyses were performed to evaluate the correlations between clinical and CMR parameters and poor prognosis. RESULTS: During the follow-up time, 8 patients reached the primary end points and 14 patients reached secondary end points. Regional radial strain of hypertrophic segments (RRS) and regional circumferential strain of hypertrophic segments (RCS) were worse in HCM patients with primary and secondary end points. In univariate Cox regression analysis of RRS, RCS were associated with primary and secondary end points. Regional radial strain of hypertrophic segments [hazard ratio (HR) 1.64, 95% confidence interval (CI): 1.13-2.38] and RCS (HR 2.35, 95% CI: 1.20-4.59) were independent predictors of primary end points, and RRS (HR 1.71, 95% CI: 1.09-2.66) and RCS (HR 2.63, 95% CI: 1.20-5.75) remained independent predictors of secondary end points in multivariate analysis. Kaplan-Meier survival curves indicated patients with RRS <10.0% and RCS ≥-8.5% had a higher rate of primary end points, and patients with RRS <17.9% and RCS ≥-12.1% experienced a higher rate of secondary end points. CONCLUSIONS: In HCM patients, RRS and RCS were associated with primary and secondary end points and remained independent predictors in multivariate analysis. Impaired regional strain may potentially predict poor prognosis in HCM patients. KEYWORDS: Prognosis; hypertrophic cardiomyopathy (HCM); cardiovascular magnetic resonance (CMR); regional strain.

Sequential damage assessment of the posterolateral complex of the knee joint: a finite element study.

BACKGROUND: The posterolateral complex (PLC), which consists of the popliteus tendon (PT), lateral collateral ligament (LCL), and popliteofibular ligament (PFL), is an indispensable structure of the knee joint. The aim of this study was to explore the functionality of the PLC by determining the specific role of each component in maintaining posterolateral knee stability. METHODS: A finite element (FE) model was generated based on previous material property data and magnetic resonance imaging of a volunteer's knee joint. The injury order of the PLC was set as LCL, PFL, and PT. A combined compressive load of 1150 N and an anterior tibial load of 134 N was applied to the tibia to investigate tibial displacement (TD). Tibial external rotation (TER) and tibial varus angulation (TVA) were measured under bending motions of 5 and 10 Nm. The instantaneous axis of rotation (IAR) of the knee joint under different rotation motions was also recorded. RESULTS: The TD of the intact knee under a combined compressive load of 1150 N and an anterior tibial load of 134 N matched the values determined in previous studies. Our model showed consistent increases in TD, TVA, and TER after sequential damage of the PLC. In addition, sequential disruption caused the IAR to shift superiorly and laterally during varus rotation and medially and anteriorly during external rotation. In the dynamic damage of the PLC, LCL injury had the largest effect on TD, TVA, TER, and IAR. CONCLUSIONS: Sequential injury of the PLC caused considerable loss of stability of the knee joint according to an FE model. The most significant structure of the PLC was the LCL.

Frontal White Matter Hyperintensities Effect on Default Mode Network Connectivity in Acute Mild Traumatic Brain Injury.

The functional connectivity of the brain depends not only on the structural integrity of the cortex but also on the white matter pathways between cortical areas. White matter hyperintensities (WMH), caused by chronic hypoperfusion in the white matter, play a role in the outcome of traumatic brain injury (TBI) and other neurodegenerative disorders. Herein, we investigate how the location and volume of WMH affect the default-mode network (DMN) connectivity in acute mild TBI (mTBI) patients. Forty-six patients with acute mTBI and 46 matched healthy controls were enrolled in the study. All participants underwent T2-weighted fluid-attenuated inversion recovery magnetic resonance imaging (MRI), resting-state functional MRI (fMRI),and neuropsychological assessments. The volume and location of WMH were recorded. The relationships between the WMH volume and clinical assessments were evaluated using Spearman's correlation. Patients with higher frontal lobe WMH volume had more severe post-concussion symptoms and poorer information processing speed. Moreover, these patients had significantly lower functional connectivity in the right middle temporal gyrus, left middle frontal gyrus, right superior frontal gyrus, and left anterior cingulate cortex, compared with patients with low frontal lobe WMH volume. Compared to the controls, the patients with high frontal WMH volume exhibited significantly lower functional connectivity in the right inferior temporal gyrus, left anterior cingulate cortex, and right superior frontal gyrus. These findings suggest that frontal lobe WMH volume may modulate the functional connectivity within the DMN. Therefore, the WMH volume in specific regions of the brain, particularly the frontal and parietal lobes, may accelerate the process of aging and cognitive impairment may be a useful biomarker for the diagnosis and prognosis of acute mTBI.

Sequential neural activity in sensorimotor area and mirror neural system for graded mirror therapy with imagined hand movements.

BACKGROUND: Graded motor imagery (GMI) therapy is a neural rehabilitative physiotherapy that has been shown to alleviate the severity of complex regional pain syndrome, phantom limb pain and disability. OBJECTIVE: To identify neural networks associated with the use of graded mirror therapy (MT) while imagining hand movements. METHODS: We made a block-design functional magnetic resonance imaging study of MT included three experiments: (1) immobile unimanual MT (IU-MT), in which the right hand flexed and made a fist, which then remained immobile; (2) mobilization unimanual MT (MU-MT), in which the right hand performed a flexion-extension movement; and (3) mobilization bimanual MT (MB-MT), in which both hands performed a flexion-extension movement. When subjects started their hand movements, they gazed at the mirror and imagined the same movement behind the mirror. RESULTS: We discovered that the sensorimotor area of the left brain, superior temporal gyrus/middle temporal gyrus (STG/MTG) of the right brain and visual areas were activated by IU-MT. In MU-MT, only the STG/MTG was activated. Furthermore, MB-UT mostly activated the sensorimotor area and STG of the right brain. However, there were no brain areas activated by MU-MT compared with IU-MT or MB-MT; but, MB-MT activated more motor areas than IU-MT. Importantly, we determined that the level of mirror imagery was negatively correlated with signals in the mirror neuron system (MNS) and positively related with the signals in the sensorimotor areas. CONCLUSIONS: We suggest that graded MT might be a sequential therapeutic program that can enhance the sensorimotor cortex. The MNS might have an initiating role in graded MT. Thus, there is the possibility that graded MT is a helpful treatment strategy for the rehabilitation of dysfunctional patients.

Lower Posttraumatic α-Synuclein Level Associated With Altered Default Mode Network Connectivity Following Acute Mild Traumatic Brain Injury.

This study aimed to investigate the changes of α-synuclein in serum and its relationship with default mode network (DMN) connectivity after acute mild traumatic brain injury (mild TBI). Fifty-two patients with mild TBI at the acute phase and 47 matched healthy controls were enrolled in the study. All participants received resting-state functional magnetic resonance imaging (fMRI) and neuropsychological assessments. Relations between the levels of α-synuclein in serum and clinical assessments were obtained using multivariate linear regression. Results showed that the patients with lower α-synuclein presented more complaints on post-concussion symptoms and depression. Moreover, patients with high levels of α-synuclein exhibited significantly decreased functional connectivity in the left precuneus and increased functional connectivity in both the left anterior cingulate cortex and ventro-medial prefrontal cortex (MPFC) compared with patients with low levels of α-synuclein. These findings supported that α-synuclein may modulate the functional connectivity within the DMN and suggest the feasibility of using α-synuclein as an objective biomarker for diagnosis and prognosis of mild TBI.

Preliminary Evidence of Sex Differences in Cortical Thickness Following Acute Mild Traumatic Brain Injury.

The main objective of this study was to evaluate sex differences in cortical thickness after acute mild traumatic brain injury (mTBI) and its associations with clinical outcomes. Thirty-two patients with mTBI at acute phase (2.4 ± 1.3 days post-injury) and 30 healthy controls were enrolled. All the participants underwent comprehensive neurocognitive assessments and MRI to assess cortical thickness. Significant sex differences were determined by using variance analysis of factorial design. Relations between the cortical thickness and clinical assessments were measured with the Spearman Correlation. Results revealed that patients with mTBI had significantly reduced cortical thickness in the left entorhinal cortex while increased cortical thickness in the left precuneus cortex and right lateral occipital cortex, compared with healthy controls. The interaction effect of the group × sex on cortical thickness was significant. Female patients had significant thicker cortical thickness in the left caudal anterior cingulate cortex (ACC) than male patients and had higher scores on Posttraumatic stress disorder Checklist-Civilian Version (PCL-C). Spearman correlational analysis showed a significantly positive correlations between the cortical thickness of the left caudal ACC and PCL-C ratings in female patients. Sex differences in cortical thickness support its potential as a neuroimaging phenotype for investigating the differences in clinical profiles of mild TBI between women and men.

Longitudinal Changes of Caudate-Based Resting State Functional Connectivity in Mild Traumatic Brain Injury.

Mild traumatic brain injury (mild TBI) is associated with dysfunctional brain network and accumulating evidence is pointing to the caudate as a vulnerable hub region. However, little is known about the longitudinal changes in the caudate-based resting-state functional connectivity following mild TBI. In the current study, 50 patients with mild TBI received resting-state functional magnetic resonance imaging as well as neuropsychological assessments within 7 days post-injury (acute phase) and 1 month later (subacute phase). Thirty-six age- and gender- matched healthy controls underwent the same protocol. The caudate was segmented into the dorsal and ventral sub-regions based on their related functionally distinct neural circuits and separate functional connectivity was investigated. Results indicated that patients with mild TBI at acute phase exhibited reduced left dorsal caudate-based functional connectivity with ventral lateral prefrontal cortex, dorsal anterior cingulate cortex, and inferior parietal lobule, which mainly distributed in the cognitive control network, and reduced right ventral caudate-based functional connectivity with the dorsal lateral prefrontal cortex, dorsal anterior cingulate cortex (dACC), and bilateral ventral anterior cingulate cortex (vACC), which mainly distributed in the executive network and emotional processing network. Furthermore, patients with mild TBI presented the reduced functional connectivity between the left dorsal caudate and the ventral lateral prefrontal cortex (vlPFC) compared with healthy controls at acute phase while this difference became no significance and return to the normal level following 1 month post-injury subacute phase. Similarly, the functional connectivity between the right ventral caudate and anterior cingulate cortex (both dorsal and ventral part) showed the reduced strength in patients compared with healthy controls only at the acute phase but presented no significant difference at subacute phase following mild TBI. Along the same line, patients with mild TBI presented the impaired performance on the information processing speed and more complaints on the pain impact index at acute phase compared with healthy controls but showed no significant difference at the follow-up 1 month post-injury subacute phase. The longitudinal changes of caudate-based dysfunction connectivity could serve as a neuroimaging biomarker following patients with mild TBI, with the evidence that the abnormal caudate-based functional connectivity at acute phase have returned to the normal level accompanying with the recovery of the neuropsychological syndromes following patients with mild TBI at subacute phase.

Sex Differences in Abnormal Intrinsic Functional Connectivity After Acute Mild Traumatic Brain Injury.

Mild traumatic brain injury (TBI) is considered to induce abnormal intrinsic functional connectivity within resting-state networks (RSNs). The objective of this study was to estimate the role of sex in intrinsic functional connectivity after acute mild TBI. We recruited a cohort of 54 patients (27 males and 27 females with mild TBI within 7 days post-injury) from the emergency department (ED) and 34 age-, education-matched healthy controls (HCs; 17 males and 17 females). On the clinical scales, there were no statistically significant differences between males and females in either control group or mild TBI group. To detect whether there was abnormal sex difference on functional connectivity in RSNs, we performed independent component analysis (ICA) and a dual regression approach to investigate the between-subject voxel-wise comparisons of functional connectivity within seven selected RSNs. Compared to female patients, male patients showed increased intrinsic functional connectivity in motor network, ventral stream network, executive function network, cerebellum network and decreased connectivity in visual network. Further analysis demonstrated a positive correlation between the functional connectivity in executive function network and insomnia severity index (ISI) scores in male patients (r = 0.515, P = 0.006). The abnormality of the functional connectivity of RSNs in acute mild TBI showed the possibility of brain recombination after trauma, mainly concerning male-specific.