Prediction of functional outcome in acute cerebral hemorrhage using diffusion tensor imaging at 3T: a prospective study

Diffusion Tensor Imaging 3D Tractography-Guided, Individualized, Transsulcul Approach for Subcortical Hematoma Evacuation Using BrainPath/Myriad

sICH (spontaneous intracerebral hemorrhage) is a major cause of death and disability. Traditional surgical evacuation, while beneficial, risks damaging healthy tissue. Minimally invasive surgery (MIS) offers a promising alternative. This study explores the feasibility and safety of diffusion tensor imaging (DTI)-guided, trans-sulcal MIS with BrainPath/Myriad NICO Corporation (Indianapolis, IN, USA) for sICH evacuation. DTI/tractography (DTT) visualizes critical pathways like the corticospinal tract (CST), aiding surgical planning and potentially predicting motor function recovery post-surgery. Our objectives include i) assessing the feasibility and safety of DTT-guided, trans-sulcal MIS with BrainPath/Myriad for sICH evacuation. ii) Evaluating DTT's utility in surgical planning and its potential role in predicting motor function recovery. Three sICH patients underwent pre-operative DTT with CST involvement graded A (direct injury) to E (displacement). Based on DTT, surgical trajectories using three trans-sulcal approaches were planned to avoid the CST. MIS with BrainPath/Myriad was performed aiming for <15 mL residual hematoma. Post-operative DTT and motor function follow-up (≥3 months) were conducted. Three patients completed pre- and post-operative DTT scans. All were middle-aged males with sympathomimetic abuse history. Two had Type A CST involvement, and one had Type D. Both Type A patients recovered well but showed no significant motor improvement. The Type D patient showed motor improvement. All patients completed the three-month follow-up. Our limited data suggests that DTI-guided, trans-sulcal MIS with BrainPath/Myriad for sICH evacuation is feasible and safe. DTT seems valuable for surgical planning and potentially predicts motor function recovery. Further studies with more patients are needed to confirm these findings.

Microstructure of the residual corticofugal projection from primary motor cortex in chronic stroke

Movement dysfunction after stroke is largely due to the inability of cortical motor neurons to activate spinal motor neurons via transmission of descending motor commands along the corticofugal projection from the primary motor cortex. Pathophysiological processes that ensue following injury have mostly resolved and white matter volume within the remodelled tract has mostly stabilized by the chronic stage many months to years after symptom onset. Where along the cranial course of the residual corticofugal projection white matter microstructure explains potential to activate muscles weakened by stroke at this stage is still not well understood. Here, diffusion spectrum imaging was used to reconstruct the descending corticofugal projection and quantify its microstructure in stroke survivors (n = 25) with longstanding hand impairment (7.7 ± 6.5 years). Portions of the residual tract overlapping with abnormalities on structural images were defined as the 'Overlap' compartment, and portions above and below this compartment were defined as 'Rostral' and 'Caudal' compartments, respectively. Maximal precision grip force and size of motor-evoked potentials elicited by transcranial magnetic stimulation were used to quantify activation of paretic hand muscles. Coherence of fibre anisotropy and directional diffusivities between tracts in either cerebral hemisphere was reduced in stroke survivors relative to neurologically-intact controls, with most abnormal asymmetries observed in the 'Overlap' compartment. While differences in fibre anisotropy and diffusivity between residual and intact tracts were detected most prominently in the 'Overlap' compartment, the overall magnitude of unrestricted diffusion within the 'Caudal' compartment was most closely linked to paretic muscle activation. The ability of cortical motor neurons to access spinal motor neuron pools long after stroke onset is therefore associated with microstructural integrity in portions of the residual corticofugal projection subject to secondary degeneration. These findings expand knowledge on white matter adaptation in response to neurological injury and may inform applications that seek to reverse brain pathology long after stroke onset when movement dysfunction tends to persist.

Involvement of the posterior limb of the internal capsule independently predicts the prognosis of patients with basal ganglia and thalamic hemorrhage

Background

Intracerebral hemorrhage (ICH) is the most lethal and devastating subtype of stroke. Basal ganglia hemorrhage and thalamic hemorrhage are the most common types of ICH, accounting for 50-70% of all ICH cases, leading to disability and death, and it involves the posterior limb of the internal capsule to varying degrees. In this study, we investigated the impact of varying degrees of the involvement of the posterior limb of the internal capsule on the prognosis of patients with basal ganglia and thalamic ICH and assessed whether it improves the predictive accuracy of the max-ICH score, an existing scale for ICH functional outcome.

Methods

This is a multicenter, retrospective, observational study. We graded the involvement of the posterior limb of the internal capsule according to the degree of compression and injury (called iICH, ranging from 0 to 4). An unfavorable outcome was defined as a 90-day modified Rankin Scale (mRS) of > 2. Multivariate logistic regression analysis was used to identify independent risk factors associated with unfavorable prognosis. The discrimination was verified using receiver operating characteristic curve (ROC) analysis, while the calibration was verified by the Hosmer-Lemeshow test.

Results

Of the 305 patients included, 188 from Nanfang Hospital were assigned to the development cohort, and 117 from Heyuan People's Hospital and Huadu District People's Hospital were assigned to the validation cohort. In the development cohort, iICH was identified as an independent factor of a 90-day unfavorable outcome, and the area under the ROC (AUC) was 0.774. When combined with the iICH, the AUC of max-ICH was significantly elevated from 0.816 to 0.866. Comparable results were found in the validation cohort.

Conclusions

Increased involvement of the posterior limb of the internal capsule is associated with a worse outcome in patients with basal ganglia and thalamic ICH.

Buyang huanwu decoction promotes remyelination via miR-760-3p/GPR17 axis after intracerebral hemorrhage

ETHNOPHARMACOLOGICAL RELEVANCE

The repairment of myelin sheaths is crucial for mitigating neurological impairments of intracerebral hemorrhage (ICH). However, the current research on remyelination processes in ICH remains limited. A representative traditional Chinese medicine, Buyang Huanwu decoction (BYHWD), shows a promising therapeutic strategy for ICH treatment.

AIM OF THE STUDY

To investigate the pro-remyelination effects of BYHWD on ICH and explore the underlying mechanisms.

MATERIALS AND METHODS

The collagenase-induced mice ICH model was created for investigation. BYHWD's protective effects were assessed by behavioral tests and histological staining. Transmission electron microscopy was used for displaying the structure of myelin sheaths. The remyelination and oligodendrocyte differentiation were evaluated by the expressions of myelin proteolipid protein (PLP), myelin basic protein (MBP), MBP/TAU, Olig2/CC1, and PDGFRα/proliferating cell nuclear antigen (PCNA) through RT-qPCR and immunofluorescence. Transcriptomics integrated with disease database analysis and experiments in vivo and in vitro revealed the microRNA-related underlying mechanisms.

RESULTS

Here, we reported that BYHWD promoted the neurological function of ICH mice and improved remyelination by increasing PLP, MBP, and TAU, as well as restoring myelin structure. Besides, we showed that BYHWD promoted remyelination by boosting the differentiation of PDGFRα+ oligodendrocyte precursor cells into olig2+/CC1+ oligodendrocytes. Additionally, we demonstrated that the remyelination effects of BYHWD worked by inhibiting G protein-coupled receptor 17 (GPR17). miRNA sequencing integrated with miRNA database prediction screened potential miRNAs targeting GPR17. By applying immunofluorescence, RNA in situ hybridization and dual luciferase reporter gene assay, we confirmed that BYHWD suppressed GPR17 and improved remyelination by increasing miR-760-3p.

CONCLUSIONS

BYHWD improves remyelination and neurological function in ICH mice by targeting miR-760-3p to inhibit GPR17. This study may shed light on the orchestration of remyelination mechanisms after ICH, thus providing novel insights for developing innovative prescriptions with brain-protective properties.

SLC45A3 Serves as a Potential Therapeutic Biomarker to Attenuate White Matter Injury After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a severe cerebrovascular disease, which impairs patients' white matter even after timely clinical interventions. Indicated by studies in the past decade, ICH-induced white matter injury (WMI) is closely related to neurological deficits; however, its underlying mechanism and pertinent treatment are yet insufficient. We gathered two datasets (GSE24265 and GSE125512), and by taking an intersection among interesting genes identified by weighted gene co-expression networks analysis, we determined target genes after differentially expressing genes in two datasets. Additional single-cell RNA-seq analysis (GSE167593) helped locate the gene in cell types. Furthermore, we established ICH mice models induced by autologous blood or collagenase. Basic medical experiments and diffusion tensor imaging were applied to verify the function of target genes in WMI after ICH. Through intersection and enrichment analysis, gene SLC45A3 was identified as the target one, which plays a key role in the regulation of oligodendrocyte differentiation involving in fatty acid metabolic process, etc. after ICH, and single-cell RNA-seq analysis also shows that it mainly locates in oligodendrocytes. Further experiments verified overexpression of SLC45A3 ameliorated brain injury after ICH. Therefore, SLC45A3 might serve as a candidate therapeutic biomarker for ICH-induced WMI, and overexpression of it may be a potential approach for injury attenuation.

Stroke-Induced Secondary Neurodegeneration of the Corticospinal Tract-Time Course and Mechanisms Underlying Signal Changes in Conventional and Advanced Magnetic Resonance Imaging

Secondary neurodegeneration refers to the final result of several simultaneous and sequential mechanisms leading to the loss of substance and function in brain regions connected to the site of a primary injury. Stroke is one of the most frequent primary injuries. Among the subtypes of post-stroke secondary neurodegeneration, axonal degeneration of the corticospinal tract, also known as Wallerian degeneration, is the most known, and it directly impacts motor functions, which is crucial for the motor outcome. The timing of its appearance in imaging studies is usually considered late (over 4 weeks), but some diffusion-based magnetic resonance imaging (MRI) techniques, as diffusion tensor imaging (DTI), might show alterations as early as within 7 days from the stroke. The different sequential pathological stages of secondary neurodegeneration provide an interpretation of the signal changes seen by MRI in accordance with the underlying mechanisms of axonal necrosis and repair. Depending on the employed MRI technique and on the timing of imaging, different rates and thresholds of Wallerian degeneration have been provided in the literature. In fact, three main pathological stages of Wallerian degeneration are recognizable-acute, subacute and chronic-and MRI might show different changes: respectively, hyperintensity on T2-weighted sequences with corresponding diffusion restriction (14-20 days after the injury), followed by transient hypointensity of the tract on T2-weighted sequences, and by hyperintensity and atrophy of the tract on T2-weighted sequences. This is the main reason why this review is focused on MRI signal changes underlying Wallerian degeneration. The identification of secondary neurodegeneration, and in particular Wallerian degeneration, has been proposed as a prognostic indicator for motor outcome after stroke. In this review, the main mechanisms and neuroimaging features of Wallerian degeneration in adults are addressed, focusing on the time and mechanisms of tissue damage underlying the signal changes in MRI.

Applicability of fractional anisotropy from standardized automated tractography for outcome prediction of patients after stroke

[Purpose] Diffusion-tensor fractional anisotropy has been used for outcome prediction in stroke patients. We assessed the clinical applicability of the two major fractional anisotropy methodologies-fractional anisotropy derived from segmentation maps in the standard brain (region of interest) and fractional anisotropy derived from standardized automated tractography-in relation to outcomes. [Participants and Methods] The study design was a retrospective survey of medical records collected from October 2021 to September 2022. Diffusion-tensor imaging was conducted in the second week after stroke onset. Outcomes were assessed using the total score of the motor component of the Stroke Impairment Assessment Set (null to full, 0 to 25). Correlations between fractional anisotropy and the outcomes were then assessed. [Results] Fourteen patients with hemorrhagic stroke were sampled. The fractional anisotropy from standardized automated tractography of the corticospinal tract on the lesion side (mean ± standard deviation, 0.403 ± 0.070) was significantly and tightly correlated (r=0.813) with the outcomes (13.4 ± 9.2), whereas the fractional anisotropy from a region of interest set in the cerebral peduncle on the lesion side (0.548 ± 0.064) was not significantly correlated with the outcomes (r=0.507). [Conclusion] The findings suggest that fractional anisotropy derived from standardized automated tractography can be more applicable to outcome prediction than that derived from a region of interest defined in the standard brain.

Association between superior longitudinal fasciculus, motor recovery, and motor outcome after stroke: a cohort study

Introduction

Parieto-frontal interactions are mediated by the superior longitudinal fasciculus (SLF) and are crucial to integrate visuomotor information and mediate fine motor control. In this study, we aimed to characterize the relation of white matter integrity of both parts of the SLF (SLF I and SLF II) to both motor outcome and recovery and its evolution over time in stroke patients with upper limb motor deficits.

Materials and methods

Fractional anisotropy (FA) values over the SLF I, SLF II, and corticospinal tract (CST) and upper limb motor performance evaluated by both the upper limb Fugl-Meyer Assessment score and maximum grip strength were measured for 16 patients at 3 weeks, 6 weeks, and 12 weeks poststroke. FA changes were assessed over time using repeated-measures Friedman ANOVA, and correlations between motor recovery, motor outcome at 12 weeks, and FA values in the CST, SLF I, and SLF II at 3 weeks were performed using Spearman's rank-order correlation.

Results

FA values in the affected hemisphere's SLF I and SLF II at 3 weeks correlated with motor recovery at 12 weeks when assessed by the Fugl-Meyer Assessment for upper limb extremity (rho: 0.502, p: 0.04 and rho: 0.510, p: 0.04, respectively) but not when assessed by grip strength. FA values in the SLF I and SLF II were not correlated with motor outcomes. FA values in the SLF II in the affected hemisphere changed significantly over time (p: 0.016).

Conclusion

Both SLF I and SLF II appeared to participate in poststroke motor recovery of complex movements but not in the motor outcome. These results argue that visually/spatially oriented motor tasks as well as more complex motor tasks using parietal associative areas should be used for poststroke rehabilitation strategies.

Correlation between spasticity and corticospinal/corticoreticular tract status in stroke patients after early stage

We investigated the correlation between spasticity and the states of the corticospinal tract (CST) and corticoreticular tract (CRT) in stroke patients after early stage. Thirty-eight stroke patients and 26 healthy control subjects were recruited. The modified Ashworth scale (MAS) scale after the early stage (more than 1 month after onset) was used to determine the spasticity state of the stroke patients. Fractional anisotropy (FA), apparent diffusion coefficient (ADC), fiber number (FN), and ipsilesional/contra-lesional ratios for diffusion tensor tractography (DTT) parameters of the CST and CRT after the early stage were measured in both ipsi- and contra-lesional hemispheres. This study was conducted retrospectively. The FA and FN CST-ratios in the patient group were significantly lower than those of the control group (P < .05), except for the ADC CST-ratio (P > .05). Regarding the DTT parameters of the CRT-ratio, the patient group FN value was significantly lower than that of the control group (P < .05), whereas the FA and ADC CRT-ratios did not show significant differences between the patient and control groups (P > .05). MAS scores showed a strong positive correlation with the ADC CRT-ratio (P < .05) and a moderate negative correlation with the FN CRT-ratio (P < .05). We observed that the injury severities of the CST and CRT were related to spasticity severity in chronic stroke patients; moreover, compared to the CST, CRT status was more closely related to spasticity severity.

Acute corticospinal tract diffusion tensor imaging predicts 6-month functional outcome after intracerebral haemorrhage

INTRODUCTION

Diffusion tensor imaging (DTI) can assess the structural integrity of the corticospinal tract (CST) in vivo. We aimed to investigate whether CST DTI metrics after intracerebral haemorrhage (ICH) are associated with 6-month functional outcome and can improve the predictive performance of the existing ICH score.

METHODS

We retrospectively included 42 patients with DTI performed within 5 days after deep supratentorial spontaneous ICH. Ipsilesional-to-contralesional ratios were calculated for fractional anisotropy (rFA) and mean diffusivity (rMD) in the pontine segment (PS) of the CST. We determined the most predictive variables for poor 6-month functional outcome [modified Rankin Scale (mRS) > 2] using the least absolute shrinkage and selection operator (LASSO) method. We calculated discrimination using optimism-adjusted estimation of the area under the curve (AUC).

RESULTS

Patients with 6-month mRS > 2 had lower rFA (0.945 [± 0.139] vs 1.045 [± 0.130]; OR 0.004 [95% CI 0.00-0.77]; p =  0.04) and higher rMD (1.233 [± 0.418] vs 0.963 [± 0.211]; OR 22.5 [95% CI 1.46-519.68]; p = 0.02). Discrimination (AUC) values were: 0.76 (95% CI 0.61-0.91) for the ICH score, 0.71 (95% CI 0.54-0.89) for rFA, and 0.72 (95% CI 0.61-0.91) for rMD. Combined models with DTI and non-DTI variables offer an improvement in discrimination: for the best model, the AUC was 0.82 ([95% CI 0.68-0.95]; p = 0.15).

CONCLUSION

In our exploratory study, PS-CST rFA and rMD had comparable predictive ability to the ICH score for 6-month functional outcome. Adding DTI metrics to clinical-radiological scores might improve discrimination, but this needs to be investigated in larger studies.

Validation of Presurgical Simulation of White Matter Damage Using Diffusion Tensor Imaging

BACKGROUND

The understanding of white matter (WM) was revolutionized by the emergence of tractography based on diffusion tensor imaging (DTI). Currently, DTI simulations are implemented in preoperative planning to optimize surgical approaches. The reliability of these simulations has been questioned and investigated seeking for correlation between neurological performance and anomalies in DTI parameters. However, the ability of preoperative WM simulations to predict a surgical injury has not been thoroughly evaluated. Our objective was to assess the reliability of preoperatively simulated WM injuries for conventional neurosurgical procedures.

METHODS

WM surgical damage was preoperatively simulated by creating a 3-dimensional volume representing the endoscope or the surgical trajectory. This volume was used as an additional region of interest in the fascicle reconstruction to be subtracted from the original fascicle. Simulated, injured fascicles were compared in terms of the number of fibers and volume to those created from postoperative DTI studies. Reliability was assimilated into the correlation between the simulation and the postoperative reconstruction; evaluated using the intraclass correlation coefficient or Lin's Concordance correlation coefficient (CCC), and represented on Bland-Altman plots.

RESULTS

The preoperative and postoperative DTI studies of 30 patients undergoing various neurosurgical approaches were processed. The correlation between simulated injuries and postoperative studies was high in terms of fibers (Concordance correlation coefficient = Rho.C = 0.989 [95% confidence interval = 0.979-0.995]) and volume (intraclass correlation coefficient = 0.95 [95% CI = 0.89-0.97]). Bland-Altman plots demonstrated that the great majority of cases fell within the mean ± 2 Standard deviations.

CONCLUSIONS

Presurgical simulation of WM fascicles based on DTI is consistent with postoperative DTI studies. These findings require further validation by neurophysiological and clinical correlation.

Monophasic-Quadripulse Theta Burst Magnetic Stimulation for Motor Palsy Functional Evaluation After Intracerebral Hemorrhage

Transcranial magnetic stimulation (TMS) is commonly employed for diagnostic and therapeutic purposes to enhance recovery following brain injury, such as stroke or intracerebral hemorrhage (ICH). Single-pulse TMS, most commonly used for diagnostic purposes and with motor evoked potential (MEP) recordings, is not suitable for clinical use in patients with severe motor paresis. To overcome this problem, we developed a quadripulse theta burst transcranial magnetic stimulation (QTS) device that combines the output from 16 stimulators to deliver a train of 16 monophasic magnetic pulses through a single coil. High-frequency theta rhythm magnetic bursts (bursts of four monophasic pulses, at 500 Hz, i.e., with a 2-ms interpulse interval, repeated at 5 Hz) were generated via a set of 16 separate magnetic stimulators connected to a specially designed combination module. No adverse effects or electroencephalogram (EEGs) abnormalities were identified during or after the recordings. MEP amplification in the QTS during four-burst theta rhythm stimulations produced four independent MEPs 20 ms after each burst onset maximizing the final third or fourth burst, which exhibited significantly greater amplitude than those resulting from a single burst or pulse. Motor functional palsy grades after ICH and QTS-MEP parameters and resting motor threshold (RMT) and amplitudes were significantly correlated (r = −0.83/−0.81 and 0.89/0.87; R2 = 0.69/0.66 and 0.79/0.76, p &lt; 0.001; anterior/posterior-stimulus polarity, respectively). In conclusion, QTS-MEPs enabled a linear functional evaluation in patients with various degrees of motor paresis. However, the benefits, safety, and limitations of this device should be further explored in future studies.

Utility of transcranial magnetic stimulation and diffusion tensor imaging for prediction of upper-limb motor recovery in acute ischemic stroke patients

Background:

The recovery of the upper-limb (UL) motor function after ischemic stroke (IS) remains a major scientific, clinical, and patient concern and it is hard to predict alone from the clinical symptoms.

Objective:

To determine the accuracy of the prediction of the recovery of UL motor function in patients with acute ischemic middle cerebral artery (MCA) stroke using individual clinical, transcranial magnetic stimulation (TMS) or diffusion tensor imaging (DTI) parameters or their combination.

Methods and Material:

The first-ever acute ischemic MCA stroke patients within 7 days of the stroke onset who had an obvious UL motor deficit underwent TMS for the presence of motor-evoked potential (MEP) and DTI to evaluate the integrity of corticospinal tracts. Multivariate logistic regression analysis was done to test for the accuracy of the prediction of the recovery of UL motor function.

Results:

Twenty-nine acute ischemic MCA stroke patients (21 males and 8 females) with a mean age of 51.45 ± 14.26 years were recruited. Model-I included clinical scales (Fugl-Meyer Assessment [FMA] + Motricity Index [MI]) + TMS (MEP) + DTI (fractional anisotropy [FA]) were found to be the most accurate predictive model, with the overall predictive ability (93.3%; 95% confidence interval [CI]: 0.87–0.99) and sensitivity: 94.9% (95% CI: 0.87–1.0) and specificity: 95.8% (95% CI: 0.89–1.0); respectively.

Conclusion:

The accuracy of UL motor recovery can be predicted through the clinical battery and their elements as well as TMS (MEP) and DTI (FA) parameters. Further, well-designed prospective studies are needed to confirm our findings.

White Matter Survival within and around the Hematoma: Quantification by MRI in Patients with Intracerebral Hemorrhage

White matter (WM) injury and survival after intracerebral hemorrhage (ICH) has received insufficient attention. WM disruption surrounding the hematoma has been documented in animal models with histology, but rarely in human ICH with noninvasive means, like magnetic resonance imaging (MRI). A few human MRI studies have investigated changes in long WM tracts after ICH remote from the hematoma, like the corticospinal tract, but have not attempted to obtain an unbiased quantification of WM changes within and around the hematoma over time. This study attempts such quantification from 3 to 30 days post ictus. Thirteen patients with mild to moderate ICH underwent diffusion tensor imaging (DTI) MRI at 3, 14, and 30 days. Fractional anisotropy (FA) maps were used to calculate the volume of tissue with FA > 0.5, both within the hematoma (lesion) and in the perilesional tissue. At day 3, the percentages of both lesional and perilesional tissue with an FA > 0.5 were significantly less than contralateral, unaffected, anatomically identical tissue. This perilesional contralateral difference persisted at day 14, but there was no significant difference at day 30. The loss of perilesional tissue with FA > 0.5 increased with increasing hematoma size at day 3 and day 14. All patients had some tissue within the lesion with FA > 0.5 at all time points. This did not decrease with duration after ictus, suggesting the persistence of white matter within the hematoma/lesion. These results outline an approach to quantify WM injury, both within and surrounding the hematoma, after mild to moderate ICH using DTI MRI. This may be important for monitoring treatment strategies, such as hematoma evacuation, and assessing efficacy noninvasively.

Relationship Between Motor Function, DTI, and Neurophysiological Parameters in Patients with Stroke in the Recovery Rehabilitation unit

OBJECTIVES

We investigated the relationship between pyramidal tract evaluation indexes (i.e., diffusion tensor imaging, transcranial magnetic stimulation (TMS)-induced motor-evoked potential (MEP), and central motor conduction time (CMCT) on admission to the recovery rehabilitation unit) and motor functions at discharge in patients with ischemic or hemorrhagic stroke.

MATERIALS AND METHODS

Seventeen patients were recruited (12 men; 57.9 ± 10.3 years). The mean fractional anisotropy (FA) values of the right and left posterior limbs of the internal capsule were estimated using a computer-automated method. We determined the ratios of FA values in the affected and unaffected hemispheres (rFA), TMS-induced MEP, and the ratios of CMCT in the affected and unaffected hemispheres (rCMCT) and examined their association with motor functions (Fugl-Meyer Assessment (FMA) and Action Research Arm Test (ARAT)) at discharge.

RESULTS

Higher rFA values of the posterior limb of the internal capsule on admission to the recovery rehabilitation unit led to a better recovery of upper limb function (FMA: r = 0.78, p < 0.001; ARAT: r = 0.74, p = 0.001). Patients without MEP had poorer recovery of upper limb function than those with MEP (FMA: p < 0.001; ARAT: p = 0.001). The higher the rCMCT, the poorer the recovery of upper limb function (ARAT: r = -0.93, p < 0.001). However, no association was observed between the pyramidal tract evaluation indexes and recovery of lower limb motor function.

CONCLUSIONS

Evaluating the pyramidal tract is useful for predicting upper limb function prognosis, but not for lower limb function prognosis.

Mechanism of White Matter Injury and Promising Therapeutic Strategies of MSCs After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is the most fatal subtype of stroke with high disability and high mortality rates, and there is no effective treatment. The predilection site of ICH is in the area of the basal ganglia and internal capsule (IC), where exist abundant white matter (WM) fiber tracts, such as the corticospinal tract (CST) in the IC. Proximal or distal white matter injury (WMI) caused by intracerebral parenchymal hemorrhage is closely associated with poor prognosis after ICH, especially motor and sensory dysfunction. The pathophysiological mechanisms involved in WMI are quite complex and still far from clear. In recent years, the neuroprotection and repairment capacity of mesenchymal stem cells (MSCs) has been widely investigated after ICH. MSCs exert many unique biological effects, including self-recovery by producing growth factors and cytokines, regenerative repair, immunomodulation, and neuroprotection against oxidative stress, providing a promising cellular therapeutic approach for the treatment of WMI. Taken together, our goal is to discuss the characteristics of WMI following ICH, including the mechanism and potential promising therapeutic targets of MSCs, aiming at providing new clues for future therapeutic strategies.

Acute changes in diffusion tensor-derived metrics and its correlation with the motor outcome in gliomas adjacent to the corticospinal tract

Background:

This study involves analysis of the relationship between variables obtained using diffusion tensor imaging (DTI) and motor outcome in gliomas adjacent to the corticospinal tract (CST).

Methods:

Histologically confirmed glioma patients who were to undergo surgery between January 2018 and December 2019 were prospectively enrolled. All patients had a preoperative magnetic resonance imaging (MRI) study that included DTI, a tumor 2 cm or less from the CST, and postsurgical control within 48 h. Patients with MRI that was performed at other center, tumors with primary and premotor cortex invasion, postsurgical complications directly affecting motor outcome and tumor progression <6 months were excluded in the study. In pre- and post-surgical MRI, we measured the following DTI-derived metrics: fractional anisotropy (FA), mean diffusivity, axial diffusivity, and radial diffusivity of the entire CST and peritumoral CST regions and in the contralateral hemisphere. The motor outcome was assessed at 1, 3, and 6 months using the Medical Research Council scale.

Results:

Eleven patients were analyzed, and six corresponded to high-grade gliomas and five to low-grade gliomas. Four patients had previous motor impairment and seven patients had postsurgical motor deficits (four transient and three permanent). An FA ratio of 0.8 between peritumoral CST regions and the contralateral hemisphere was found to be the cutoff, and lower values were obtained in patients with permanent motor deficits.

Conclusion:

Quantitative analysis of DTI that was performed in the immediate postsurgery period can provide valuable information about the motor prognosis after surgery for gliomas near the CST.

Functional Outcome After Minimally Invasive Endoscopic Evacuation of Thalamic Intracerebral Hemorrhage

BACKGROUND

Intracerebral hemorrhage (ICH) is the most devastating form of stroke, with thalamic hemorrhages carrying the worst outcomes. Minimally invasive (MIS) endoscopic ICH evacuation is a promising new therapy for the condition. However, it remains unclear whether therapy success is location dependent. Here we present long-term functional outcomes after MIS evacuation of spontaneous thalamic hemorrhages.

METHODS

Patients presenting to a single urban health system with spontaneous ICH were triaged to a central hospital for management of ICH. Operative criteria for MIS evacuation included hemorrhage volume ≥15 mL, age ≥18, National Institutes of Health Stroke Scale ≥6, and baseline modified Rankin Score (mRS) ≤3. Demographic, radiographic, and clinical data were collected prospectively, and descriptive statistics were performed retrospectively. Functional outcomes were assessed using 6-month mRS scores.

RESULTS

Endoscopic ICH evacuation was performed on 21 patients. Eleven patients had hemorrhage confined to the thalamus, whereas 10 patients had hemorrhages in the thalamus and surrounding structures. Eighteen patients (85.7%) had intraventricular extension. The average preoperative volume was 39.8 mL (standard deviation [SD]: 31.5 mL) and postoperative volume was 3.8 mL (SD: 6.1 mL), resulting in an average evacuation rate of 91.4% (SD: 11.1%). One month after hemorrhage, 2 patients (9.5%) had expired and all other patients remained functionally dependent (90.5%). At 6-month follow-up, 4 patients (19.0%) had improved to a favorable outcome (mRS ≤ 3).

CONCLUSION

Among patients with ICH undergoing medical management, those with thalamic hemorrhages have especially poor outcomes. This study suggests that MIS evacuation can be safely performed in a thalamic population. It also presents long-term functional outcomes that can aid in planning randomization schemes or subgroup analyses in future MIS evacuation clinical trials.

Peri-hematoma corticospinal tract integrity in intracerebral hemorrhage patients: A diffusion-tensor imaging study

BACKGROUND

The impact of perihematoma edema in Intracerebral Hemorrhage (ICH) on white matter integrity is uncertain. Fractional Anisotropy (FA), as measured with Diffusion Tensor Imaging (DTI), can be used to assess white matter microstructure. We tested the hypotheses that sections of the Corticospinal Tract (CST) passing through perihematoma edema would 1) have low FA relative to the contralateral CST and 2) would predict NIHSS motor score in ICH patients.

METHODS

Patients were prospectively imaged with DTI at 48 h and 7 days after onset. Edema volume/extent was measured on CT at baseline and 24 h. FA, mean, axial and radial diffusivity were measured in the perihematoma edema, contralateral CST and sections of CST passing through the edema ('edematous CST').

RESULTS

Patients (n = 27, mean age 67 ± 13) were scanned with DTI at a median (IQR) of 42.3 (24.5) hours and 7.7 (1.8) days from onset. Median acute ICH volume was 8.8 (22) ml. FA in edematous CST at 72 h was decreased (0.37 ± 0.03) relative to contralateral CST (0.52 ± 0.06; p < 0.0001). Day 7 FA in edematous CST (0.35 ± 0.08) was also decreased compared to contralateral CST (0.54 ± 0.06; p < 0.0001). FA remained stable between 72 h (0.37 ± 0.03) and day 7 (0.35 ± 0.07; p = 0.350). FA at 72 h (ρ = -0.22, p = 0.420) and day 7 (ρ = -0.14, p = 0.624) was unrelated to 90-day motor score.

CONCLUSIONS

FA is decreased in the CST where it passes through the edema. Decreased FA in the edematous CST remained stable over time, was unrelated to motor score, and may represent water infiltration into the tracts rather than axonal injury.

Evidence of motor injury due to damaged corticospinal tract following acute hemorrhage in the basal ganglia region

The integrity of the corticospinal tract (CST) is significantly affected following basal ganglia haemorrhage. We aimed to assess the local features of CST and to effectively predict motor function by diffusion characteristics of CST in patients with motor injury following acute haemorrhage in the acute basal ganglia region. We recruited 37 patients with paresis of the lateral limbs caused by acute basal ganglia haemorrhage. Based on the automated fiber quantification method to track CST, assessed the character of each CST segment between the affected and contralateral sides, and correlated these with the Fugl-Meyer (FM) and Barthel Index (BI) scores at 6 months after onset. The fractional anisotropy (FA) values of the injured side of CST showed a significantly lower FA than the contralateral side along the tract profiles (p < 0.05, corrections for multiple comparisons). The FA values of each site at the internal capsule, closed corona radiata were positively correlated with the FM and BI score at 6 months after onset (p < 0.001, respectively). Our findings assessed the character of CST vividly in detail and dementated the primary sites of CST can predict the long-term outcome of motor function. This study may facilitate future clinical and cognitive studies of acute haemorrhage.

Quantitative Corticospinal Tract Assessment in Acute Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) prognostication during the acute phase is often subjective among physicians and often affects treatment decisions. The present study explores objective imaging parameters using quantitative corticospinal tract (CST) fiber reconstruction during the acute phase of ICH and correlates these parameters with functional outcome and patient recovery. We prospectively enrolled nonsurgical spontaneous supratentorial ICH patients and obtained an MRI scan on day 5 ± 1. Q-space diffeomorphic reconstruction was performed using DSI Studio, and quantitative anisotropy (QA) was calculated. The CST was reconstructed based on QA. The dichotomized modified Rankin Scale score on day 90 (favorable outcome = 0–2) and Barthel Index (favorable recovery = 100 on day 90 or improvement between discharge and day 90 > 60%) were assessed. Thirty-three patients, median age 72 years (interquartile range (IQR) 64–83), 21 female (64%), 21 (64%) with lobar hemorrhage, median ICH volume on admission 15.0 (IQR 7.0–27.4) mL, were included. Sixteen patients (48%) had a favorable outcome and 24 (73%) had a favorable recovery. The mean number of ipsilesional reconstructed CST fiber pathways was higher in patients with favorable outcomes (153 (standard deviation (SD) 103) vs. 60 (SD 39), p = 0.003) and predicted outcome after adjustment (Exp(B) = 1.016 (95% CI = 1.002–1.030)). QA in the ipsilesional posterior limb of the internal capsule showed a trend towards an association with favorable outcome (Exp(B) = 1.194 (95% CI = 0.991–1.439 (adjusted))). The total (ipsilesional + contralesional) number of reconstructed fiber pathways was associated with favorable recovery (Exp(B) = 1.025 (95% CI = 1.003–1.047 (adjusted))). Quantitative tractography parameters assessed in the acute phase of ICH may represent a promising predictor of long-term outcome and recovery. This might facilitate prognostic evaluation and organization of rehabilitation.

Changes in the Corticospinal Tract Beyond the Ischemic Lesion Following Acute Hemispheric Stroke: A Diffusion Kurtosis Imaging Study

BACKGROUND

The degeneration of the corticospinal tract (CST) in chronic stroke has been widely described using diffusion tensor imaging and correlates with the extent of motor deficits. However, only a few studies have reported the early degeneration in the distal CST during the acute stage of stroke and pathological changes in the distal CST have not been described.

PURPOSE

To study the microstructural changes along the CST beyond the ischemic lesion in acute stroke using diffusion kurtosis imaging (DKI).

STUDY TYPE

Prospective.

POPULATION

In all, 48 patients (26 males, 22 females; mean age 58.27 ± 12.89 years) with acute ischemic stroke.

SEQUENCE

A DKI sequence with three b-values (0, 1000, and 2000 s/mm2 ) at 3.0T MRI.

ASSESSMENT

The kurtosis and tensor parameters were derived from DKI and were compared along the length of the CST beyond the ischemic lesion between the affected and unaffected hemispheres using both voxelwise and slicewise analysis. The degree of neurological deficits was evaluated using the National Institute of Health Stroke Score (NIHSS) and the Barthel index and the clinical outcome at 3 months was evaluated using a modified Rankin scale.

STATISTICAL TESTS

Paired t-tests, a linear mixed model, and multivariate linear regression.

RESULTS

Voxelwise analysis demonstrated increased mean kurtosis, increased axial kurtosis, and decreased axial diffusivity in the affected CST, which were seen only at the level of the cerebral peduncle (all corrected P < 0.05). Slicewise analysis also demonstrated increased axial kurtosis in the cerebral peduncle of the affected CST (corrected P < 0.05). The axial kurtosis from slicewise analysis independently correlated with the motor component of NIHSS (β = 0.297, P = 0.040).

DATA CONCLUSION

Our findings suggest that early anterograde degeneration occurs along the axon direction in the distal CST in acute stroke, and can be detected using DKI. Moreover, acute axonal degeneration along the CST correlated with motor deficits.

LEVEL OF EVIDENCE

2 TECHNICAL EFFICACY STAGE: 1 J. Magn. Reson. Imaging 2020;52:512-519.

Lower total protein and absence of neuronavigation are novel poor prognostic factors of endoscopic hematoma removal for intracerebral hemorrhage

OBJECTIVES

Endoscopic hematoma removal is widely performed for the treatment of intracerebral hemorrhage. We investigated the factors related to the prognosis of intracerebral hemorrhage after endoscopic hematoma removal.

MATERIALS AND METHODS

From 2013 to 2019, we retrospectively analyzed 75 consecutive patients with hypertensive intracerebral hemorrhage who underwent endoscopic hematoma removal. Their characteristics, including neurological symptoms, laboratory data, and radiological findings were investigated using univariate and multivariate analysis. Complications during hospitalization, Glasgow Coma Scale (GCS) score on day 7, and modified Rankin Scale (mRS) score at 6 months were considered as treatment outcomes.

RESULTS

The mean age of the patients (33 women, 42 men) was 71.8 (36-95) years. Mean GCS scores at admission and on day 7 were 10.3 ± 3.2 and 11.7 ± 3.8, respectively. The mean mRS score at 6 months was 3.8 ± 1.6, and poor outcome (mRS score ranging from 3 to 6 at 6 months) in 53 patients. Rebleeding occurred in 4 patients, and other complications in 15 patients. Multivariate analysis revealed that older age, hematoma in the basal ganglia, lower total protein level, higher glucose level, and absence of neuronavigation were associated with poor outcomes. Of the 75 patients, 9 had cerebellar hemorrhages, and they had relatively favorable outcomes compared to those with supratentorial hemorrhages.

CONCLUSION

Several factors were related to the prognosis of intracerebral hemorrhage after endoscopic hematoma removal. Lower total protein level at admission and absence of neuronavigation were novel factors related to poor outcomes of endoscopic hematoma removal for intracerebral hemorrhage.

Protracted Morphological Changes in the Corticospinal Tract Within the Cervical Spinal Cord After Intracerebral Hemorrhage in the Right Striatum of Mice

Intracerebral hemorrhage (ICH) is associated with high morbidity and mortality rates. Currently, there is no promising treatment that improves prognosis significantly. While a thorough investigation of the pathological process within the primary site of injury in the brain has been conducted by the research field, the focus was mainly on gray matter injury, which partly accounted for the failure of discovery of clinically efficacious treatments. It is not until recent years that white matter (WM) injury in the brain after subcortical ICH was examined. As WM tracts form networks between different regions, damage to fibers should impair brain connectivity, resulting in functional impairment. Although WM changes have been demonstrated in the brain after ICH, alterations distant from the initial injury site down in the spinal cord are unclear. This longitudinal study, for the first time, revealed prolonged morphological changes of the contralesional dorsal corticospinal tract (CST) in the spinal cord 5 weeks after experimental ICH in mice by confocal microscopy and transmission electron microscopy, implying that the structural integrity of the CST was compromised extensively after ICH. Given the important role of CST in motor function, future translational studies targeting motor recovery should delineate the treatment effects on CST integrity.

Prediction of Motor Recovery in Patients with Basal Ganglia Hemorrhage Using Diffusion Tensor Imaging

Predicting prognosis in patients with basal ganglia hemorrhage is difficult. This study aimed to investigate the usefulness of diffusion tensor imaging in predicting motor outcome after basal ganglia hemorrhage. A total of 12 patients with putaminal hemorrhage were included in the study (aged 50 ± 12 years), 8 patients were male (aged 46 ± 11 years) and 4 were female (aged 59 ± 9 years). We performed diffusion tensor imaging and measured clinical outcome at baseline (pre) and 3 weeks (post1), 3 months (post2), and 6 months (post3) after the initial treatment. In the affected side of the brain, the mean fractional anisotropy (FA) value on pons was significantly higher in the good outcome group than that in the poor outcome group at pre (p = 0.004) and post3 (p = 0.025). Pearson correlation analysis showed that mean FA value at pre significantly correlated with the sum of the Brunnstrom motor recovery stage scores at post3 (R = 0.8, p = 0.002). Change in the FA ratio on diffusion tractography can predict motor recovery after hemorrhagic stroke.

Magnetic resonance imaging markers reflect cognitive outcome after rehabilitation in children with acquired brain injury

PURPOSE

To test markers from conventional and diffusion Magnetic Resonance Imaging (MRI) as possible predictors of cognitive outcome following rehabilitation therapy in children with acquired brain injury (ABI).

METHODS

Twenty-one children (10 boys, mean age 11.6 years, range 7.1-19.4) with stroke or traumatic brain injury underwent MRI including Diffusion Tensor Imaging (DTI) before admission to the rehabilitation centre. The conventional images were scored according to a standardised injury scoring system, and mean Fractional Anisotropy (FA) was determined within the Corpus Callosum (CC), as this structure is hypothesised to play an important role in cognition. Both conventional MRI injury scores and mean FA of the CC and its sub-regions were compared with standard functional cognitive outcome scores. Relationships between MRI indices and cognitive outcome scores were assessed using multiple regression and receiver operating characteristic (ROC) analyses.

RESULTS

A backwards regression analysis revealed that the mean FA of the CC body and genu and the supratentorial injury score appear to represent the best predictors of outcome, together with the age at rehabilitation and time in rehabilitation. In the ROC analysis, the mean FA values of the CC body and genu and the infratentorial injury score provided the highest sensitivity, while the mean FA of the CC splenium showed the highest specificity for outcome.

CONCLUSIONS

The conventional MRI injury scores and DTI metrics from the CC reflect cognitive outcomes following rehabilitation. Neuroimaging methods such as MRI with DTI may therefore provide important markers for cognitive recovery after brain injury.

Secondary injury to distal regions after intracerebral hemorrhage influence neurological functional outcome

Although many studies have focused on functional impairment after intracerebral hemorrhage, little is known about the relationship between secondary injuries to distal regions and neurological function. Our study aimed to evaluate the secondary injuries after intracerebral hemorrhage and explore their relationship to neurological functional outcome. Twenty-one patients with hemorrhages in supratentorial, deep locations and 10 healthy subjects were recruited. Longitudinal examinations of diffusion tensor imaging, hydrogen proton magnetic resonance spectroscopy imaging and neuropsychological assessment were performed after weeks 1 and 12 to elucidate the relationship between magnetic resonance imaging parameters and neurologic outcomes. By week 12, motor function had significantly improved, but cognitive function had deteriorated compared to week 1. Fractional anisotropy values for the ipsilateral cerebral peduncle correlated with motor function at week 1. No significant correlation between fractional anisotropy for the ipsilateral cerebral peduncle and the Fugl-Meyer Motor Scale was found at week 12. Fractional anisotropy values for the ipsilateral hippocampus were related to the Montreal Cognitive Assessment and Mini-Mental State Examination at weeks 1 and 12. Deep supratentorial hemorrhage may result in injury to distal regions, which correlate with impaired motor and cognitive function.

Inhibition of Mitochondrial ROS by MitoQ Alleviates White Matter Injury and Improves Outcomes after Intracerebral Haemorrhage in Mice

White matter injury (WMI) is an important cause of high disability after intracerebral haemorrhage (ICH). It is widely accepted that reactive oxygen species (ROS) contributes to WMI, but there is still no evidence-based treatment. Here, mitoquinone (MitoQ), a newly developed selective mitochondrial ROS scavenger, was used to test its neuroprotective potential. The data showed that MitoQ attenuated motor function deficits and motor-evoked potential (MEP) latency prolongation. Further research found that MitoQ blunted the loss of oligodendrocytes and oligodendrocyte precursor cells, therefore reduced demyelination and axon swelling after ICH. In the in vitro experiments, MitoQ, but not the nonselective antioxidant, almost completely attenuated the iron-induced membrane potential decrease and cell death. Mechanistically, MitoQ blocked the ATP deletion and mitochondrial ROS overproduction. The present study demonstrates that the selective mitochondrial ROS scavenger MitoQ may improve the efficacy of antioxidant treatment of ICH by white matter injury alleviation.

Modified behavioural tests to detect white matter injury- induced motor deficits after intracerebral haemorrhage in mice

Motor function deficit induced by white matter injury (WMI) is one of the most severe complications of intracerebral haemorrhage (ICH). The degree of WMI is closely related to the prognosis of patients after ICH. However, the current behavioural assessment of motor function used in the ICH mouse model is mainly based on that for ischaemic stroke and lacks the behavioural methods that accurately respond to WMI. Here, a series of easy-to-implement behavioural tests were performed to detect motor deficits in mice after ICH. The results showed that the grip strength test and the modified pole test not only can better distinguish the degree of motor dysfunction between different volumes of blood ICH models than the Basso Mouse Scale and the beam walking test but can also accurately reflect the severity of WMI characterized by demyelination, axonal swelling and the latency of motor-evoked potential delay induced by ICH. In addition, after ICH, the results of grip tests and modified pole tests, rather than the Basso Mouse Scale and the beam walking test, were worse than those observed after intraventricular haemorrhage (IVH), which was used as a model of brain haemorrhage in non-white matter areas. These results indicate that the grip strength test and the modified pole test have advantages in detecting the degree of motor deficit induced by white matter injury after ICH in mice.

Comparison of Fractional Anisotropy from Tract-Based Spatial Statistics with and without Lesion Masking in Patients with Intracerebral Hemorrhage: A Technical Note

BACKGROUND

Diffusion-tensor fractional anisotropy (FA) is an index of neural-fiber damage in patients following stroke. To better characterize FA, tract-based spatial statistics (TBSS) is frequently used, which involves spatial transformation into the standard brain space. Despite its utility, this technique is susceptible to space-occupying hematoma in patients with intracerebral hemorrhage. To correct this, "lesion making" has been proposed. Here, FA values from TBSS without lesion masking and TBSS with lesion masking were compared, and the clinical utility was evaluated.

METHODS

Forty patients from our previously published work were entered into the study. Diffusion-tensor imagings were acquired 14-21 days after onset and FA maps were generated. Lesion masks were produced in reference with nondiffusion (b = 0) brain images. Two types (with or without lesion masking) of TBSS were then performed. For both types, using individual data we extracted mean FA values within for the corticospinal tract (CST) and the superior longitudinal fasciculus (SLF). FA ratio (rFA) between the lesioned hemisphere and the unaffected hemisphere was then calculated. The two sets of the data were then compared by assessing residuals of mean root sum square error (RMSE).

RESULTS

Although rFA obtained from TBSS with lesion masking tended to be slightly smaller, the estimated RMSE was .025 for both the CST and the SLF.

CONCLUSIONS

The estimated FA differences between the two sets of TBSS were very small. Considering the time for manual labor for producing lesion masks, regular TBSS without lesion masking may be sufficient in terms of clinical utility.

Diffusion Tensor Imaging Biomarkers to Predict Motor Outcomes in Stroke: A Narrative Review

Stroke is a leading cause of disability worldwide. Motor impairments occur in most of the patients with stroke in the acute phase and contribute substantially to disability. Diffusion tensor imaging (DTI) biomarkers such as fractional anisotropy (FA) measured at an early phase after stroke have emerged as potential predictors of motor recovery. In this narrative review, we: (1) review key concepts of diffusion MRI (dMRI); (2) present an overview of state-of-art methodological aspects of data collection, analysis and reporting; and (3) critically review challenges of DTI in stroke as well as results of studies that investigated the correlation between DTI metrics within the corticospinal tract and motor outcomes at different stages after stroke. We reviewed studies published between January, 2008 and December, 2018, that reported correlations between DTI metrics collected within the first 24 h (hyperacute), 2-7 days (acute), and >7-90 days (early subacute) after stroke. Nineteen studies were included. Our review shows that there is no consensus about gold standards for DTI data collection or processing. We found great methodological differences across studies that evaluated DTI metrics within the corticospinal tract. Despite heterogeneity in stroke lesions and analysis approaches, the majority of studies reported significant correlations between DTI biomarkers and motor impairments. It remains to be determined whether DTI results could enhance the predictive value of motor disability models based on clinical and neurophysiological variables.

Predicting Motor Outcome in Acute Intracerebral Hemorrhage

BACKGROUND AND PURPOSE

Predicting motor outcome following intracerebral hemorrhage is challenging. We tested whether the combination of clinical scores and DTI-based assessment of corticospinal tract damage within the first 12 hours of symptom onset after intracerebral hemorrhage predicts motor outcome at 3 months.

MATERIALS AND METHODS

We prospectively studied patients with motor deficits secondary to primary intracerebral hemorrhage within the first 12 hours of symptom onset. Patients underwent multimodal MR imaging including DTI. We assessed intracerebral hemorrhage and perihematomal edema location and volume, and corticospinal tract involvement. The corticospinal tract was considered affected when the tractogram passed through the intracerebral hemorrhage or/and the perihematomal edema. We also calculated affected corticospinal tract-to-unaffected corticospinal tract ratios for fractional anisotropy, mean diffusivity, and axial and radial diffusivities. Motor impairment was graded by the motor subindex scores of the modified NIHSS. Motor outcome at 3 months was classified as good (modified NIHSS 0-3) or poor (modified NIHSS 4-8).

RESULTS

Of 62 patients, 43 were included. At admission, the median NIHSS score was 13 (interquartile range = 8-17), and the median modified NIHSS score was 5 (interquartile range = 2-8). At 3 months, 13 (30.23%) had poor motor outcome. Significant independent predictors of motor outcome were NIHSS and modified NIHSS at admission, posterior limb of the internal capsule involvement by intracerebral hemorrhage at admission, intracerebral hemorrhage volume at admission, 72-hour NIHSS, and 72-hour modified NIHSS. The sensitivity, specificity, and positive and negative predictive values for poor motor outcome at 3 months by a combined modified NIHSS of >6 and posterior limb of the internal capsule involvement in the first 12 hours from symptom onset were 84%, 79%, 65%, and 92%, respectively (area under the curve = 0.89; 95% CI, 0.78-1).

CONCLUSIONS

Combined assessment of motor function and posterior limb of the internal capsule damage during acute intracerebral hemorrhage accurately predicts motor outcome.

Computed tomography angiography-based analysis of high-risk intracerebral haemorrhage patients by employing a mathematical model

Background

Haemorrhagic stroke accounts for approximately 31.52% of all stroke cases, and the most common origin is hypertension. However, little is known about the method to identify high-risk populations of hypertensive intracerebral haemorrhage.

Results

The results showed that the angle between the middle cerebral artery and the internal carotid artery (AMIC), the distance between the beginning of the median artery and superior trunk (DMS), and the density (CT value) of the lenticulostriate artery (CTL) were statistically significant enough to cause intracerebral haemorrhage. In addition, we chose these three potential features for the ensemble learning classification model. Our developed ensemble-learning method outperforms not only previous work but also three other classic classification methods based on accuracy measurements.

Conclusions

The developed mathematical model in the present study is efficient in predicting the probability of intracerebral haemorrhage.

Electronic supplementary material

The online version of this article (10.1186/s12859-019-2741-5) contains supplementary material, which is available to authorized users.

Proprioception and motor performance after stroke: An examination of diffusion properties in sensory and motor pathways

Proprioceptive and motor impairments commonly occur after stroke. Relationships between corticospinal tract (CST) fractional anisotropy (FA) and motor recovery have been identified. However, the relationship between sensory tract microstructure and proprioceptive recovery remains unexplored. Using probabilistic tractography, we examined the relationship between diffusion metrics in three tracts known to contain proprioceptive information (a) dorsal-column medial-lemniscal (DCML), (b) postcentral gyrus to supramarginal gyrus (POCG-SMG), (c) postcentral gyrus to Heschl's gyrus (POCG-HG) and proprioception at 1 (n = 26) and 6 months (n = 19) poststroke. Proprioception was assessed using two robotic tasks. Motor performance was also assessed robotically and compared to CST diffusion metrics. At 1-month poststroke, a nonsignificant relationship (r = -0.43, p = 0.05) was observed between DCML-FA and proprioceptive impairment. A moderate relationship was identified between POCG-SMG FA and POCG-HG FA and proprioceptive impairment (r = -0.47, p = 0.001 and r = -0.51, p = 0.008, respectively). No relationships were significant at 6 months poststroke. Similar to previous studies, lower CST-FA correlated with motor impairment at 1 month poststroke (r = -0.58, p = 0.002). While CST-FA is considered a predictor of motor impairment, our findings suggest that the relationship between FA and tracts containing proprioceptive information is not as straightforward and highlights the importance of sensory association areas in proprioception.

Intracerebral hemorrhage outcome: A comprehensive update

Non-traumatic intracerebral hemorrhage (ICH) is associated with a significant global burden of disease, and despite being proportionally less frequent than ischemic stroke, in 2010 it was associated with greater worldwide disability-adjusted life years lost. The focus of outcome assessment after ICH has been mortality in most studies, because of the high early case fatality which reaches 40% in some population-based studies. The most robust and consistent predictors of early mortality include age, severity of neurological impairment, hemorrhage volume and antithrombotic therapy at the time of the event. Long-term outcome assessment is multifaceted and includes not only mortality and functional outcome, but also patient self-assessment of the health-related quality of life, occurrence of cognitive impairment, psychiatric disorders, epileptic seizures, recurrent ICH and subsequent thromboembolic events. Several scores which predict mortality and functional outcome after ICH have been validated and are useful in the daily clinical practice, however they must be used in combination with the clinical judgment for individualized patients. Management of patients with ICH both in the acute and chronic phases, requires health care professionals to have a comprehensive and updated perspective on outcome, which informs decisions that are needed to be taken together with the patient and next of kin.

Diffusion tensor imaging predicts motor outcome in children with acquired brain injury

BACKGROUND

Rehabilitation in children with acquired brain injury is a challenging endeavour. There is a large variability in motor recovery between patients, and a need to optimize therapies by exploiting cerebral plasticity and recovery mechanisms. This retrospective study aims to identify tract-based markers that could serve as predictors of functional outcome following rehabilitation.

METHODS

Twenty-nine children with traumatic brain injury (n = 14) or stroke (n = 15) underwent a 3 T Magnetic Resonance Imaging (MRI) measurement, including Diffusion Tensor Imaging (DTI) between admission to the Hospital and onset of rehabilitation therapy at the Rehabilitation Centre. The Functional Independence Measure for Children (WeeFIM) was routinely applied at admission and discharge from the Rehabilitation Centre. Distinguishing between children with good versus poor functional independence was performed using ROC-analysis. A non-parametric partial correlation analysis between the DTI and WeeFIM motor scores was performed with age, time in rehabilitation, and time of MRI scan after injury as covariates.

RESULTS

Mean fractional anisotropy (FA) from the DTI in the ipsilesional corticospinal-tract provided the highest predictive accuracy (sensitivity = 95 %, specificity = 78 %, Youden Index = 0.73, Area under the curve = 0.9), in comparison to the lesion volume or other clinical variables. Mean FA of the ipsilesional corticospinal-tract correlated positively with the WeeFIM discharge motor scores (ρ = 0.547, p = 0.004). Prediction was poorer for the lesion volume or Glasgow Coma Scale.

CONCLUSION

The results suggest that DTI data could improve the prediction of functional outcome after rehabilitation in children and adolescents with stroke or traumatic brain injury. Specifically, mean FA shows the highest predictive accuracy in comparison to lesion volume or clinical scales.

Disrupted focal white matter integrity in autism spectrum disorder: A voxel-based meta-analysis of diffusion tensor imaging studies

BACKGROUND

Autism spectrum disorder (ASD) is a mental disorder that has long been considered to result from brain underconnectivity. However, volumetric analysis of structural MRI data has failed to find consistent white matter alterations in patients with ASD. The present study aims to examine whether there are consistent focal white matter alterations as measured by diffusion tensor imaging (DTI) in individuals with ASD compared with typically developing (TD) individuals.

METHOD

Coordinate-based meta-analysis was performed on 14 studies that reported fractional anisotropy (FA) alterations between individuals with ASD and TD individuals. These studies have in total 297 subjects with ASD and 302 TD subjects.

RESULTS

Activation likelihood estimation (ALE) analysis identified two clusters of white matter regions that showed consistent reduction of FA in individuals with ASD compared with TD individuals: the left splenium of corpus callosum and the right cerebral peduncle.

CONCLUSIONS

Consistent focal white matter reductions in ASD could be identified by using FA, highlighting the cerebral peduncle which is usually overlooked in studies focusing on major white matter tracts. These focal reductions in the splenium and the cerebral peduncle may be associated with sensorimotor impairments seen in individuals with ASD.

Utility of Fractional Anisotropy in Cerebral Peduncle for Stroke Outcome Prediction: Comparison of Hemorrhagic and Ischemic Strokes

BACKGROUND

Diffusion-tensor fractional anisotropy (FA) has been used for predicting stroke outcome. However, most previous studies focused on patients with either hemorrhagic or ischemic stroke. The aim of this study was to assess the correlation between FA and outcome for patients with hemorrhagic stroke and those with ischemic stroke, and then compare their correlation patterns.

METHODS

This study sampled 40 hemorrhagic and 40 ischemic stroke patients from our previously published reports. Diffusion-tensor images were obtained on days 14-21, and FA images were generated, after which the ratio of FA within the cerebral peduncles of the affected and unaffected hemispheres (rFA) was calculated. Outcome was assessed using Brunnstrom stage (BRS), motor component of the functional independence measure (FIM-motor), and total length of hospital stay (LOS) at discharge from our affiliated rehabilitation hospital. The data were then compared between the hemorrhage and the infarct groups. Correlation analyses between rFA and outcome assessments were performed separately for both groups and then were compared between the groups.

RESULTS

The hemorrhage group exhibited significantly more severe BRS, longer LOS, and lower rFA than the infarct group. The correlations between rFA and outcome measures were all statistically significant for both the hemorrhage and the infarct groups. The correlation patterns for BRS and LOS were very similar between the hemorrhage and the infarct groups. However, such similarity was not evident for FIM-motor.

CONCLUSIONS

FA in the cerebral peduncles may be used to predict extremity functions and LOS for both types of stroke.

Management of Spontaneous Intracerebral Hematoma

The incidence of spontaneous intracerebral hematoma (SICH) is even now high worldwide, especially higher in Japan than in Western countries, despite the development of advances in blood pressure (BP) management and food/alcohol intake education. Although mortality and morbidity for SICH are high, some controversies remain regarding the appropriate acute phase of treatment. Recent studies have revealed that BP lowering treatment than 140 mmHg resulted in better outcomes. However the efficacy of surgical treatment for SICH has not been well established, with the exception of that for cerebellar SICH over 3 cm in diameter and life-saving procedures, although many randomized control studies and systematic reviews focused on surgical treatment have been reported. In this review, we summarize some issues and discuss strategies in development for the treatment of SICH.

Multimodality MRI assessment of grey and white matter injury and blood-brain barrier disruption after intracerebral haemorrhage in mice

In this study, we examined injury progression after intracerebral haemorrhage (ICH) induced by collagenase in mice using a preclinical 11.7 Tesla MRI system. On T2-weighted MRI, lesion and striatal volumes were increased on day 3 and then decreased from days 7 to 28. On day 3, with an increase in striatal water content, vasogenic oedema in the perihaematomal region presented as increased T2 and increased apparent diffusion coefficient (ADC) signal. With a synchronous change in T2 and ADC signals, microglial activation peaked on day 3 in the same region and decreased over time. Iron deposition appeared on day 3 around the haematoma border but did not change synchronously with ADC signals. Vascular permeability measured by Evans blue extravasation on days 1, 3, and 7 correlated with the T1-gadolinium results, both of which peaked on day 3. On diffusion tensor imaging, white matter injury was prominent in the corpus callosum and internal capsule on day 3 and then partially recovered over time. Our results indicate that the evolution of grey/white matter injury and blood-brain barrier disruption after ICH can be assessed with multimodal MRI, and that perihaematomal vasogenic oedema might be attributable to microglial activation, iron deposition, and blood-brain barrier breakdown.

Minimally Invasive Surgery for Evacuating the Intracerebral Hematoma in Early Stages Decreased Secondary Damages to the Internal Capsule in Dog Model of ICH Observed by Diffusion Tensor Imaging

BACKGROUND

Diffusion tensor imaging was used to observe the effects of performing early minimally invasive surgery (MIS) on internal capsule in dog model of intracerebral hemorrhage (ICH).

METHODS

Twenty-five male dogs were selected to prepare an ICH model, and then they were randomly distributed into a model control (MC) group (5 dogs) or an MIS group (20 dogs). In the MIS group, the intracerebral hematoma was evacuated by stereotactic minimally invasive procedures over 6 hours (5 dogs), 12 hours (5 dogs), 18 hours (5 dogs), or 24 hours (5 dogs) after successful induction of ICH. The same procedure was performed in the MC group but without evacuating the hematoma. All the animals were sacrificed within 2 weeks after the hematoma was surgically evacuated. The neurologic deficit score and diffusion tensor imaging (DTI) were observed before and after the MIS. The perihematomal blood-brain barrier (BBB) permeability and the brain water content (BWC) were measured 2 weeks after the hematoma was surgically evacuated.

RESULTS

The DTI demonstrated that integrity of the internal capsule restored largely after surgery and the fractional anisotropy (FA) values of the internal capsule on the hematoma side increased significantly as compared with those in the MC group or those before surgery in the same group. The postoperative ratios of FA values of each MIS subgroup increased compared with the MC group and those before surgery in the same subgroup before operation. The neurologic deficit score, the perihematomal BBB permeability, and the BWC of each MIS subgroup decreased significantly compared with those of the MC group. The 6-12-hour group displayed a more favorable result.

CONCLUSIONS

Performing the MIS in the early stage (6-12 hours) after ICH could decrease the secondary damages to the internal capsule so as to promote the recovery of motor function. The optimal time window for MIS should be within 6-12 hours after onset of ICH.

[Prоgnosis of motor function recovery in ischemic stroke using diffusion tensor MRI]

AIM

To identify factors of motor recovery in ischemic stroke (IS) using diffusion tensor imaging (DTI).

MATERIAL AND METHODS

Forty-seven patients with IS were studied within 1-2, 7-8, 14-15, 20-21 days after stroke. The fractional anisotropy (FA) values of the pyramidal tract were measured in the posterior limb of the internal capsule, cerebral peduncle and pons. Relative values of FA (rFA) ratio (rFA=FA affected side/FA unaffected side) were assessed as well.

RESULTS

rFA≤0.7 in the cerebral peduncule and posterior limb of the internal capsule accurately predicted poor motor outcome in ischemic stroke.

CONCLUSION

DTI can evaluate the motor deficit quantitatively and may predict the functional prognosis in patients with IS.

MRI Biomarkers for Hand-Motor Outcome Prediction and Therapy Monitoring following Stroke

Several biomarkers have been identified which enable a considerable prediction of hand-motor outcome after cerebral damage already in the subacute stage after stroke. We here review the value of MRI biomarkers in the evaluation of corticospinal integrity and functional recruitment of motor resources. Many of the functional imaging parameters are not feasible early after stroke or for patients with high impairment and low compliance. Whereas functional connectivity parameters have demonstrated varying results on their predictive value for hand-motor outcome, corticospinal integrity evaluation using structural imaging showed robust and high predictive power for patients with different levels of impairment. Although this is indicative of an overall higher value of structural imaging for prediction, we suggest that this variation be explained by structure and function relationships. To gain more insight into the recovering brain, not only one biomarker is needed. We rather argue for a combination of different measures in an algorithm to classify fine-graded subgroups of patients. Approaches to determining biomarkers have to take into account the established markers to provide further information on certain subgroups. Assessing the best therapy approaches for individual patients will become more feasible as these subgroups become specified in more detail. This procedure will help to considerably save resources and optimize neurorehabilitative therapy.

Can Neurological Biomarkers of Brain Impairment Be Used to Predict Poststroke Motor Recovery? A Systematic Review

Background There is growing interest to establish recovery biomarkers, especially neurological biomarkers, in order to develop new therapies and prediction models for the promotion of stroke rehabilitation and recovery. However, there is no consensus among the neurorehabilitation community about which biomarker(s) have the highest predictive value for motor recovery. Objective To review the evidence and determine which neurological biomarker(s) meet the high evidence quality criteria for use in predicting motor recovery. Methods We searched databases for prognostic neuroimaging/neurophysiological studies. Methodological quality of each study was assessed using a previously employed comprehensive 15-item rating system. Furthermore, we used the GRADE approach and ranked the overall evidence quality for each category of neurologic biomarker. Results Seventy-one articles met our inclusion criteria; 5 categories of neurologic biomarkers were identified: diffusion tensor imaging (DTI), transcranial magnetic stimulation (TMS), functional magnetic resonance imaging (fMRI), conventional structural MRI (sMRI), and a combination of these biomarkers. Most studies were conducted with individuals after ischemic stroke in the acute and/or subacute stage (~70%). Less than one-third of the studies (21/71) were assessed with satisfactory methodological quality (80% or more of total quality score). Conventional structural MRI and the combination biomarker categories ranked "high" in overall evidence quality. Conclusions There were 3 prevalent methodological limitations: (a) lack of cross-validation, (b) lack of minimal clinically important difference (MCID) for motor outcomes, and (c) small sample size. More high-quality studies are needed to establish which neurological biomarkers are the best predictors of motor recovery after stroke. Finally, the quarter-century old methodological quality tool used here should be updated by inclusion of more contemporary methods and statistical approaches.

Prediction of upper extremity motor recovery after subacute intracerebral hemorrhage through diffusion tensor imaging: a systematic review and meta-analysis

INTRODUCTION

Early assessment of the pyramidal tracts is important for intracerebral hemorrhage (ICH) patients in order to decide the optimal treatment or to assess appropriate rehabilitation strategies, and management of patient expectations and goals. The purpose of this study was to systematically review and summarize the current available literature on the value of Fractional Anisotropy (FA) parameter of the diffusion tensor imaging (DTI) in predicting upper extremity (UE) motor recovery after subacute ICH.

METHODS

PubMed, EMBASE, MEDLINE, Google Scholar, and Cochrane CENTRAL searches were conducted from 1 January 1950 to 31 March 2016 which were supplemented with relevant articles identified in the references. Pooled estimate using correlation between DTI parameter FA and UE motor recovery was done using comprehensive meta-analysis software.

RESULTS

Out of 97 citations, only eight studies met the criteria for inclusion in the systematic review and six studies were included in the meta-analysis. A random effects model revealed that DTI parameter FA is a significant predictor for UE motor recovery after subacute ICH (correlation coefficient = 0.56; 95 % confidence interval 0.44 to 0.65, P value <0.001). However, moderate heterogeneity was observed between the studies (Tau-squared = 0.28, I-squared = 70.3).

CONCLUSION

The studies reported so far on correlation between FA parameter of DTI and UE motor recovery in ICH patients are few with small sample sizes. This meta-analysis suggests a strong correlation between DTI parameter FA and UE motor recovery in ICH patients. Further well-designed prospective studies embedded with larger sample size are needed to confirm these findings.

Dynamic Diffusion Tensor Imaging Reveals Structural Changes in the Bilateral Pyramidal Tracts after Brain Stem Hemorrhage in Rats

BACKGROUND AND PURPOSE

Few studies have concentrated on pyramidal tract (PY) changes after brain stem hemorrhage (BSH). In this study, we used a diffusion tensor imaging (DTI) technique and histologic identification to investigate longitudinal PY changes on both the contralateral and ipsilateral sides after experimental BSH.

METHODS

BSH was induced in 61 Sprague-Dawley rats by infusing 30 μl of autogenous tail blood into each rat's right pons. DTI and motor function examinations were performed repeatedly on days 1, 3, 7, 14, and 28 after surgery. Fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity were measured in the bilateral PYs. The axon and myelin injury in the PY were evaluated by histologic study.

RESULTS

As compared with normal controls, the bilateral PYs in rats with induced BSH showed an early decrease and a late increase in FA and an early increase and a late decrease in MD. A progressive decrease in axial diffusivity with dramatic axon loss from day 1 to day 28 after BSH was found bilaterally. The bilateral PYs showed an early increase and a late decrease in radial diffusivity. Early myelin injury and late repair were also detected pathologically in the bilateral PYs of rats with BSH. Thus, the early motor function deficits of rats with BSH began to improve on day 14 and had almost completely disappeared by day 28.

CONCLUSIONS

DTI revealed dynamic changes in the bilateral PYs after BSH, which was confirmed by histologic findings and which correlated with motor function alteration. These findings support the idea that quantitative DTI can track structural changes in the bilateral PYs and that DTI may serve as a noninvasive tool to predict the prognoses of patients with BSH.