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White matter tracts within the central nervous system are organized into ascending and descending pathways that transmit sensory input and motor output, respectively. Tractopathy, or damage to these tracts, can impair sensory or motor functions. Motor neuron diseases are pathologic processes affecting the upper or lower motor neurons. Amyotrophic lateral sclerosis (ALS) is the most common form of acquired motor neuron disease. Traditionally, ALS has affected upper and lower motor neurons of the extremities, torso, and head and neck. There are several ALS variants, some of which affect only the upper motor neurons (eg, primary lateral sclerosis), lower motor neurons (eg, progressive muscular atrophy), or motor neurons of the head and neck (eg, progressive bulbar palsy). Characteristic imaging features of ALS include abnormal T2 hyperintensity within the brain along the corticospinal tract, as well as cortical susceptibility signal intensity along the precentral gyrus, termed the "motor band" sign. Spinal muscular atrophy is a less common primary motor neuron disease and appears on images as atrophy of the anterior horn of the spinal cord, as well as proximal muscle atrophy. In addition to pure motor neuron diseases, there are numerous toxic and metabolic conditions, genetic disorders, infectious diseases, and immune-mediated disorders that can secondarily affect the corticospinal tracts (corticospinal tractopathies), producing symptoms of upper motor neuron injury. These tractopathies are visible at MRI as T2-hyperintense lesions along varying segments of the corticospinal tract. A comprehensive diagnostic approach that integrates clinical symptoms with radiologic and laboratory findings is crucial to distinguish among these varied conditions. © RSNA, 2024 Supplemental material is available for this article.

Background: Evaluation of the structural integrity and functional excitability of the corticospinal tract (CST) is likely to be important in predicting motor recovery after stroke. Previous reports are inconsistent regarding a possible link between CST structure and CST function in this setting. This study aims to investigate the structure‒function relationship of the CST at the acute phase of stroke (<7 days)., Methods: We enrolled 70 patients who had an acute ischaemic stroke with unilateral upper extremity (UE) weakness. They underwent a multimodal assessment including clinical severity (UE Fugl Meyer at day 7 and 3 months), MRI to evaluate the CST lesion load and transcranial magnetic stimulation to measure the maximum amplitude of motor evoked potential (MEP)., Results: A cross-sectional lesion load above 87% predicted the absence of MEPs with an accuracy of 80.4%. In MEP-positive patients, the CST structure/function relationship was bimodal with a switch from a linear relationship (rho=-0.600, 95% CI -0.873; -0.039, p<0.03) for small MEP amplitudes (<0.703 mV) to a non-linear relationship for higher MEP amplitudes (p=0.72). In MEP-positive patients, recovery correlated with initial severity. In patients with a positive MEP <0.703 mV but not in patients with an MEP ≥0.703 mV, MEP amplitude was an additional independent predictor of recovery. In MEP-negative patients, we failed to identify any factor predicting recovery., Conclusion: This large multimodal study on the structure/function of the CST and stroke recovery proposes a paradigm change for the MEP-positive patients phenotypes and refines the nature of the link between structural integrity and neurophysiological function, with implications for study design and prognostic information., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2025. No commercial re-use. See rights and permissions. Published by BMJ Group.)

Abstract: A teenager who suffered from left hemiparesis after traumatic brain injury underwent 18F-THK5351 PET 48, 286, and 810 days after the injury. The first scan showed slight uptake in the right corticospinal tract (CST), and the second scan showed intense uptake along the CST, which was significantly reduced in the third scan. The hemiparesis has improved between the first and second scans. 18F-THK5351 binds to monoamine oxidase B, which is expressed in reactive astrocytes (RAs). Recently, the beneficial role of RAs in plasticity and reconstruction after traumatic brain injury has been reported. 18F-THK5351 uptake may represent axonal remodeling accompanied with RAs in the CST., Competing Interests: Conflicts of interest and sources of funding: none declared., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Nearly half of the amyotrophic lateral sclerosis (ALS) patients showed hyperintensity of the corticospinal tract (CST+), yet whether brain functional pattern differs between CST+and CST- patients remains obscure. In the current study, 19 ALS CST+, 41 ALS CST- patients and 37 healthy controls (HC) underwent resting state fMRI scans. We estimated local activity and connectivity patterns via the Amplitude of Low Frequency Fluctuations (ALFF) and the Network-Based Statistic (NBS) approaches respectively. The ALS CST+patients did not differ from the CST- patients in amyotrophic lateral sclerosis functional rating scale revised (ALSFRS-R) score and disease duration. ALFF of the superior frontal gyrus (SFG) and the inferior frontal gyrus pars opercularis (OIFG) were highest in the HC and lowest in the ALS CST- patients, resulting in significant group differences (P FWE <0.05). NBS analysis revealed a frontal network consisting of connections between SFG, OIFG, orbital frontal gyrus, middle cingulate cortex and the basal ganglia, which exhibited HC>ALS CST+ > ALS CST- group differences (P FWE =0.037) as well. The ALFF of the OIFG was significantly correlated with ALSFRS-R (R=0.34, P=0.028) and mean connectivity of the frontal network was trend-wise significantly correlated with disease duration (R=-0.31, P=0.052) in the ALS CST- patients. However, these correlations were insignificant in ALS CST+patients (P values > 0.8). In conclusion, The ALS CST+patients exhibited different patterns of baseline functional activity and connectivity in the frontal cortex which may indicate a functional compensatory effect., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: There is limited information on brain perfusion single-photon emission computed tomography (SPECT) findings related to motor outcomes in patients with stroke. We aimed to investigate whether brain SPECT can be used to determine motor outcomes after corona radiata infarction., Methods: Eighty-nine patients were recruited in this study. Brain SPECT and diffusion tensor tractography (DTT) were conducted to evaluate the state of the corticospinal tract (CST) within 7-30 days of corona radiata infarct. Motor outcome was measured 6 months after infarct onset and was evaluated using the modified Brunnstrom classification (MBC) and functional ambulation category (FAC) for motor function of the upper and lower extremities, respectively. The presence of hypoperfusion on brain SPECT was evaluated in the frontal lobe, temporal lobe, parietal lobe, basal ganglia, thalamus, and cerebellum on both the ipsilesional and contralesional sides. Statistical analysis was performed using multivariate logistic regression, comparing patients in which CST was spared versus interrupted., Results: Hypoperfusion in the contralesional cerebellum was indicative of poor recovery in both the upper and lower extremities after corona radiata infarction when the CST was interrupted. Additionally, when the CST was preserved, hypoperfusion in the ipsilesional thalamus was indicative of poor recovery of the lower extremities., Conclusion: Brain SPECT evaluation was shown to be a useful tool for predicting motor outcomes in patients with corona radiata infarcts.

We report an autopsy case of a 70-year-old man who was clinically diagnosed with atypical progressive supranuclear palsy (PSP). He initially presented with gait ataxia and then showed vertical gaze palsy, rigidity, akinesia, dysphagia, and mild cognitive impairment, followed by prominent upper motor signs later in the course of the disease. Cranial magnetic resonance imaging revealed tegmental atrophy of the midbrain. Autopsy revealed severe neuronal loss and gliosis in the motor cortex and corticospinal degeneration and mild to moderate neuronal loss and gliosis in the basal ganglia, substantia nigra, midbrain, and pons. Tufted astrocytes were primarily found in the motor cortex and basal ganglia. Globose-type neurofibrillary tangles were observed in the locus coeruleus and nucleus olivaris inferior. In the cerebellar cortex, mild Purkinje cell loss and scattered axonal torpedoes were observed with tau-positive Purkinje cells. The dentate nucleus displayed severe neuronal loss and gliosis. The present case showed characteristics of both PSP with prominent cerebellar ataxia (PSP-C) and PSP-primary lateral sclerosis (PSP-PLS)., (© 2024 Japanese Society of Neuropathology.)

Background: Acute brainstem infarction is associated with high morbidity and mortality, the integrity of corticospinal tract (CST) detected via diffusion tensor imaging (DTI) can assist in predicting the motor recovery of the patients. In addition to the damage caused by ischemia and reperfusion, sterile inflammation also contributes to the brain injury after stroke. However, the changes in CST integrity detected by DTI in acute brainstem infarction have yet to be fully elucidated, and it is still unclear whether sterile inflammation can cause damage to the CST., Methods: In this study, the acute brainstem infarction patients in the early (EABI patients, n = 19) and late (LABI patients, n = 21) stages and healthy controls (HCs, n = 22) are employed. The probabilistic tractography technique was used and the fractional anisotropy (FA) value was chosen to evaluated the integrity of the CST, the IL-6, IL-10, IL-17, IL-1β, and tumor necrosis factor (TNF)-α levels in the plasma are measured to evaluate the level of inflammation., Results: Compared to the HCs (F = 13.634, p ANOVA < 0.001), the CST FA values on the infarcted side were abnormally elevated in EABI patients (p LSD = 0.003), and decreased in LABI patients (p LSD = 0.034). The levels of IL-6 (F = 12.311, p ANOVA < 0.001, EABI vs HCs: p LSD < 0.001, LABI vs HCs: p LSD < 0.001), IL-10 (F = 11.329, p ANOVA < 0.001, EABI vs HCs: p LSD < 0.001, LABI vs HCs: p LSD = 0.017) and IL-1β (F = 15.986, p ANOVA < 0.001, EABI vs HCs: p LSD < 0.001, LABI vs HCs: p LSD < 0.001) were increased in both EABI and LABI patients, while the IL-17 levels were elevated only in LABI patients (F = 4.258, p ANOVA = 0.019, LABI vs HCs: p LSD = 0.027). Among these cytokines, the increased IL-6 (r = 0.663, p = 0.002) and IL-1β (r = 0.615, p = 0.005) levels of EABI patients might be related to the elevated CST FA values, while the increased IL-17 (r = -0.599, p = 0.004) levels of LABI patients might contribute to the decrease of the CST FA values., Conclusion: Our study reveals that the increased CST FA values in EABI patients may include signals generated by the immune cells which move along the CST. The sterile inflammation may contribute to the impairment of CST integrity in LABI patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Shi, Chen, Ci, Geng, Qi, Chen and Yin.)

To determine diagnostic value of diffusion tensor imaging (DTI) in amyotrophic lateral sclerosis (ALS) patients and investigate the association between DTI and neurofilaments (NFs), including serum and cerebrospinal fluid (CSF) levels of neurofilament light chain (NFL) and phosphorylated neurofilament heavy chain (pNFH). Forty-three clinically diagnosed ALS patients and 32 control subjects without neurological disorders underwent routine MRI (magnetic resonance imaging) and DTI scans. DTI parameters (mean diffusivity [MD] and fractional anisotropy [FA]) at axial levels of internal capsules and cerebral peduncles along the corticospinal tract (CST) were measured. The study compared the differences of DTI parameters between ALS patients and controls using the Mann-Whitney U test. Diagnostic efficacy of each DTI metric was evaluated using the receiver operating characteristic (ROC) curve. NFs (NFL and pNFH levels in serum and CSF) were measured by enzyme-linked immunosorbent assay. Correlation analyses were conducted between DTI parameters and NFs. Capsule-MD and Peduncle-MD in ALS patients were higher than those in controls; whereas Capsule-FA and Peduncle-FA in ALS patients were lower than those in controls (all, p < 0.05). The area under curve (AUC) was 0.730 for Capsule-FA, 0.828 for Capsule-MD, 0.890 for Peduncle-FA, and 0.896 for Peduncle-MD. Capsule-FA was negatively correlated with CSF-NFL (r = - 0.813, p < 0.001), Serum-NFL (r = - 0.493, p = 0.001), CSF-pNFH (r = - 0.637, p < 0.001), and Serum-pNFH (r = - 0.672, p < 0.001); Peduncle-FA negatively with CSF-NFL (r = - 0.562, p < 0.001), CSF-pNFH (r = - 0.506, p = 0.001), and Serum-pNFH (r = - 0.488, p = 0.001); Peduncle-MD positively with CSF-NFL (r = 0.516, p < 0.001), CSF-pNFH (r = 0.494, p = 0.001). DTI had superior performance in identifying ALS patients and could serve as a reliable predictor. DTI parameters related to neurofilament markers, and Capsule-FA may become a robust surrogate biomarker indicating disease severity and progression rate for ALS patients., Competing Interests: Declarations Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Stroke is one of the leading causes of disability worldwide. Stroke-in-evolution is an essential issue as it is often associated with a worse outcome. Central motor conduction time (CMCT) is the time required for neural impulses to travel through the central nervous system to the target muscles. CMCT prolongation indicates dysfunction of the corticospinal tract. This study aims to investigate the impact of CMCT on clinical features and MRI characteristics in patients with acute ischemic stroke. A total of 94 patients with suspected acute ischemic stroke, with an average age of 67.13 ± 10.73 years old and 69.15 % being male, were enrolled in this study. All patients underwent evaluation for stroke risk factors, medical record review, CMCT examination (with CMCT (+) indicating CMCT prolongation), cranial MRI examinations, and data analysis. Compared to CMCT (-), the number of CMCT (+) subjects was significantly higher in all groups except the "Ever Stroke" group. The CMCT (+) group exhibited significantly higher values of "NIHSS" and "mRS" compared to the CMCT (-) group. After ANCOVA adjustment, the number of CMCT (+) subjects remained significantly higher only in the radiologically classified "New Pyramidal Lesion on MRI" and clinically classified "Stroke-In-Evolution" groups. In conclusion, CMCT serves as both a diagnostic indicator of acute ischemic stroke with weakness accompanied by new pyramidal lesions on brain MRI, rather than weakness associated with old lesions on brain MRI, and as a predictive marker for stroke progression during hospitalization., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Background: Insular low-grade gliomas (LGGs) are surgically challenging due to their proximity to critical structures like the corticospinal tract (CST)., Purpose: This study aims to determine if preoperative CST shape metrics correlate with postoperative motor complications in insular LGG patients., Study Type: Retrospective., Population: 42 patients (mean age 40.26 ± 10.21 years, 25 male) with insular LGGs., Field Strength/sequence: Imaging was performed using 3.0 Tesla MRI, incorporating T1-weighted magnetization-prepared rapid gradient-echo, T2-weighted space dark-fluid with spin echo (SE), and diffusional kurtosis imaging (DKI) with gradient echo sequences, all integrated with echo planar imaging., Assessment: Shape metrics of the CST, including span, irregularity, radius, and irregularity of end regions (RER and IER, respectively), were compared between the affected and healthy hemispheres. Total end region radius (TRER) was determined as the sum of RER 1 and RER 2. The relationships between shape metrics and postoperative short-term (4 weeks) and long-term (>8 weeks) motor disturbances assessing by British Medical Research Council grading system, was analyzed using multivariable regression models., Statistical Testing: Paired t-tests compared CST metrics between hemispheres. Logistic regression identified associations between these metrics and motor disturbances. The models were developed using all available data and there was no independent validation dataset. Significance was set at P < 0.05., Results: Short-term motor disturbance risk was significantly related to TRER (OR = 199.57). Long-term risk significantly correlated with IER 1 (OR = 59.84), confirmed as a significant marker with an AUC of 0.78. Furthermore, the CST on the affected side significantly had the greater irregularity, larger TRER and RER 1, and smaller span compared to the healthy side., Data Conclusion: Preoperative evaluation of TRER and IER 1 metrics in the CST may serve as a tool for assessing the risk of postoperative motor complications in insular LGG patients., Level of Evidence: 2 TECHNICAL EFFICACY: Stage 2., (© 2024 International Society for Magnetic Resonance in Medicine.)

To retrospectively explore the role of magnetic resonance imaging (MRI) diffusion tensor imaging (DTI) in analyzing the corticospinal tract injury in acute cerebral anterior circulation infarction in the basal ganglia region and the correlation between DTI parameters and neurological function scores, patients with acute cerebral infarction and stroke had undergone plain MRI and DTI sequence scanning were enrolled. Diffusion tensor tractography was used to perform 3-dimensional reconstruction of bilateral corticospinal tracts (CST). The image data were processed to obtain fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values, and the correlation between the DTI parameters and neurological function scores of National Institutes of Health Stroke Scale (NIHSS) was evaluated. A total of thirty-two patients with acute ischemic cerebral infarction were retrospectively enrolled, including 19 males and 13 females with a mean age 63.22 ± 7.78 years. The CST score was 0 in 2 (6.25%) patients, 1 in 9 (28.13%), 2 in 9 (28.13%), 3 in 7 (21.88%), and 4 in 5 (15.63%). The FA value significantly (P = .01) decreased (0.52 ± 0.03 vs 0.62 ± 0.04) on the ischemic side compared with that on the normal side. A significant (P < .05) difference was detected in the number of nerve fibers (223.3 ± 110.0 vs 246.7 ± 104.4) rather than in the ADC values (0.86 ± 0.06 vs 0.84 ± 0.06) between the ischemic and healthy sides. The FA and ADC values were not significantly (P > .05) different according to the CST scores 0, 1, 2, 3, or 4 between the ischemic and healthy sides. There was a significant (P < .05) negative correlation between the FA value on the infarcted side and the NIHSS score. In conclusion, with the DTI technology, varying degrees of damage to the corticospinal tract at the infarcted side can be detected and important clinical information can be provided for the diagnosis and prognosis of acute cerebral infarction by evaluating the degree of corticospinal tract injury., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

The concept of structural reserve in stroke reorganization assumes that the relevance of the contralesional hemisphere strongly depends on the brain tissue spared by the lesion in the affected hemisphere. Recent studies, however, have indicated that the contralesional hemisphere's impact exhibits region-specific variability with concurrently existing maladaptive and supportive influences. This challenges traditional views, necessitating a nuanced investigation of contralesional motor areas and their interaction with ipsilesional networks. Our study focused on the functional role of contralesional key motor areas and lesion-induced connectome disruption early after stroke. Online TMS data of twenty-five stroke patients was analyzed to disentangle interindividual differences in the functional roles of contralesional primary motor cortex (M1), dorsal premotor cortex (dPMC), and anterior interparietal sulcus (aIPS) for motor function. Connectome-based lesion symptom mapping and corticospinal tract lesion quantification were used to investigate how TMS effects depend on ipsilesional structural network properties. At group and individual levels, TMS interference with contralesional M1 and aIPS but not dPMC led to improved performance early after stroke. At the connectome level, a more disturbing role of contralesional M1 was related to a more severe disruption of the structural integrity of ipsilesional M1 in the affected motor network. In contrast, a detrimental influence of contralesional aIPS was linked to less disruption of the ipsilesional M1 connectivity. Our findings indicate that contralesional areas distinctively interfere with motor performance early after stroke depending on ipsilesional structural integrity, extending the concept of structural reserve to regional specificity in recovery of function., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

Subtle motor signs are a common feature in children with attention-deficit/hyperactivity disorder (ADHD). It has long been suggested that white matter abnormalities may be involved in their presentation, though no study has directly probed this question. The aim of this study was to investigate the relationship between white matter organization and the severity of subtle motor signs in children with and without ADHD. Participants were 92 children with ADHD aged between 8 and 12 years, and 185 typically developing controls. Subtle motor signs were examined using the Physical and Neurological Examination for Soft Signs (PANESS). Children completed diffusion MRI, and fixel-based analysis was performed after preprocessing. Tracts of interest were delineated using TractSeg including the corpus callosum (CC), the bilateral corticospinal tracts (CST), superior longitudinal fasciculus, and fronto-pontine tracts (FPT). Fiber cross-section (FC) was calculated for each tract. Across all participants, lower FC in the CST was associated with higher PANESS Total score (greater motor deficits). Within the PANESS, similar effects were observed for Timed Left and Right maneuvers of the hands and feet, with lower FC of the CST, CC, and FPT associated with poorer performance. No significant group differences were observed in FC in white matter regions associated with PANESS performance. Our data are consistent with theoretical accounts implicating white matter organization in the expression of motor signs in childhood. However, rather than contributing uniquely to the increased severity of soft motor signs in those with ADHD, white matter appears to contribute to these symptoms in childhood in general., (© 2024 The Author(s). Human Brain Mapping published by Wiley Periodicals LLC.)

Objectives: Neuroimaging studies of dyskinetic cerebral palsy (CP) are scarce and the neuropathological underpinnings are not fully understood. We delineated the corticospinal tract (CST) and cortico-striatal-thalamocortical (CSTC) pathways with probabilistic tractography to assess their (1) integrity and (2) association with motor functioning in people with dyskinetic CP., Methods: Diffusion weighted magnetic resonance images were obtained for 33 individuals with dyskinetic CP and 33 controls. Fractional anisotropy (FA) and mean diffusivity (MD) for the CST and the CSTC pathways were compared between groups. Correlation analyses were performed between tensor metric values and motor function scores of participants with dyskinetic CP as assessed by the Gross Motor Function Classification System (GMFCS), the Bimanual Fine Motor Function (BFMF), and the Manual Ability Classification System (MACS)., Results: White matter integrity in both the CST and the CSTC pathways was reduced in people with dyskinetic CP. The GMFCS, MACS and, less commonly, the BFMF were associated with FA and, particularly, MD in most portions of these pathways., Interpretation: The present study advances our understanding of the involvement of white matter microstructure in sensorimotor pathways and its relationship with motor impairment in people with dyskinetic CP. Our results are consistent with well-described relationships between upper limb function and white matter integrity in the CST and CSTC pathways in other forms of CP. This knowledge may ultimately help prognosis and therapeutic programmes., (© 2024 The Author(s). Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Background and Objectives: Clinical factors are not sufficient to fix a prognosis of recovery after stroke. Pyramidal tract or alternate motor fiber (aMF: reticulo-, rubrospinal pathways and transcallosal fibers) integrity and remodeling processes assessable by diffusion tensor MRI (DTI) and voxel-based morphometry (VBM) may be of interest. The primary objective was to study longitudinal cortical brain changes using VBM and longitudinal corticospinal tract changes using DTI during the first 4 months after lacunar cerebral infarction. The second objective was to determine which changes were correlated to clinical improvement., Methods: Twenty-one patients with deep brain ischemic infarct with pure motor deficit (NIHSS score ≥ 2) were recruited at Purpan Hospital and included. Motor deficit was measured [Nine peg hole test (NPHT), dynamometer (DYN), Hand-Tapping Test (HTT)], and a 3T MRI scan (VBM and DTI) was performed during the acute and subacute phases., Results: White matter changes: corticospinal fractional anisotropy (FA CST ) was significantly reduced at follow-up (approximately 4 months) on the lesion side. FAr (FA ratio in affected/unaffected hemispheres) in the corona radiata was correlated to the motor performance at the NPHT, DYN, and HTT at follow-up. The presence of aMFs was not associated with the extent of recovery. Grey matter changes: VBM showed significant increased cortical thickness in the ipsilesional premotor cortex at follow-up. VBM changes in the anterior cingulum positively correlated with improvement in motor measures between baseline and follow-up., Discussion: To our knowledge, this study is original because is a longitudinal study combining VBM and DTI during the first 4 months after stroke in a series of patients selected on pure motor deficit. Our data would suggest that good recovery relies on spared CST fibers, probably from the premotor cortex, rather than on the aMF in this group with mild motor deficit. The present study suggests that VBM and FA CST could provide reliable biomarkers of post-stroke atrophy, reorganization, plasticity and recovery., Gov Identifier: NCT01862172, registered May 24, 2013., (© 2024. The Author(s).)

Deep intracerebral hemorrhage (ICH) exerts a direct force on corticospinal tracts (CST) causing shape deformation. Using serial MRI, Generalized Procrustes Analysis (GPA), and Principal Components Analysis (PCA), we temporally evaluated the change in CST shape. Thirty-five deep ICH patients with ipsilesional-CST deformation were serially imaged on a 3T-MRI with a median imaging time of day-2 and 84 of onset. Anatomical and diffusion tensor images (DTI) were acquired. Using DTI color-coded maps, 15 landmarks were drawn on each CST and the centroids were computed in 3 dimensions. The contralesional-CST landmarks were used as a reference. The GPA outlined the shape coordinates and we superimposed the ipsilesional-CST shape at the two-time points. A multivariate PCA was applied to identify eigenvectors associated with the highest percentile of change. The first three principal components representing CST deformation along the left-right (PC1), anterior-posterior (PC2), and superior-inferior (PC3) respectively were responsible for 57.9% of shape variance. The PC1 (36.1%, p < 0.0001) and PC3 (9.58%, p < 0.01) showed a significant deformation between the two-time points. Compared to the contralesional-CST, the ipsilesional PC scores were significantly (p < 0.0001) different only at the first-timepoint. A significant positive association between the ipsilesional-CST deformation and hematoma volume was observed. We present a novel method to quantify CST deformation caused by ICH. Deformation most often occurs in left-right axis (PC1) and superior-inferior (PC3) directions. As compared to the reference, the significant temporal difference at the first time point suggests CST restoration over time., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Introduction: Ipsilateral hemiparesis (IH) can be defined as a paradoxical dysfunction of the first motor neuron involving the extremities on the opposite side to that expected, given the location of the triggering intracranial pathology. Compression of the corticospinal tract (CSt) along its course through the contralateral cerebral peduncle against the free edge of the tentorium, known as the Kernohan-Woltman notch phenomenon (KWNP), represents the main cause of IH., Methods: This retrospective study analyses a series of 12 patients diagnosed with IH secondary to KWNP treated at our institution, including a descriptive study of epidemiological, clinical, radiological, neurophysiological, and prognostic variables., Results: In 75% of the cases, symptoms had an acute or subacute onset. Initial imaging studies showed signs of significant mass effect in half of the patients, whereas magnetic resonance imaging (MRI) identified a structural lesion in the contralateral cerebral peduncle in two thirds of them. Impairment of the motor evoked potentials (MEP) was verified in 4 patients. During follow-up 7 patients experienced improvement in motor activity, and near half of the cases were classified in the first three categories of the modified Rankin scale., Conclusions: In contrast to prior historical series, most of our patients developed a KWNP secondary to a traumatic mechanism. MRI represents the optimal method to identify both the classic cerebral peduncle notch and the underlying structural lesion of the CSt. The use of MEP can help to establish the diagnosis, especially in those cases lacking definite radiological findings., (Copyright © 2022 Sociedad Española de Neurología. Published by Elsevier España, S.L.U. All rights reserved.)

Background and Objectives: Childhood cerebral adrenoleukodystrophy (C-ALD) is a severe inflammatory demyelinating disease that must be treated at an early stage to prevent permanent brain injury and neurocognitive decline. In standard clinical practice, C-ALD lesions are detected and characterized by a neuroradiologist reviewing anatomical MRI scans. We aimed to assess whether diffusion tensor imaging (DTI) is sensitive to the presence and severity of C-ALD lesions and to investigate associations with neurocognitive outcomes after hematopoietic cell therapy (HCT)., Methods: In this retrospective cohort study, we analyzed high-resolution anatomical MRI, DTI, and neurocognitive assessments from boys with C-ALD undergoing HCT at the University of Minnesota between 2011 and 2021. Longitudinal DTI data were compared with an age-matched group of boys with ALD and no lesion (NL-ALD). DTI metrics were obtained for atlas-based regions of interest (ROIs) within 3 subdivisions of the corpus callosum (CC), corticospinal tract (CST), and total white matter (WM). Between-group baseline and slope differences in fractional anisotropy (FA) and axial (AD), radial (RD), and mean (MD) diffusivities were compared using analysis of covariance accounting for age, MRI severity (Loes score), and lesion location., Results: Among patients with NL-ALD (n = 14), stable or increasing FA, stable AD, and stable or decreasing RD and MD were generally observed during the 1-year study period across all ROIs. In comparison, patients with mild posterior lesions (Loes 1-2; n = 13) demonstrated lower baseline FA in the CC splenium (C-ALD 0.50 ± 0.08 vs NL-ALD 0.58 ± 0.04; p BH = 0.022 adjusted Benjamini-Hochberg p -value), lower baseline AD across ROIs (e.g., C-ALD 1.34 ± 0.03 ×10 -9 m 2 /s in total WM vs NL-ALD 1.38 ± 0.04 ×10 -9 m 2 /s; p BH = 0.005), lower baseline RD in CC body and CST, and lower baseline MD across ROIs except CC splenium. Longitudinal slopes in CC splenium showed high sensitivity and specificity in differentiating early C-ALD from NL-ALD. Among all patients with C-ALD (n = 38), baseline Loes scores and DTI metrics were associated with post-HCT neurocognitive functions, including processing speed (e.g., FA WM Spearman correlation coefficient R = 0.64) and visual-motor integration (e.g., FA WM R = 0.71)., Discussion: DTI was sensitive to lesion presence and severity as well as clinical neurocognitive effects of C-ALD. DTI metrics quantify C-ALD even at an early stage.

Background Radially sampled averaged magnetization inversion-recovery acquisition (rAMIRA) imaging shows hyperintensity in the lateral corticospinal tract (CST) in patients with motor neuron diseases. Purpose To systematically determine the accuracy of the lateral corticospinal tract sign for detecting patients with amyotrophic lateral sclerosis (ALS) at rAMIRA MRI. Materials and Methods This study included prospectively acquired data from participants in ALS and other motor neuron disease imaging studies at the University Hospital Basel, Switzerland. All participants underwent 3-T axial two-dimensional rAMIRA imaging at four cervical intervertebral disk levels. The lateral CST sign was defined as spinal cord white matter hyperintensity dorsolateral to the anterior horns, with higher signal intensity than in the dorsal columns on axial rAMIRA images. Marker accuracy was assessed in a study data set and in an independent validation data set. Postmortem rAMIRA imaging and histopathologic analysis were performed in one participant who died during the study. Results Participants with ALS (study data set: 38 participants [mean age, 61 years; IQR, 15 years], 22 male participants; validation data set: 10 participants [mean age, 61 years; IQR, 21 years], seven male participants), post-polio syndrome (study data set: 25 participants [mean age, 68 years; IQR, 8 years], 12 male participants), spinal muscular atrophy (study data set: 10 participants [mean age, 43 years; IQR, 14 years], eight male participants; validation data set: five participants [mean age, 38 years; IQR, 19 years], two male participants), and healthy control participants (study data set: 60 participants [mean age, 57 years; IQR, 20 years], 36 male participants; validation data set: 10 participants [mean age, 44 years; IQR, 17 years], seven male participants) were included. The sensitivity and specificity of rAMIRA for ALS were 60% (23 of 38) and 97% (91 of 94) in the study data set and 100% (10 of 10) and 93% (14 of 15) in the validation data set, respectively. Histopathologic analysis showed distinct loss of myelinated axons in the localization of the hyperintensities observed at rAMIRA imaging performed in situ and after organ extraction. Conclusion The recently defined marker at rAMIRA MRI may be a promising tool for assessing upper motor neuron degeneration in the lateral CST in patients with ALS. Clinical trials registration no. NCT03561623, NCT05764434, NCT06137612 © RSNA, 2024 Supplemental material is available for this article.

Objective: The corticospinal tract (CST) is considered the most important motor output pathway comprising fibers from the primary motor cortex (M1) and various premotor areas. Damage to its descending fibers after stroke commonly leads to motor impairment. While premotor areas are thought to critically support motor recovery after stroke, the functional role of their corticospinal output for different aspects of post-stroke motor control remains poorly understood., Methods: We assessed the differential role of CST fibers originating from premotor areas and M1 in the control of basal (single-joint muscle synergies and strength) and complex motor control (involving inter-joint coordination and visuomotor integration) using a novel diffusion imaging approach in chronic stroke patients., Results: While M1 sub-tract anisotropy was positively correlated with basal and complex motor skills, anisotropy of PMd, PMv, and SMA sub-tracts was exclusively associated with complex motor tasks. Interestingly, patients featuring persistent motor deficits showed an additional positive association between premotor sub-tract integrity and basal motor control., Interpretation: While descending M1 output seems to be a prerequisite for any form of upper limb movements, complex motor skills critically depend on output from premotor areas after stroke. The additional involvement of premotor tracts in basal motor control in patients with persistent deficits emphasizes their compensatory capacity in post-stroke motor control. In summary, our findings highlight the pivotal role of descending corticospinal output from premotor areas for motor control after stroke, which thus serve as prime candidates for future interventions to amplify motor recovery., (© 2024 The Author(s). Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Study Objectives: The aim of this study was to investigate the relationship between sleep stages and neural microstructure - measured using diffusion tensor imaging - of the posterior limb of the internal capsule and corticospinal tract in preterm infants., Methods: A retrospective cohort of 50 preterm infants born between 24 + 4 and 29 + 3 weeks gestational age was included in the study. Sleep stages were continuously measured for 5-7 consecutive days between 29 + 0 and 31 + 6 weeks postmenstrual age using an in-house-developed, and recently published, automated sleep staging algorithm based on routinely measured heart rate and respiratory rate. Additionally, a diffusion tensor imaging scan was conducted at term equivalent age as part of standard care. Region of interest analysis of the posterior limb of the internal capsule was performed, and tractography was used to analyze the corticospinal tract. The association between sleep and white matter microstructure of the posterior limb of the internal capsule and corticospinal tract was examined using a multiple linear regression model, adjusted for potential confounders., Results: The results of the analyses revealed an interaction effect between sleep stage and days of invasive ventilation on the fractional anisotropy of the left and right posterior limb of the internal capsule (β = 0.04, FDR-adjusted p = 0.001 and β = 0.04, FDR-adjusted p = 0.02, respectively). Furthermore, an interaction effect between sleep stage and days of invasive ventilation was observed for the radial diffusivity of the mean of the left and right PLIC (β = -4.1e-05, FDR-adjusted p = 0.04)., Conclusions: Previous research has shown that, in very preterm infants, invasive ventilation has a negative effect on white matter tract maturation throughout the brain. A positive association between active sleep and white matter microstructure of the posterior limb of the internal capsule, may indicate a protective role of sleep in this vulnerable population., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

This study aims to explore the link between Apo-E, brain white matter, and suicide in patients with major depressive disorder (MDD) to investigate the potential neuroimmune mechanisms of Apo-E that may lead to suicide. Thirty-nine patients with MDD (22 patients with suicidality) and 57 age, gender, and education-matched healthy controls participated in this study, provided plasma Apo-E samples, and underwent diffusion tensor imaging scans. Plasma Apo-E levels and white matter microstructure were analyzed among the MDD with suicidality, MDD without suicidality, and HC groups using analysis of variance with post hoc Bonferroni correction and tract-based spatial statistics (TBSS) with threshold-free cluster enhancement correction. Mediation analysis investigated the relationship between Apo-E, brain white matter, and suicidality in MDD. The MDD with suicidality subgroup had higher depressive and suicide scores, longer disease course, and lower plasma Apo-E levels than MDD without suicidality. TBSS revealed that the MDD non-suicide subgroup showed significantly increased mean diffusivity in the left corticospinal tract and body of the left corpus callosum, as well as increased axial diffusivity in the left anterior corona radiata and the right posterior thalamic radiation compared to the suicidal MDD group. The main finding was that the increased MD of the left corticospinal tract contributed to the elevated suicide score, with Apo-E mediating the effect. Preliminary result that Apo-E's mediating role between the left corticospinal tract and the suicide factor suggests the neuroimmune mechanism of suicide in MDD. The study was registered on ClinicalTrials.gov (NCT03790085)., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany.)

Studies suggest that amyotrophic lateral sclerosis (ALS) compromises the integrity of white matter fiber tracts, primarily affecting motor fibers. However, it remains uncertain whether the integrity of these fibers influences the risk of ALS. We performed bidirectional two-sample Mendelian randomization (MR) and multivariable MR analyses to evaluate the associative relationships between the integrity of fiber tracts [including the corticospinal tract (CST) and corpus callosum (CC)] and the risk of ALS. Genetic instrumental variables for specific fiber tracts were obtained from published genome-wide association studies (GWASs), including 33,292 European individuals from five diffusion magnetic resonance imaging (dMRI) datasets. Summary-level GWAS data for ALS were derived from 27,205 ALS patients and 110,881 controls. The MR results suggested that an increase in the first principal component (PC1) of fractional anisotropy (FA) in the genu of the CC (GCC) was correlated with an increased risk of ALS (P FDR  = 0.001, odds ratio = 1.363, 95% confidence interval 1.178-1.577). Although other neuroimaging phenotypes [mean diffusivity in the CST, radial diffusivity (RD) in the CST, FA in the GCC, PC1 in the body of the CC (BCC), PC1 in the CST, and RD in the GCC] did not pass correction, they were also considered to have suggestive associations with the risk of ALS. No evidence revealed that ALS caused changes in the integrity of fiber tracts. In summary, the results of this study provide genetic support for the potential association between the integrity of specific fiber tracts and the risk of ALS. Greater fiber integrity in the GCC and BCC may be a risk factor for ALS, while greater fiber integrity in the CST may have a protective effect on ALS. This study provides insights into ALS development., (© 2024. The Author(s).)

Background: Non-invasive brain mapping using navigated transcranial magnetic stimulation (nTMS) is a valuable tool prior to resection of malignant brain tumors. With nTMS motor mapping, it is additionally possible to analyze the function of the motor system and to evaluate tumor-induced neuroplasticity. Distinct changes in motor cortex excitability induced by certain malignant brain tumors are a focal point of research., Methods: A retrospective single-center study was conducted involving patients with malignant brain tumors. Clinical data, resting motor threshold (rMT), and nTMS-based tractography were evaluated. The interhemispheric rMT-ratio (rMTTumor/rMTControl) was calculated for each extremity and considered pathological if it was >110% or <90%. Distances between the corticospinal tract and the tumor (lesion-to-tract-distance - LTD) were measured., Results: 49 patients were evaluated. 16 patients (32.7%) had a preoperative motor deficit. The cohort comprised 22 glioblastomas (44.9%), 5 gliomas of Classification of Tumors of the Central Nervous System (CNS WHO) grade 3 (10.2%), 6 gliomas of CNS WHO grade 2 (12.2%) and 16 cerebral metastases (32.7%). 26 (53.1%) had a pathological rMT-ratio for the upper extremity and 35 (71.4%) for the lower extremity. All patients with tumor-induced motor deficits had pathological interhemispheric rMT-ratios, and presence of tumor-induced motor deficits was associated with infiltration of the tumor to the nTMS-positive cortex ( p = 0.04) and shorter LTDs (all p < 0.021). Pathological interhemispheric rMT-ratio for the upper extremity was associated with cerebral metastases, but not with gliomas ( p = 0.002)., Conclusions: Our study underlines the diagnostic potential of nTMS motor mapping to go beyond surgical risk stratification. Pathological alterations in motor cortex excitability can be measured with nTMS mapping. Pathological cortical excitability was more frequent in cerebral metastases than in gliomas., Competing Interests: The authors declare no conflict of interest., (© 2024 The Author(s). Published by IMR Press.)

Study Design: prospective case series of Yucatan miniature pig spinal cord contusion injury model with comparison to human cases of spinal cord injury (SCI)., Objectives: to describe magnetic resonance imaging (MRI) measures of spinal cord lesion severity along with estimates of lateral corticospinal tracts spared neural tissue in both a less severe and more severe contusion SCI model, as well as to describe their corresponding behavioral outcome changes., Setting: University laboratory setting., Methods: Following a more severe and less severe SCI, each pig underwent spinal cord MRI to measure lesion characteristics, along with locomotor and urodynamics outcomes testing., Results: In the pig with more severe SCI, locomotor and urodynamic outcomes were poor, and both the spinal cord lesion volume and damage estimates to the lateral corticospinal tracts were large. Conversely, in the pig with less severe SCI, locomotor and urodynamic outcomes were favorable, with the spinal cord lesion volume and damage estimates to the lateral corticospinal tracts being less pronounced. For two human cases matched on estimates of damage to the lateral corticospinal tract regions, the clinical presentations were similar to the pig outcomes, with more limited mobility and more limited bladder functional independence in the more severe case., Conclusions: Our initial findings contribute valuable insights to the emergent field of MRI-based evaluation of spinal cord lesions in pig models, offering a promising avenue for understanding and potentially improving outcomes in spinal cord injuries., (© 2024. The Author(s), under exclusive licence to International Spinal Cord Society.)

Background: Upper limb motor impairment commonly occurs after stroke, impairing quality of life. Brain network reorganization likely differs between subgroups with differing impairment severity. This study explored differences in functional connectivity (FC) and corticospinal tract (CST) integrity between patients with mild/moderate versus severe hemiplegia poststroke to clarify the neural correlates underlying motor deficits., Method: Sixty chronic stroke patients with upper limb motor impairment were categorized into mild/moderate and severe groups based on Fugl-Meyer scores. Resting-state FC was assessed using functional near-infrared spectroscopy (fNIRS) to compare connectivity patterns between groups across motor regions. CST integrity was evaluated by inducing motor evoked potentials (MEP) via transcranial magnetic stimulation., Results: Compared to the mild/moderate group, the severe group exhibited heightened premotor cortex-primary motor cortex (PMC-M1) connectivity (t = 4.56, p < 0.01). Absence of MEP was also more frequent in the severe group (χ 2  = 12.31, p = 0.01). Bayesian models effectively distinguished subgroups and identified the PMC-M1 connection as highly contributory (accuracy = 91.30%, area under the receiver operating characteristic curve [AUC] = 0.86)., Conclusion: Distinct patterns of connectivity and corticospinal integrity exist between stroke subgroups with differing impairments. Strengthened connectivity potentially indicates recruitment of additional motor resources to compensate for damage. These findings elucidate the neural correlates underlying motor deficits poststroke and could guide personalized, network-based therapies targeting predictive biomarkers to improve rehabilitation outcomes., (© 2024 The Author(s). CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Tractography has become a widely available tool for the planning of neurosurgical operations as well as for neuroscientific research. The absence of patient interaction makes it easily applicable. However, it leaves uncertainty about the functional relevance of the identified bundles. We retrospectively analyzed the correlation of white matter markers with their clinical function in 24 right-handed patients who underwent first surgery for high-grade glioma. Morphological affection of the corticospinal tract (CST) and grade of paresis were assessed before surgery. Tractography was performed manually with MRTrix3 and automatically with TractSeg. Median and mean fractional anisotropy (FA) from manual tractography showed a significant correlation with CST affection (p = 0.008) and paresis (p = 0.015, p = 0.026). CST affection correlated further most with energy, and surface-volume ratio (p = 0.014) from radiomic analysis. Paresis correlated most with maximum 2D column diameter (p = 0.005), minor axis length (p = 0.006), and kurtosis (p = 0.008) from radiomic analysis. Streamline count yielded no significant correlations. In conclusion, mean or median FA can be used for the assessment of CST integrity in high-grade glioma. Also, several radiomic parameters are suited to describe tract integrity and may be used to quantitatively analyze white matter in the future., (© 2024. The Author(s).)

Navigated repetitive transmagnetic stimulation is a non-invasive and safe brain activity modulation technique. When combined with the classical rehabilitation process in stroke patients it has the potential to enhance the overall neurologic recovery. We present a case of a peri-operative stroke, treated with ultra-early low frequency navigated repetitive transmagnetic stimulation over the contralesional hemisphere. The patient received low frequency navigated repetitive transmagnetic stimulation within 12 hours of stroke onset for seven consecutive days and a significant improvement in his right sided weakness was noticed and he was discharge with normal power. This was accompanied by an increase in the number of positive responses evoked by navigated repetitive transmagnetic stimulation and a decrease of the resting motor thresholds at a cortical level. Subcortically, a decrease in the radial, axial, and mean diffusivity were recorded in the ipsilateral corticospinal tract and an increase in fractional anisotropy, axial diffusivity, and mean diffusivity was observed in the interhemispheric fibers of the corpus callosum responsible for the interhemispheric connectivity between motor areas. Our case demonstrates clearly that ultra-early low frequency navigated repetitive transmagnetic stimulation applied to the contralateral motor cortex can lead to significant clinical motor improvement in patients with subcortical stroke., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.)

Introduction: Prodromal Parkinson's disease (PD) carriers of dual leucine-rich repeat kinase 2 (LRRK2) and glucosylceramidase β (GBA) variants are rare, and their biomarkers are less well developed., Objective: This study aimed to investigate the biomarkers for diagnosing the prodromal phase of LRRK2-GBA-PD (LRRK2-GBA-prodromal)., Methods: We assessed the clinical and whole-brain white matter microstructural characteristics of 54 prodromal PD carriers of dual LRRK2 (100% M239T) and GBA (95% N409S) variants, along with 76 healthy controls (HCs) from the Parkinson's Progression Markers Initiative (PPMI) cohort., Results: By analyzing the four values of 100 nodes on 20 fiber bundles, totaling 8000 data points, we identified the smallest p value in the fractional anisotropy (FA) value of the 38th segment of left corticospinal tract (L-CST) with differences between LRRK2-GBA-prodromal and HCs (p = 8.94 × 10 -9 ). The FA value of the 38th node of the L-CST was significantly lower in LRRK2-GBA-prodromal (FA value, 0.65) compared with HCs (FA value, 0.71). The receiver-operating characteristic curve showed a cut-off value of 0.218 for the FA value of L-CST, providing sufficient sensitivity (79.2%) and specificity (72.2%) to distinguish double mutation prodromal PD from the healthy population., Conclusion: L-CST, especially the 38th node, may potentially serve as a biomarker for distinguishing individuals with double mutation prodromal PD from the healthy population., (© 2024 The Authors. CNS Neuroscience & Therapeutics published by John Wiley & Sons Ltd.)

Objective: Establish the evolution of the connectome before and after resection of motor area glioma using a comparison of connectome maps and high-definition differential tractography (DifT)., Methods: DifT was done using normalized quantitative anisotropy (NQA) with DSI Studio. The quantitative analysis involved obtaining mean NQA and fractional anisotropy (FA) values for the disrupted pathways tracing the corticospinal tract (CST), and white fiber network changes over time., Results: We described the baseline tractography, DifT, and white matter network changes from two patients who underwent resection of an oligodendroglioma (Case 1) and an IDH mutant astrocytoma, grade 4 (Case 2)., Case 1: There was a slight decrease in the diffusion signal of the compromised CST in the immediate postop. The NQA and FA values increased at the 1-year follow-up (0.18 vs. 0.32 and 0.35 vs. 0.44, respectively)., Case 2: There was an important decrease in the immediate postop, followed by an increase in the follow-up. In the 1-year follow-up, the patient presented with radiation necrosis and tumor recurrence, increasing NQA from 0.18 in the preop to 0.29. Fiber network analysis: whole-brain connectome comparison demonstrated no significant changes in the immediate postop. However, in the 1-year follow up there was a notorious reorganization of the fibers in both cases, showing the decreased density of connections., Conclusions: Connectome studies and DifT constitute new potential tools to predict early reorganization changes in a patient's networks, showing the brain plasticity capacity, and helping to establish timelines for the progression of the tumor and treatment-induced changes., Competing Interests: Declaration of Competing Interest The authors have no conflict of interest to report., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Focal structural damage to white matter tracts can result in functional deficits in stroke patients. Traditional voxel-based lesion-symptom mapping is commonly used to localize brain structures linked to neurological deficits. Emerging evidence suggests that the impact of structural focal damage may extend beyond immediate lesion sites. In this study, we present a disconnectome mapping approach based on support vector regression (SVR) to identify brain structures and white matter pathways associated with functional deficits in stroke patients. For clinical validation, we utilized imaging data from 340 stroke patients exhibiting motor deficits. A disconnectome map was initially derived from lesions for each patient. Bootstrap sampling was then employed to balance the sample size between a minority group of patients exhibiting right or left motor deficits and those without deficits. Subsequently, SVR analysis was used to identify voxels associated with motor deficits (p < .005). Our disconnectome-based analysis significantly outperformed alternative lesion-symptom approaches in identifying major white matter pathways within the corticospinal tracts associated with upper-lower limb motor deficits. Bootstrapping significantly increased the sensitivity (80%-87%) for identifying patients with motor deficits, with a minimum lesion size of 32 and 235 mm 3 for the right and left motor deficit, respectively. Overall, the lesion-based methods achieved lower sensitivities compared with those based on disconnection maps. The primary contribution of our approach lies in introducing a bootstrapped disconnectome-based mapping approach to identify lesion-derived white matter disconnections associated with functional deficits, particularly efficient in handling imbalanced data., (© 2024 The Authors. European Journal of Neuroscience published by Federation of European Neuroscience Societies and John Wiley & Sons Ltd.)

Purpose: Advanced MR fiber tracking imaging reflects fiber bundle invasion by glioblastoma, particularly of the corticospinal tract (CST), which is more susceptible as the largest downstream fiber tracts. We aimed to investigate whether CST features can predict the overall survival of glioblastoma., Methods: In this prospective secondary analysis, 40 participants (mean age, 58 years; 16 male) pathologically diagnosed with glioblastoma were enrolled. Diffusion spectrum MRI was used for CST reconstruction. Fifty morphological and diffusion indicators (DTI, DKI, NODDI, MAP and Q-space) were used to characterize the CST. Optimal parameters capturing fiber bundle damage were obtained through various grouping methods. Eventually, the correlation with overall survival was determined by the hazard ratios (HRs) from various Cox proportional hazard model combinations., Results: Only intracellular volume fraction (ICVF) and non-Gaussianity (NG) values on the affected tumor level were significant in all four groups or stratified comparisons (all P < .05). During the median follow-up 698 days, only the ICVF on the affected tumor level was independently associated with overall survival, even after adjusting for all classic prognostic factors (HR [95 % CI]: 0.611 [0.403, 0.927], P = .021). Moreover, stratification by the ICVF on the affected tumor level successfully predicted risk (P < .01) and improved the C-index of the multivariate model (from 0.695 to 0.736)., Conclusions: This study demonstrates a relationship between NODDI-derived CST features, ICVF on the affected tumor level, and overall survival in glioblastoma. Independent of classical prognostic factors for glioblastoma, a lower ICVF on the affected tumor level might predict a lower overall survival., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Rationale and Objectives: Stroke patients commonly face challenges during magnetic resonance imaging (MRI) examinations due to involuntary movements. This study aims to overcome these challenges by utilizing multiple overlapping-echo detachment (MOLED) quantitative technology. Through this technology, we also seek to detect microstructural changes of the normal-appearing corticospinal tract (NA-CST) in subacute-chronic stroke patients., Materials and Methods: 79 patients underwent 3.0 T MRI scans, including routine scans and MOLED technique. A deep learning network was utilized for image reconstruction, and the accuracy, reliability, and resistance to motion of the MOLED technique were validated on phantoms and volunteers. Subsequently, we assessed motor dysfunction severity, ischemic lesion volume, T 2 values of the bilateral NA-CST, and the T 2 ratio (rT 2 ) between the ipsilesional and contralesional NA-CST in patients., Results: The MOLED technique showed high accuracy (P < 0.001) and excellent repeatability, with a mean coefficient of variation (CoV) of 1.11%. It provided reliable quantitative results even under head movement, with a mean difference (Mean diff )= 0.28% and a standard deviation difference (SD diff )= 1.34%. Additionally, the T 2 value of the ipsilesional NA-CST was significantly higher than contralesional side (P < 0.001), and a positive correlation was observed between rT 2 and the severity of motor dysfunction (r s =0.575, P < 0.001). Furthermore, rT 2 successfully predicted post-stroke motor impairment, with an area under the curve (AUC) was 0.883., Conclusion: The MOLED technique offers significant advantages for quantitatively imaging stroke patients with involuntary movements. Additionally, T 2 mapping from MOLED can detect microstructural changes in the NA-CST, potentially aiding in monitoring stroke-induced motor impairment., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Association of University Radiologists. Published by Elsevier Inc. All rights reserved.)

Background: Corticospinal tract (CST) is the principal motor pathway; we aim to explore the structural plasticity mechanism in CST during stroke rehabilitation., Methods: A total of 25 patients underwent diffusion tensor imaging before rehabilitation (T1), 1-month post-rehabilitation (T2), 2 months post-rehabilitation (T3), and 1-year post-discharge (T4). The CST was segmented, and fractional anisotropy (FA), axial diffusion (AD), mean diffusivity (MD), and radial diffusivity (RD) were determined using automated fiber quantification tractography. Baseline level of laterality index (LI) and motor function for correlation analysis., Results: The FA values of all segments in the ipsilesional CST (IL -CST ) were lower compared with normal CST. Repeated measures analysis of variance showed time-related effects on FA, AD, and MD of the IL -CST , and there were similar dynamic trends in these 3 parameters. At T1, FA, AD, and MD values of the mid-upper segments of IL -CST (around the core lesions) were the lowest; at T2 and T3, values for the mid-lower segments were lower than those at T1, while the values for the mid-upper segments gradually increased; at T4, the values for almost entire IL -CST were higher than before. The highest LI was observed at T2, with a predominance in contralesional CST. The LIs for the FA and AD at T1 were positively correlated with the change rate of motor function., Conclusions: IL -CST showed aggravation followed by improvement from around the lesion to the distal end. Balance of interhemispheric CST may be closely related to motor function, and LIs for FA and AD may have predictive value for mild-to-moderate stroke rehabilitation. Clinical Trial Registration . URL: http://www.chictr.org.cn; Unique Identifier: ChiCTR1800019474., Competing Interests: Declaration of Conflicting InterestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background and Objectives: Motor outcomes after stroke relate to corticospinal tract (CST) damage. The brain leverages surviving neural pathways to compensate for CST damage and mediate motor recovery. Thus, concurrent age-related damage from white matter hyperintensities (WMHs) might affect neurologic capacity for recovery after CST injury. The role of WMHs in post-stroke motor outcomes is unclear. In this study, we evaluated whether WMHs modulate the relationship between CST damage and post-stroke motor outcomes., Methods: We used data from the multisite ENIGMA Stroke Recovery Working Group with T1 and T2/fluid-attenuated inversion recovery imaging. CST damage was indexed with weighted CST lesion load (CST-LL). WMH volumes were extracted with Freesurfer's SAMSEG. Mixed-effects beta-regression models were fit to test the impact of CST-LL, WMH volume, and their interaction on motor impairment, controlling for age, days after stroke, and stroke volume., Results: A total of 223 individuals were included. WMH volume related to motor impairment above and beyond CST-LL (β = 0.178, 95% CI 0.025-0.331, p = 0.022). Relationships varied by WMH severity (mild vs moderate-severe). In individuals with mild WMHs, motor impairment related to CST-LL (β = 0.888, 95% CI 0.604-1.172, p < 0.001) with a CST-LL × WMH interaction (β = -0.211, 95% CI -0.340 to -0.026, p = 0.026). In individuals with moderate-severe WMHs, motor impairment related to WMH volume (β = 0.299, 95% CI 0.008-0.590, p = 0.044), but did not significantly relate to CST-LL or a CST-LL × WMH interaction., Discussion: WMHs relate to motor outcomes after stroke and modify relationships between motor impairment and CST damage. WMH-related damage may be under-recognized in stroke research as a factor contributing to variability in motor outcomes. Our findings emphasize the importance of brain structural reserve in motor outcomes after brain injury.

The frequency of corticospinal tract (CST) T2/FLAIR hyperintensity in disorders with neuroglial antibodies is unclear. Herein, we retrospectively reviewed brain MRIs of 101 LGI1-antibody encephalitis patients, and observed CST hyperintensity in 30/101 (30%). It was mostly bilateral (93%), not associated with upper motor neuron signs/symptoms (7%), and frequently decreased over time (39%). In a systematic review including patients with other neuroglial antibodies, CST hyperintensity was reported in 110 with neuromyelitis optica (94%), myelin oligodendrocyte glycoprotein-associated disease (2%), Ma2-antibody (3%) and GAD65-antibody paraneoplastic neurological syndrome (1%). CST hyperintensity is not an infrequent finding in LGI1-Ab encephalitis and other disorders with neuroglial antibodies., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier B.V. All rights reserved.)

This study aimed to assess the effects of human urinary kallidinogenase (HUK) on motor function outcome and corticospinal tract recovery in patients with acute ischemic stroke (AIS). This study was a randomized, controlled, single-blinded trial. Eighty AIS patients were split into two groups: the HUK and control groups. The HUK group was administered HUK and standard treatment, while the control group received standard treatment only. At admission and discharge, the National Institutes of Health Stroke Scale (NIHSS), Barthel Index (BI) and muscle strength were scored. The primary endpoint was the short-term outcomes of AIS patients under different treatments. The secondary endpoint was the degree of corticospinal tract fiber damage under different treatments. There was a significant improvement in the NIHSS Scale, BI and muscle strength scores in the HUK group compared with controls (Mann-Whitney U test; P  < 0.05). Diffusion tensor tractography classification and intracranial arterial stenosis were independent predictors of short-term recovery by linear regression analysis. The changes in fractional anisotropy (FA) and apparent diffusion coefficient (ADC) decline rate were significantly smaller in the HUK group than in the control group ( P <  0.05). Vascular endothelial growth factor (VEGF) increased significantly after HUK treatment ( P  < 0.05), and the VEGF change was negatively correlated with changes in ADC. HUK is beneficial for the outcome in AIS patients especially in motor function recovery. It may have protective effects on the corticospinal tract which is reflected by the reduction in the FA and ADC decline rates and increased VEGF expression. The study was registered on ClinicalTrials.gov (unique identifier: NCT04102956)., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Gliomas adjacent to the corticospinal tract (CST) should be carefully resected to preserve motor function while achieving maximal surgical resection. Modern high-field intraoperative magnetic resonance imaging (iMRI) enables precise visualization of the residual tumor and intraoperative tractography. We prospectively evaluated the extent of resection and distance between the tumor resection cavity and CST using 3-T iMRI combined with motor evoked potentials (MEP) in glioma surgery., Methods: Participants comprised patients who underwent surgery for solitary supratentorial glioma located within 10 mm of the CST. All cases underwent surgery using neuronavigation with overlaid CST under MEP monitoring. The correlation between distance from CST and transcortical MEP amplitude was calculated using Spearman rank correlation., Results: Among the 63 patients who underwent surgery, 27 patients were enrolled in the study. Gross total resections were achieved in 26 of the 27 cases. Volumetric analysis showed the extent of resection was 98.6%. Motor function was stable or improved in 24 patients (Stable/Improved group) and deteriorated in 3 patients (Deteriorated group). All patients in the Deteriorated group showed motor deficit before surgery. Mean intraoperative minimal distance was significantly longer in the Stable/Improved group (7.3 mm) than in the Deteriorated group (1.1 mm; P < 0.05). MEP amplitude correlated with minimal distance between the resection cavity and CST (R = 0.64)., Conclusions: Resection of gliomas adjacent to CST with a navigation system using 3-T iMRI could result in an ultimate EOR >98%. The combination of intraoperative tractography and MEP contributes to maximal removal of motor-eloquent gliomas., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Purpose: This study aimed to investigate the diagnostic performance of diffusion kurtosis imaging (DKI) and diffusion tensor imaging (DTI) in identifying aberrations in the corticospinal tract (CST), whilst elucidating the relationship between abnormalities of CST and patients' motor function., Methods: Altogether 21 patients with WHO grade II or grade IV glioma were enrolled and divided into Group 1 and Group 2, according to the presence or absence of preoperative paralysis. DKI and DTI metrics were generated and projected onto the CST. Histograms of the CST along x, y, and z axes were developed based on DKI and DTI metrics, and compared subsequently to determine regions of aberrations on the fibers. The receiver operating characteristic curve was performed to investigate the diagnostic efficacy of DKI and DTI metrics., Results: In Group 1, a significantly lower fractional anisotropy, radial kurtosis and mean kurtosis, and a higher mean diffusivity were found in the ipsilateral CST as compared to the contralateral CST. Significantly higher relative axial diffusivity, relative radial diffusivity, and relative mean diffusivity (rMD) were found in Group 1, as compared to Group 2. The relative volume of ipsilateral CST abnormalities higher than the maximum value of mean kurtosis combined with rMD exhibited the best diagnostic performance in distinguishing dysfunction of CST with an AUC of 0.93., Conclusion: DKI is sensitive in detecting subtle changes of CST distal from the tumor. The combination of DKI and DTI is feasible for evaluating the impairment of the CST., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objectives: Accurate presurgical brain mapping enables preoperative risk assessment and intraoperative guidance. This cross-sectional study investigated whether constrained spherical deconvolution (CSD) methods were more accurate than diffusion tensor imaging (DTI)-based methods for presurgical white matter mapping using intraoperative direct electrical stimulation (DES) as the ground truth., Methods: Five different tractography methods were compared (three DTI-based and two CSD-based) in 22 preoperative neurosurgical patients undergoing surgery with DES mapping. The corticospinal tract (CST, N = 20) and arcuate fasciculus (AF, N = 7) bundles were reconstructed, then minimum distances between tractograms and DES coordinates were compared between tractography methods. Receiver-operating characteristic (ROC) curves were used for both bundles. For the CST, binary agreement, linear modeling, and posthoc testing were used to compare tractography methods while correcting for relative lesion and bundle volumes., Results: Distance measures between 154 positive (functional response, pDES) and negative (no response, nDES) coordinates, and 134 tractograms resulted in 860 data points. Higher agreement was found between pDES coordinates and CSD-based compared to DTI-based tractograms. ROC curves showed overall higher sensitivity at shorter distance cutoffs for CSD (8.5 mm) compared to DTI (14.5 mm). CSD-based CST tractograms showed significantly higher agreement with pDES, which was confirmed by linear modeling and posthoc tests (P FWE  < .05)., Conclusions: CSD-based CST tractograms were more accurate than DTI-based ones when validated using DES-based assessment of motor and sensory function. This demonstrates the potential benefits of structural mapping using CSD in clinical practice., (© 2024 The Authors. Human Brain Mapping published by Wiley Periodicals LLC.)

The pathological hallmarks of amyotrophic lateral sclerosis (ALS) are degeneration of the primary motor cortex grey matter (GM) and corticospinal tract (CST) resulting in upper motor neuron (UMN) dysfunction. Conventional brain magnetic resonance imaging (MRI) shows abnormal CST hyperintensity in some UMN-predominant ALS patients (ALS-CST+) but not in others (ALS-CST-). In addition to the CST differences, we aimed to determine whether GM degeneration differs between ALS-CST+ and ALS-CST- patients by cortical thickness (CT), voxel-based morphometry (VBM) and fractal dimension analyses. We hypothesized that MRI multifractal (MF) measures could differentiate between neurologic controls (n = 14) and UMN-predominant ALS patients as well as between patient subgroups (ALS-CST+, n = 21 vs ALS-CST-, n = 27). No significant differences were observed in CT or GM VBM in any brain regions between patients and controls or between ALS subgroups. MF analyses were performed separately on GM of the whole brain, of frontal, parietal, occipital, and temporal lobes as well as of cerebellum. Estimating MF measures D (Q = 0), D (Q = 1), D (Q = 2), Δf, Δα of frontal lobe GM classified neurologic controls, ALS-CST+ and ALS-CST- groups with 98% accuracy and > 95% in F1, recall, precision and specificity scores. Classification accuracy was only 74% when using whole brain MF measures and < 70% for other brain lobes. We demonstrate that MF analysis can distinguish UMN-predominant ALS subgroups based on GM changes, which the more commonly used quantitative approaches of CT and VBM cannot., Competing Interests: Declaration of competing interest The authors do not report any conflict of interest relevant to the present study. EPP has received clinical trial and research funding from Biogen, Inc., Biohaven Pharmaceuticals, NIH/CDC, and serves as consultant to Amylyx Pharmaceuticals, Avanir Pharmaceuticals, Inc., Biohaven Pharmaceuticals, Cytokinetics, Inc., ITF Pharma, Inc., MT Pharma America, Inc., and Otsuka America, Inc., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Non-invasive brain stimulation techniques such as transcranial magnetic stimulation and transcranial direct current stimulation hold promise for inducing brain plasticity. However, their limited precision may hamper certain applications. In contrast, Transcranial Ultrasound Stimulation (TUS), known for its precision and deep brain targeting capabilities, requires further investigation to establish its efficacy in producing enduring effects for treating neurological and psychiatric disorders., Objective: To investigate the enduring effects of different pulse repetition frequencies (PRF) of TUS on motor corticospinal excitability., Methods: T1-, T2-weighted, and zero echo time magnetic resonance imaging scans were acquired from 21 neurologically healthy participants for neuronavigation, skull reconstruction, and the performance of transcranial ultrasound and thermal modelling. The effects of three different TUS PRFs (10, 100, and 1000 Hz) with a constant duty cycle of 10 % on corticospinal excitability in the primary motor cortex were assessed using TMS-induced motor evoked potentials (MEPs). Each PRF and sham condition was evaluated on separate days, with measurements taken 5-, 30-, and 60-min post-TUS., Results: A significant decrease in MEP amplitude was observed with a PRF of 10 Hz (p = 0.007), which persisted for at least 30 min, and with a PRF of 100 Hz (p = 0.001), lasting over 60 min. However, no significant changes were found for the PRF of 1000 Hz and the sham conditions., Conclusion: This study highlights the significance of PRF selection in TUS and underscores its potential as a non-invasive approach to reduce corticospinal excitability, offering valuable insights for future clinical applications., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Central pontine myelinolysis (CPM) is a rare demyelinating disease that affects the pons and which can cause extreme disabilities such as locked-in syndrome (LIS) in the initial phase. The aim of the study was to describe the evolution over a 12-month period of two patients with CPM causing an initial LIS., Method: We retrospectively report the unexpected clinical outcome of these two patients in relation with the anatomical damages documented by brain MRI, associated with diffusion tensor imaging and reconstruction of corticospinal tracts in tractography. The following clinical parameters systematically assessed at 3, 6, 9, and 12 months: muscle testing on 12 key muscles (Medical Research Council), prehension metrics (box and block test and purdue pegboard), and independence for acts of daily living (functional independence measure)., Results: Both patients showed a progressive recovery beginning between 2 and 3 months after the onset of symptoms, leading to almost complete autonomy at 12 months (FIM > 110), with motor strength greater than 4/5 in all joint segments (MRC > 50/60). On brain MRI with tractography, CST appeared partially preserved at pons level., Interpretation: The possibility of a near-complete functional recovery at 12 months is important to consider given the ethical issues at stake and the discussions about limiting care that may take place initially. It seems to be the consequence of reversible myelin damage combined with partially preserved neurons. Development of collateral pathways or resolution of conduction block may explain this recovery. MRI comprising DTI and tractography could play a key role in the prognosis of motor recovery., (© 2024 The Authors. Annals of Clinical and Translational Neurology published by Wiley Periodicals LLC on behalf of American Neurological Association.)

Motor neuron disease with isolated or predominant lesion of the lower motor neuron at one level of the pyramidal tract is a rare diagnostic finding. In the article, we analyze the case of a patient with asymmetric lesion of the inferior motor neuron at the cervical level: clinical manifestations, results of additional studies and dynamic observation of the patient. Special attention is paid to the MRI picture of changes in the pyramidal tracts in the cervical region, which have been called the «snake eyes» in the literature, and the impact of this finding on the diagnosis and prognosis of the disease.

Objective: The corticospinal tract (CST) reveals progressive microstructural alterations in ALS measurable by DTI. The aim of this study was to evaluate fractional anisotropy (FA) along the CST as a longitudinal marker of disease progression in ALS., Methods: The study cohort consisted of 114 patients with ALS and 110 healthy controls from the second prospective, longitudinal, multicentre study of the Canadian ALS Neuroimaging Consortium (CALSNIC-2). DTI and clinical data from a harmonized protocol across 7 centres were collected. Thirty-nine ALS patients and 61 controls completed baseline and two follow-up visits and were included for longitudinal analyses. Whole brain-based spatial statistics and hypothesis-guided tract-of-interest analyses were performed for cross-sectional and longitudinal analyses., Results: FA was reduced at baseline and longitudinally in the CST, mid-corpus callosum (CC), frontal lobe, and other ALS-related tracts, with alterations most evident in the CST and mid-CC. CST and pontine FA correlated with functional impairment (ALSFRS-R), upper motor neuron function, and clinical disease progression rate. Reduction in FA was largely located in the upper CST; however, the longitudinal decline was greatest in the lower CST. Effect sizes were dependent on region, resulting in study group sizes between 17 and 31 per group over a 9-month interval. Cross-sectional effect sizes were maximal in the upper CST; whereas, longitudinal effect sizes were maximal in mid-callosal tracts., Conclusions: Progressive microstructural alterations in ALS are most prominent in the CST and CC. DTI can provide a biomarker of cerebral degeneration in ALS, with longitudinal changes in white matter demonstrable over a reasonable observation period, with a feasible number of participants, and within a multicentre framework., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Inc.)

An urgent problem in modern neurosurgery is resection of brain tumors adjacent to corticospinal tract (CST) due to high risk of its damage and subsequent disability. The main methods for prevention of intraoperative damage to CST are preoperative MR tractography and intraoperative electrophysiological monitoring. Both methods are used in pediatric neurosurgery. We reviewed the PubMed database since 2000 using the following keywords: «tumors of the hemispheres in children», «corticospinal tract», «MR tractography», «intraoperative electrophysiological monitoring». We present available literature data on preoperative MR tractography and intraoperative electrophysiological monitoring in children with supratentorial tumors near CST. Algorithm of intraoperative electrophysiological monitoring is often missing or insufficiently described. MR tractography is usually presented in case reports. Researchers do not compare the effectiveness of MR tractography and intraoperative electrophysiological monitoring. In case of MR tractography, a limitation is impossible CST reconstruction in children 2-3 years old. This may be due to unformed pyramidal system in these children., Conclusion: Preoperative MR tractography and intraoperative electrophysiological monitoring are valid methods for assessment of CST. Optimal research parameters in children require careful study that will allow objective planning of each stage of preoperative management and increase resection quality for gliomas near CST in children without neurological deterioration.

Multiple lines of research support the dysconnectivity hypothesis of schizophrenia. However, findings on white matter (WM) alterations in patients with schizophrenia are widespread and non-specific. Confounding factors from magnetic resonance image (MRI) processing, clinical diversity, antipsychotic exposure, and substance use may underlie some of the variability. By application of refined methodology and careful sampling, we rectified common confounders investigating WM and symptom correlates in a sample of strictly antipsychotic-naïve first-episode patients with schizophrenia. Eighty-six patients and 112 matched controls underwent diffusion MRI. Using fixel-based analysis (FBA), we extracted fibre-specific measures such as fibre density and fibre-bundle cross-section. Group differences on fixel-wise measures were examined with multivariate general linear modelling. Psychopathology was assessed with the Positive and Negative Syndrome Scale. We separately tested multivariate correlations between fixel-wise measures and predefined psychosis-specific versus anxio-depressive symptoms. Results were corrected for multiple comparisons. Patients displayed reduced fibre density in the body of corpus callosum and in the middle cerebellar peduncle. Fibre density and fibre-bundle cross-section of the corticospinal tract were positively correlated with suspiciousness/persecution, and negatively correlated with delusions. Fibre-bundle cross-section of isthmus of corpus callosum and hallucinatory behaviour were negatively correlated. Fibre density and fibre-bundle cross-section of genu and splenium of corpus callosum were negative correlated with anxio-depressive symptoms. FBA revealed fibre-specific properties of WM abnormalities in patients and differentiated associations between WM and psychosis-specific versus anxio-depressive symptoms. Our findings encourage an itemised approach to investigate the relationship between WM microstructure and clinical symptoms in patients with schizophrenia., (© 2023. The Author(s).)

Background: Gliomas have infiltrative nature and tumor volume has direct prognostic value. Optimal resection limits delineated by high-frequency monopolar stimulation with multipulse short train technique is still a matter of debate for safe surgery without (or with acceptable) neurological deficits. It is also an enigma whether the same cut-off values are valid for high and low grades. We aimed to analyze the value of motor mapping/monitoring findings on postoperative motor outcome in diffuse glioma surgery., Methods: Patients who were operated on due to glioma with intraoperative neuromonitorization at our institution between 2017 and 2021 were analyzed. Demographic information, pre- and post-operative neurological deficit, magnetic resonance images, resection rates, and motor evoked potential (MEP) findings were analyzed., Results: Eighty-seven patients of whom 55 had high-grade tumors were included in the study. Total/near-total resection was achieved in 85%. Subcortical motor threshold (ScMTh) from resection cavity to the corticospinal tract was ≤ 2mA in 17; 3 mA in 14; 4 mA in 6; 5 mA in 7, and ≥5mA in 50 patients. On the 6th month examination, six patients (5 with high-grade tumor) had motor deficits. These patients had changes in MEP that exceeded critical threshold during monitoring. Receiver operating characteristic analysis revealed 2.5 mA ScMTh as the cut-off point for limb paresis after awakening and 6 months for the groups., Conclusions: Subcortical mapping with MEP monitoring helps to achieve safe wider resection. The optimal safe limit for SCMTh was determined as 2.5 mA. Provided that safe threshold values are maintained in MEP, surgeon may force the functional limits by lowering the SCMTh to 1 mA, especially in low-grade gliomas., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.)