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Journal of Digital Imaging Apr 2022We investigate the correlation between diffusion tensor imaging (DTI)-derived metric statistics and motor strength grade of insular glioma patients after optimizing the...
Optimized Tractography Mapping and Quantitative Evaluation of Pyramidal Tracts for Surgical Resection of Insular Gliomas: a Correlative Study with Diffusion Tensor Imaging-Derived Metrics and Patient Motor Strength.
We investigate the correlation between diffusion tensor imaging (DTI)-derived metric statistics and motor strength grade of insular glioma patients after optimizing the pyramidal tract (PT) delineation. Motor strength grades of 45 insular glioma patients were assessed. All the patients underwent structural and diffusion MRI examination before and after surgery. We co-registered pre- and post-op datasets, and a two-tensor unscented Kalman filter (UKF) algorithm was employed to delineate bilateral PTs after DWI pre-processing. The tractography results were voxelized, and their labelmaps were cropped according to the location of frontal and insular parts of the lesion. Both the whole and cropped labelmaps were used as regions of interest to analyze fractional anisotropy (FA) and Trace statistics; hence, their ratios were calculated (lesional side tract/contralateral normal tract). The combination of DWI pre-processing and two-tensor UKF algorithm successfully delineated bilateral PTs of all the patients. It effectively accomplished both full fiber delineation within the edema and an extensive lateral fanning that had a favorable correspondence to the bilateral motor cortices. Before surgery, correlations were found between patients' motor strength grades and ratios of PT volume and FA standard deviation (SD). Nearly 3 months after surgery, correlations were found between motor strength grades and the ratios of metric statistics as follows: whole PT volume, whole mean FA, and FA SD. We substantiated the correlation between DTI-derived metric statistics and motor strength grades of insular glioma patients. Moreover, we posed a workflow for comprehensive pre- and post-op DTI quantitative research of glioma patients.
Topics: Benchmarking; Brain Neoplasms; Diffusion Tensor Imaging; Glioma; Humans; Pyramidal Tracts
PubMed: 35064370
DOI: 10.1007/s10278-021-00578-4 -
AJNR. American Journal of Neuroradiology May 2019Predicting motor outcome following intracerebral hemorrhage is challenging. We tested whether the combination of clinical scores and DTI-based assessment of... (Observational Study)
Observational Study
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.
Topics: Aged; Cerebral Hemorrhage; Diffusion Magnetic Resonance Imaging; Female; Humans; Male; Middle Aged; Motor Disorders; Prognosis; Pyramidal Tracts; Recovery of Function
PubMed: 31000524
DOI: 10.3174/ajnr.A6038 -
Neurology Sep 2010Studies in chronic stroke patients suggest that diffusion tensor imaging (DTI) parameters of the pyramidal tract (PT) relate to residual motor function. We performed a...
BACKGROUND
Studies in chronic stroke patients suggest that diffusion tensor imaging (DTI) parameters of the pyramidal tract (PT) relate to residual motor function. We performed a prospective controlled study to evaluate if the DTI parameters tract volume (TV) and fractional anisotropy (FA) in patients with acute subcortical infarcts are correlated with permanent PT damage and clinical outcome after 6 months.
METHODS
We acquired DTI in 18 stroke patients with subcortical ischemic infarcts either affecting the PT (PT group, n = 12) or not (non-PT group, n = 6) and in 7 age- and risk factor-matched controls at median times of 12 and 180 days. The PT was isolated using tractography and tract volume ratios (R(TV)) and FA ratios (R(FA)) were calculated (affected tract/unaffected tract). Ratios were compared within and between groups at initial and follow-up time points, as well as in tract portions above and below the infarcts, and were correlated to Rivermead Motor Function Test (RMFT) scores.
RESULTS
Mean R(FA) and R(TV) of the PT group were smaller than those of both non-PT and control groups initially and at follow-up (p < 0.01). Tract portions above the infarct had lower R(TV) than below (p < 0.05). There was no significant change in R(FA) and R(TV) over time for the whole tract or tract portions. R(FA) and R(TV) both were highly correlated with initial and follow-up RMFT scores.
CONCLUSIONS
DTI parameters of PT integrity acquired within the first weeks after acute subcortical stroke measure permanent ischemic PT damage and are highly correlated with residual motor function in the acute and chronic stage.
Topics: Adult; Aged; Aged, 80 and over; Anisotropy; Brain Mapping; Cerebral Infarction; Diffusion Tensor Imaging; Female; Humans; Image Processing, Computer-Assisted; Male; Middle Aged; Motor Skills; Prospective Studies; Pyramidal Tracts; Severity of Illness Index; Stroke
PubMed: 20855848
DOI: 10.1212/WNL.0b013e3181f39aa0 -
Journal of Neurotrauma Sep 2020Unlike their peripheral nervous system counterparts, the capacity of central nervous system neurons and axons for regeneration after injury is minimal. Although a myriad... (Review)
Review
Unlike their peripheral nervous system counterparts, the capacity of central nervous system neurons and axons for regeneration after injury is minimal. Although a myriad of therapies (and different combinations thereof) to help promote repair and recovery after spinal cord injury (SCI) have been trialed, few have progressed from bench-top to bedside. One of the few such therapies that has been successfully translated from basic science to clinical applications is electrical stimulation (ES). Although the use and study of ES in peripheral nerve growth dates back nearly a century, only recently has it started to be used in a clinical setting. Since those initial experiments and seminal publications, the application of ES to restore function and promote healing have greatly expanded. In this review, we discuss the progression and use of ES over time as it pertains to promoting axonal outgrowth and functional recovery post-SCI. In doing so, we consider four major uses for the study of ES based on the proposed or documented underlying mechanism: (1) using ES to introduce an electric field at the site of injury to promote axonal outgrowth and plasticity; (2) using spinal cord ES to activate or to increase the excitability of neuronal networks below the injury; (3) using motor cortex ES to promote corticospinal tract axonal outgrowth and plasticity; and (4) leveraging the timing of paired stimuli to produce plasticity. Finally, the use of ES in its current state in the context of human SCI studies is discussed, in addition to ongoing research and current knowledge gaps, to highlight the direction of future studies for this therapeutic modality.
Topics: Animals; Clinical Trials as Topic; Humans; Nerve Regeneration; Neuronal Plasticity; Pyramidal Tracts; Recovery of Function; Spinal Cord; Spinal Cord Injuries; Spinal Cord Stimulation
PubMed: 32438858
DOI: 10.1089/neu.2020.7033 -
Experimental Neurology Nov 2019Spared corticospinal tract (CST) and proprioceptive afferent (PA) axons sprout after injury and contribute to rewiring spinal circuits, affecting motor recovery. Loss of...
Spared corticospinal tract (CST) and proprioceptive afferent (PA) axons sprout after injury and contribute to rewiring spinal circuits, affecting motor recovery. Loss of CST connections post-injury results in corticospinal signal loss and associated reduction in spinal activity. We investigated the role of activity loss and injury on CST and PA sprouting. To understand activity-dependence after injury, we compared CST and PA sprouting after motor cortex (MCX) inactivation, produced by chronic MCX muscimol microinfusion, with sprouting after a CST lesion produced by pyramidal tract section (PTx). Activity suppression, which does not produce a lesion, is sufficient to trigger CST axon outgrowth from the active side to cross the midline and to enter the inactivated side of the spinal cord, to the same extent as PTx. Activity loss was insufficient to drive significant CST gray matter axon elongation, an effect of PTx. Activity suppression triggered presynaptic site formation, but less than PTx. Activity loss triggered PA sprouting, as PTx. To understand injury-dependent sprouting further, we blocked microglial activation and associated inflammation after PTX by chronic minocycline administration after PTx. Minocycline inhibited myelin debris phagocytosis contralateral to PTx and abolished CST axon elongation, formation of presynaptic sites, and PA sprouting, but not CST axon outgrowth from the active side to cross the midline. Our findings suggest sprouting after injury has a strong activity dependence and that microglial activation after injury supports axonal elongation and presynaptic site formation. Combining spinal activity support and inflammation control is potentially more effective in promoting functional restoration than either alone.
Topics: Animals; Brain Injuries; Male; Microglia; Nerve Regeneration; Neurons; Neurons, Afferent; Pyramidal Tracts; Rats; Rats, Sprague-Dawley; Recovery of Function; Spinal Cord Injuries
PubMed: 31326353
DOI: 10.1016/j.expneurol.2019.113015 -
AJNR. American Journal of Neuroradiology Aug 2018Asymmetry of the corticospinal tract in congenital lesions is a good prognostic marker for preserved motor function after hemispherectomy. This study aimed to assess...
BACKGROUND AND PURPOSE
Asymmetry of the corticospinal tract in congenital lesions is a good prognostic marker for preserved motor function after hemispherectomy. This study aimed to assess this marker and provide a clinically feasible approach in selected cases of unilateral polymicrogyria.
MATERIALS AND METHODS
Corticospinal tract asymmetry of 9 patients with unilateral polymicrogyria substantially affecting the central region was retrospectively assessed on axial T1WI and DTI. Volumes of the brain stem and thalamus and DTI parameters of the internal capsule were measured. Two neuroradiologists independently rated the right-left asymmetry at 4 levels along the corticospinal tract. DTI tractography was used to determine the motor cortex within polymicrogyria, with task-based functional MR imaging available in 3/9 cases.
RESULTS
Visual assessment of the brain stem asymmetry showed excellent correlation with quantitative measures on both T1WI and color-coded DTI maps ( = .007 and = .023). Interrater reliability regarding structural and DTI-based corticospinal tract asymmetry was best at the midbrain (Cohen κ = 0.77, = .018). Three patients underwent functional hemispherectomy with postsurgical stable motor function, all showing marked corticospinal tract asymmetry preoperatively. Following the DTI-based corticospinal tract trajectories allowed identifying the presumed primary motor region within the dysplastic cortex in 9/9 patients, confirmed by functional MR imaging in 3/3 cases.
CONCLUSIONS
Visual assessment of corticospinal tract asymmetry in unilateral polymicrogyria involving the motor cortex is most reliable with T1WI and color-coded DTI maps at the level of the midbrain. Pronounced asymmetry predicts preserved motor function after hemispherectomy. DTI-based tractography can be used as a guidance tool to the motor cortex within polymicrogyria.
Topics: Adult; Aged; Diffusion Tensor Imaging; Female; Humans; Male; Polymicrogyria; Pyramidal Tracts; Retrospective Studies
PubMed: 29954815
DOI: 10.3174/ajnr.A5715 -
Medical Science Monitor : International... Apr 2022Limb-kinetic apraxia (LKA) is an execution disorder of movements caused by an injury to the secondary motor area (the supplementary motor area and premotor cortex) with... (Review)
Review
Limb-kinetic apraxia (LKA) is an execution disorder of movements caused by an injury to the secondary motor area (the supplementary motor area and premotor cortex) with preservation of an intact corticospinal tract (CST). A precise diagnosis of LKA is often limited because it is made based on the clinical observation of movement characteristics with confirmation of the CST state, and no specific clinical assessment tools for LKA have been developed. Diffusion tensor tractography (DTT) enables a three-dimensional estimation of the neural tracts related to LKA, such as the CST and corticofugal tract from the secondary motor area. This article reviewed 5 DTT-based studies on LKA-related neural tracts in stroke patients. These studies suggest that DTT could be a useful diagnostic tool for LKA along with previous diagnostic tools, such as brain magnetic resonance imaging and transcranial magnetic stimulation. In particular, DTT for the affected corticofugal tract can provide useful evidence for diagnosing LKA when clinicians cannot observe the movement characteristics because of severe weakness after a severe injury to the affected CST. Furthermore, a reviewed study suggested that LKA might be related to the unaffected neural tracts for motor function when the affected neural tracts were severely injured. This review summarizes the role of DTT in the diagnosis of LKA in stroke patients.
Topics: Apraxias; Diffusion Tensor Imaging; Humans; Motor Cortex; Pyramidal Tracts; Stroke
PubMed: 35431312
DOI: 10.12659/MSM.936417 -
Journal of Neurology, Neurosurgery, and... Jan 2022To investigate sensitivity of brain MRI and neurological examination for detection of upper motor neuron (UMN) degeneration in patients with amyotrophic lateral...
OBJECTIVES
To investigate sensitivity of brain MRI and neurological examination for detection of upper motor neuron (UMN) degeneration in patients with amyotrophic lateral sclerosis (ALS).
METHODS
We studied 192 patients with ALS and 314 controls longitudinally. All patients visited our centre twice and underwent full neurological examination and brain MRI. At each visit, we assessed UMN degeneration by measuring motor cortex thickness (CT) and pyramidal tract fibre density (FD) corresponding to five body regions (bulbar region and limbs). For each body region, we measured degree of clinical UMN and lower motor neuron (LMN) symptom burden using a validated scoring system.
RESULTS
We found deterioration over time of CT of motor regions (p≤0.0081) and progression of UMN signs of bulbar region and left arm (p≤0.04). FD was discriminative between controls and patients with moderate/severe UMN signs (all regions, p≤0.034), but did not change longitudinally. Higher clinical UMN burden correlated with reduced CT, but not lower FD, for the bulbar region (p=2.2×10) and legs (p≤0.025). In the arms, we found that severe LMN signs may reduce the detectability of UMN signs (p≤0.043). With MRI, UMN degeneration was detectable before UMN signs became clinically evident (CT: p=1.1×10, FD: p=6.3×10). Motor CT, but not FD, deteriorated more than UMN signs during the study period.
CONCLUSIONS
Motor CT is a more sensitive measure of UMN degeneration than UMN signs. Motor CT and pyramidal tract FD are discriminative between patients and controls. Brain MRI can monitor UMN degeneration before signs become clinically evident. These findings promote MRI as a potential biomarker for UMN progression in clinical trials in ALS.
Topics: Amyotrophic Lateral Sclerosis; Biomarkers; Case-Control Studies; Female; Humans; Magnetic Resonance Imaging; Male; Motor Cortex; Motor Neurons; Netherlands; Neuroimaging; Neurologic Examination; Pyramidal Tracts
PubMed: 34663622
DOI: 10.1136/jnnp-2021-327269 -
Neurology India Dec 2000In 1896, Joseph Babinski, a French neurologist, first described the best known neurologic eponym 'the Babinski sign'. This sign is characterised by dorsiflexion of the... (Review)
Review
In 1896, Joseph Babinski, a French neurologist, first described the best known neurologic eponym 'the Babinski sign'. This sign is characterised by dorsiflexion of the big toe and recruitment of the extensor hallucis longus muscle, on stimulating the sole of the foot. He has emphasised from the outset, the intimate relationship between this sign and the shortening movement in other leg muscles, which form the flexion synergy of the lower limb. The Babinski sign is not a new reflex, rather it is released as a result of breakdown of the harmonious integration of the flexion and extension components of the normal defence reflex mechanism, due to pyramidal tract dysfunction. A pathological Babinski sign should be clearly distinguished from upgoing toes that may not always be a part of the flexion synergy. This article reviews the Babinski sign in detail, focusing on the historical perspectives, role of pyramidal tract dysfunction and art of elicitation and interpretation. The significance of assessing this phenomenon in the entire leg, and the clinical clues that will help to dispel the myths regarding the Babinski sign, have been emphasised.
Topics: Humans; Nervous System Diseases; Neurologic Examination; Pyramidal Tracts; Reflex, Babinski
PubMed: 11146592
DOI: No ID Found -
Arquivos de Neuro-psiquiatria Oct 2011The discovery of the pyramidal syndrome and tract is briefly reviewed with emphasis on a few key historical aspects. The pursuit of the relationship between the...
The discovery of the pyramidal syndrome and tract is briefly reviewed with emphasis on a few key historical aspects. The pursuit of the relationship between the lateralized deficits resulting from contralateral head trauma begins in the fourth century BC with the Hippocratic School and continues until the present day.
Topics: History, 16th Century; History, 17th Century; History, 18th Century; History, 19th Century; History, Ancient; History, Medieval; Humans; Neurology; Pyramidal Tracts; Spinal Cord Diseases; Syndrome
PubMed: 22042191
DOI: 10.1590/s0004-282x2011000600021