scholarly journals Wallerian Degeneration in the Corticospinal Tract Following Tumefactive Demyelination: Conventional and Advanced Magnetic Resonance Imaging

2016 ◽  
Vol 43 (5) ◽  
pp. 726-727
Author(s):  
Todd A. Hardy ◽  
Chenyu Wang ◽  
Heidi N. Beadnall ◽  
Jim Lagopoulos ◽  
Yael Barnett ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Wallerian Degeneration ◽  
Corticospinal Tract ◽  
Resonance Imaging

Changes in the corticospinal tract after wearing prosthesis in bilateral transtibial amputation

2017 ◽  
Vol 41 (5) ◽  
pp. 507-511
Author(s):  
Sang Yoon Lee ◽  
Si Hyun Kang ◽  
Don-Kyu Kim ◽  
Kyung Mook Seo ◽  
Hee Joon Ro ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Diffusion Tensor Imaging ◽  
Magnetic Resonance ◽  
Primary Motor Cortex ◽  
Corticospinal Tract ◽  
Diffusion Tensor ◽  
Brain Magnetic Resonance Imaging ◽  
Resonance Imaging ◽  
Transtibial Amputation

Background:After amputation, the brain is known to be reorganized especially in the primary motor cortex. We report a case to show changes in the corticospinal tract in a patient with serial bilateral transtibial amputations using diffusion tensor imaging.Case Description and Methods:A 78-year-old man had a transtibial amputation on his left side in 2008 and he underwent a right transtibial amputation in 2011. An initial brain magnetic resonance imaging with a diffusion tensor imaging was performed before starting rehabilitation on his right transtibial prosthesis, and a follow-up magnetic resonance imaging with diffusion tensor imaging was performed 2 years after this.Findings and Outcomes:In the initial diffusion tensor imaging, the number of fiber lines in his right corticospinal tract was larger than that in his left corticospinal tract. At follow-up diffusion tensor imaging, there was no definite difference in the number of fiber lines between both corticospinal tracts.Conclusion:We found that side-to-side corticospinal tract differences were equalized after using bilateral prostheses.Clinical relevanceThis case report suggests that diffusion tensor imaging tractography could be a useful method to understand corticomotor reorganization after using prosthesis in transtibial amputation.

Intraoperative Motor Evoked Potential Alteration in Intracranial Tumor Surgery and Its Relation to Signal Alteration in Postoperative Magnetic Resonance Imaging

Neurosurgery ◽  
2010 ◽  
Vol 67 (2) ◽  
pp. 302-313 ◽  
Author(s):  
Andrea Szelényi ◽  
Elke Hattingen ◽  
Stefan Weidauer ◽  
Volker Seifert ◽  
Ulf Ziemann
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Motor Cortex ◽  
Evoked Potential ◽  
Corticospinal Tract ◽  
Motor Evoked Potential ◽  
Motor Deficit ◽  
Warning Sign ◽  
Precentral Gyrus ◽  
Resonance Imaging

Abstract OBJECTIVE To determine the degree to which the pattern of intraoperative isolated, unilateral alteration of motor evoked potential (MEP) in intracranial surgery was related to motor outcome and location of new postoperative signal alterations on magnetic resonance imaging (MRI). METHODS In 29 patients (age, 42.8 ± 18.2 years; 15 female patients; 25 supratentorial, 4 infratentorial procedures), intraoperative MEP alterations in isolation (without significant alteration in other evoked potential modalities) were classified as deterioration (> 50% amplitude decrease and/or motor threshold increase) or loss, respectively, or reversible and irreversible. Postoperative MRI was described for the location and type of new signal alteration. RESULTS New motor deficit was present in all 5 patients with irreversible MEP loss, in 7 of 10 patients with irreversible MEP deterioration, in 1 of 6 patients with reversible MEP loss, and in 0 of 8 patients with reversible MEP deterioration. Irreversible compared with reversible MEP alteration was significantly more often correlated with postoperative motor deficit (P < .0001). In 20 patients, 22 new signal alterations affected 29 various locations (precentral gyrus, n = 5; corticospinal tract, n = 19). Irreversible MEP alteration was more often associated with postoperative new signal alteration in MRI compared with reversible MEP alteration (P = .02). MEP loss was significantly more often associated with subcortically located new signal alteration (P = .006). MEP deterioration was significantly more often followed by new signal alterations located in the precentral gyrus (P = .04). CONCLUSION MEP loss bears a higher risk than MEP deterioration for postoperative motor deficit resulting from subcortical postoperative MR changes in the corticospinal tract. In contrast, MEP deterioration points to motor cortex lesion. Thus, even MEP deterioration should be considered a warning sign if surgery close to the motor cortex is performed.

scholarly journals Wallerian degeneration of the pyramidal tract in capsular infarction studied by magnetic resonance imaging.

Stroke ◽  
1990 ◽  
Vol 21 (3) ◽  
pp. 404-409 ◽  
Author(s):  
J Pujol ◽  
J L Martí-Vilalta ◽  
C Junqué ◽  
P Vendrell ◽  
J Fernández ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Wallerian Degeneration ◽  
Pyramidal Tract ◽  
Resonance Imaging ◽  
Capsular Infarction

scholarly journals Assessment of a Reliable Fractional Anisotropy Cutoff in Tractography of the Corticospinal Tract for Neurosurgical Patients

2021 ◽  
Vol 11 (5) ◽  
pp. 650
Author(s):  
Tim Wende ◽  
Johannes Kasper ◽  
Florian Wilhelmy ◽  
Eric Dietel ◽  
Gordian Hamerla ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Fractional Anisotropy ◽  
Corticospinal Tract ◽  
Diffusion Tensor ◽  
False Negative ◽  
Standard Technique ◽  
Resonance Imaging ◽  
Cutoff Value ◽  
Neurosurgical Patients

Background: Tractography has become a standard technique for planning neurosurgical operations in the past decades. This technique relies on diffusion magnetic resonance imaging. The cutoff value for the fractional anisotropy (FA) has an important role in avoiding false-positive and false-negative results. However, there is a wide variation in FA cutoff values. Methods: We analyzed a prospective cohort of 14 patients (six males and eight females, 50.1 ± 4.0 years old) with intracerebral tumors that were mostly gliomas. Magnetic resonance imaging (MRI) was obtained within 7 days before and within 7 days after surgery with T1 and diffusion tensor image (DTI) sequences. We, then, reconstructed the corticospinal tract (CST) in all patients and extracted the FA values within the resulting volume. Results: The mean FA in all CSTs was 0.4406 ± 0.0003 with the fifth percentile at 0.1454. FA values in right-hemispheric CSTs were lower (p < 0.0001). Postoperatively, the FA values were more condensed around their mean (p < 0.0001). The analysis of infiltrated or compressed CSTs revealed a lower fifth percentile (0.1407 ± 0.0109 versus 0.1763 ± 0.0040, p = 0.0036). Conclusion: An FA cutoff value of 0.15 appears to be reasonable for neurosurgical patients and may shorten the tractography workflow. However, infiltrated fiber bundles must trigger vigilance and may require lower cutoffs.

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