Intraoperative magnetic resonance imaging–guided tractography with integrated monopolar subcortical functional mapping for resection of brain tumors

2011 ◽  
Vol 114 (3) ◽  
pp. 719-726 ◽  
Author(s):  
Sujit S. Prabhu ◽  
Jaime Gasco ◽  
Sudhakar Tummala ◽  
Jefrey S. Weinberg ◽  
Ganesh Rao
Keyword(s):  
Brain Tumors ◽  
Diffusion Tensor ◽  
Tumor Resection ◽  
Motor Evoked Potential ◽  
Neurological Deficits ◽  
Resection Margins ◽  
Neurological Outcomes ◽  
Close Proximity ◽  
The Mean ◽  
Subcortical Mapping

Object The object of this study was to describe the utility and safety of using a single probe for combined intraoperative navigation and subcortical mapping in an intraoperative MR (iMR) imaging environment during brain tumor resection. Methods The authors retrospectively reviewed those patients who underwent resection in the iMR imaging environment, as well as functional electrophysiological monitoring with continuous motor evoked potential (MEP) and direct subcortical mapping combined with diffusion tensor imaging tractography. Results As a navigational tool the monopolar probe used was safe and accurate. Positive subcortical fiber MEPs were obtained in 10 (83%) of the 12 cases. In 10 patients in whom subcortical MEPs were recorded, the mean stimulus intensity was 10.4 ± 5.2 mA and the mean distance from the probe tip to the corticospinal tract (CST) was 7.4 ± 4.5 mm. There was a trend toward worsening neurological deficits if the distance to the CST was short, and a small minimum stimulation threshold was recorded indicating close proximity of the CST to the resection margins. Gross-total resection (95%–100% tumor removal) was achieved in 11 cases (92%), whereas 1 patient (8%) had at least a 90% tumor resection. At the end of 3 months, 2 patients (17%) had persistent neurological deficits. Conclusions The monopolar probe can be safely implemented in an iMR imaging environment both for navigation and stimulation purposes during the resection of intrinsic brain tumors. In this study there was a trend toward worsening neurological deficits if the distance from the probe to the CST was short (< 5 mm) indicating close proximity of the resection cavity to the CST. This technology can be used in the iMR imaging environment as a surgical adjunct to minimize adverse neurological outcomes.

scholarly journals Multimodal navigation in the functional microsurgical resection of intrinsic brain tumors located in eloquent motor areas: role of tractography

2010 ◽  
Vol 28 (2) ◽  
pp. E5 ◽  
Author(s):  
José M. González-Darder ◽  
Pablo González-López ◽  
Fernando Talamantes ◽  
Vicent Quilis ◽  
Victoria Cortés ◽  
...  
Keyword(s):  
Brain Tumors ◽  
Functional Data ◽  
Motor Response ◽  
Diffusion Tensor ◽  
Neurological Deficits ◽  
Motor Mapping ◽  
Wave Inversion ◽  
The Mean ◽  
Motor Areas

Object Nowadays the role of microsurgical management of intrinsic brain tumors is to maximize the volumetric resection of the tumoral tissue, minimizing the postoperative morbidity. The purpose of this paper was to study the benefits of an original protocol developed for the microsurgical treatment of tumors located in eloquent motor areas where the navigation and electrical stimulation of motor subcortical pathways have been implemented. Methods A total of 17 patients who underwent resection of cortical or subcortical tumors in motor areas have been included in the series. The preoperative planning for multimodal navigation was done by integrating anatomical studies, motor functional MR (fMR) imaging, and subcortical pathway volumes generated by diffusion tensor (DT) imaging. Intraoperative neuromonitoring included motor mapping by direct cortical stimulation (CS) and subcortical stimulation (sCS), and localization of the central sulcus by using cortical multipolar electrodes and the N20 wave inversion technique. The location of all cortically and subcortically stimulated points with positive motor response was stored in the navigator and correlated with the cortical and subcortical motor functional structures defined preoperatively. Results The mean tumoral volumetric resection was 89.1 ± 14.2% of the preoperative volume, with a total resection (≥ 100%) in 8 patients. Preoperatively a total of 58.8% of the patients had some kind of motor neurological deficit, increasing 24 hours after surgery to 70.6% and decreasing to 47.1% at 1 month later. There was a great correlation between anatomical and functional data, both cortically and subcortically. A total of 52 cortical points submitted to CS had positive motor response, with a positive correlation of 83.7%. Also, a total of 55 subcortical points had positive motor response; in these cases the mean distance from the stimulated point to the subcortical tract was 7.3 ± 3.1 mm. Conclusions The integration of anatomical and functional studies allows a safe functional resection of the brain tumors located in eloquent areas. Multimodal navigation allows integration and correlation among preoperative and intraoperative anatomical and functional data. Cortical motor functional areas are anatomically and functionally located preoperatively thanks to MR and fMR imaging and subcortical motor pathways with DT imaging and tractography. Intraoperative confirmation is done with CS and N20 inversion wave for cortical structures and with sCS for subcortical pathways. With this protocol the authors achieved a good volumetric resection in cortical and subcortical tumors located in eloquent motor areas, with an increase in the incidence of neurological deficits in the immediate postoperative period that significantly decreased 1 month later. Ongoing studies must define the safe limits for functional resection, taking into account the intraoperative brain shift. Finally, it must be demonstrated whether this protocol has any long-term benefit for patients by prolonging the disease-free interval, the time to recurrence, or the survival time.

Awake craniotomy for gliomas in a high-field intraoperative magnetic resonance imaging suite: analysis of 42 cases

2014 ◽  
Vol 121 (4) ◽  
pp. 810-817 ◽  
Author(s):  
Marcos V. C. Maldaun ◽  
Shumaila N. Khawja ◽  
Nicholas B. Levine ◽  
Ganesh Rao ◽  
Frederick F. Lang ◽  
...  
Keyword(s):  
High Field ◽  
Tumor Resection ◽  
Patient Positioning ◽  
Extent Of Resection ◽  
Awake Craniotomy ◽  
Neurological Deficits ◽  
Speech Mapping ◽  
Duration Of Surgery ◽  
The Mean ◽  
Subcortical Mapping

Object The object of this study was to describe the experience of combining awake craniotomy techniques with high-field (1.5 T) intraoperative MRI (iMRI) for tumors adjacent to eloquent cortex. Methods From a prospective database the authors obtained and evaluated the records of all patients who had undergone awake craniotomy procedures with cortical and subcortical mapping in the iMRI suite. The integration of these two modalities was assessed with respect to safety, operative times, workflow, extent of resection (EOR), and neurological outcome. Results Between February 2010 and December 2011, 42 awake craniotomy procedures using iMRI were performed in 41 patients for the removal of intraaxial tumors. There were 31 left-sided and 11 right-sided tumors. In half of the cases (21 [50%] of 42), the patient was kept awake for both motor and speech mapping. The mean duration of surgery overall was 7.3 hours (range 4.0–13.9 hours). The median EOR overall was 90%, and gross-total resection (EOR ≥ 95%) was achieved in 17 cases (40.5%). After viewing the first MR images after initial resection, further resection was performed in 17 cases (40.5%); the mean EOR in these cases increased from 56% to 67% after further resection. No deficits were observed preoperatively in 33 cases (78.5%), and worsening neurological deficits were noted immediately after surgery in 11 cases (26.2%). At 1 month after surgery, however, worsened neurological function was observed in only 1 case (2.3%). Conclusions There was a learning curve with regard to patient positioning and setup times, although it did not adversely affect patient outcomes. Awake craniotomy can be safely performed in a high-field (1.5 T) iMRI suite to maximize tumor resection in eloquent brain areas with an acceptable morbidity profile at 1 month.

Associations between clinical outcome and tractography based on navigated transcranial magnetic stimulation in patients with language-eloquent brain lesions

2020 ◽  
Vol 132 (4) ◽  
pp. 1033-1042 ◽  
Author(s):  
Nico Sollmann ◽  
Alessia Fratini ◽  
Haosu Zhang ◽  
Claus Zimmer ◽  
Bernhard Meyer ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Brain Tumors ◽  
Risk Stratification ◽  
Magnetic Stimulation ◽  
Diffusion Tensor ◽  
Tumor Resection ◽  
Navigated Transcranial Magnetic Stimulation ◽  
Language Mapping ◽  
Significant Difference ◽  
Related Pathway

OBJECTIVENavigated transcranial magnetic stimulation (nTMS) in combination with diffusion tensor imaging fiber tracking (DTI FT) is increasingly used to locate subcortical language-related pathways. The aim of this study was to establish nTMS-based DTI FT for preoperative risk stratification by evaluating associations between lesion-to-tract distances (LTDs) and aphasia and by determining a cut-off LTD value to prevent surgery-related permanent aphasia.METHODSFifty patients with left-hemispheric, language-eloquent brain tumors underwent preoperative nTMS language mapping and nTMS-based DTI FT, followed by tumor resection. nTMS-based DTI FT was performed with a predefined fractional anisotropy (FA) of 0.10, 0.15, 50% of the individual FA threshold (FAT), and 75% FAT (minimum fiber length [FL]: 100 mm). The arcuate fascicle (AF), superior longitudinal fascicle (SLF), inferior longitudinal fascicle (ILF), uncinate fascicle (UC), and frontooccipital fascicle (FoF) were identified in nTMS-based tractography, and minimum LTDs were measured between the lesion and the AF and between the lesion and the closest other subcortical language-related pathway (SLF, ILF, UC, or FoF). LTDs were then associated with the level of aphasia (no/transient or permanent surgery-related aphasia, according to follow-up examinations).RESULTSA significant difference in LTDs was observed between patients with no or only surgery-related transient impairment and those who developed surgery-related permanent aphasia with regard to the AF (FA = 0.10, p = 0.0321; FA = 0.15, p = 0.0143; FA = 50% FAT, p = 0.0106) as well as the closest other subcortical language-related pathway (FA = 0.10, p = 0.0182; FA = 0.15, p = 0.0200; FA = 50% FAT, p = 0.0077). Patients with surgery-related permanent aphasia showed the lowest LTDs in relation to these tracts. Thus, LTDs of ≥ 8 mm (AF) and ≥ 11 mm (SLF, ILF, UC, or FoF) were determined as cut-off values for surgery-related permanent aphasia.CONCLUSIONSnTMS-based DTI FT of subcortical language-related pathways seems suitable for risk stratification and prediction in patients suffering from language-eloquent brain tumors. Thus, the current role of nTMS-based DTI FT might be expanded, going beyond the level of being a mere tool for surgical planning and resection guidance.

CNTM-01. Evaluating Traditional and Non-Traditional Eloquent Areas in Patients with Brain Tumors: Large-scale Network Analysis Using a Machine Learning-Based Platform

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi224-vi224
Author(s):  
Alexis Morell ◽  
Daniel Eichberg ◽  
Ashish Shah ◽  
Evan Luther ◽  
Victor Lu ◽  
...  
Keyword(s):  
Machine Learning ◽  
Brain Tumors ◽  
Large Scale ◽  
Diffusion Tensor ◽  
Brain Networks ◽  
Tumor Resection ◽  
Central Executive ◽  
Default Mode ◽  
Eloquent Areas ◽  
Neurologic Deficits

Abstract BACKGROUND Developing mapping tools that allow identification of traditional or non-traditional eloquent areas is necessary to minimize the risk of postoperative neurologic deficits. The objective of our study is to evaluate the use of a novel cloud-based platform that uses machine learning to identify cerebral networks in patients with brain tumors. METHODS We retrospectively included all adult patients who underwent surgery for brain tumor resection or thermal ablation at our Institution between the 16th of February and the 15th of May of 2021. Pre and postoperative contrast-enhanced MRI with T1-weighted and high-resolution Diffusion Tensor Imaging (DTI) sequences were uploaded into the Quicktome platform. After processing the data, we categorized the integrity of seven large-scale brain networks: sensorimotor, visual, ventral attention, central executive, default mode, dorsal attention and limbic. Affected networks were correlated with pre and postoperative clinical data, including neurologic deficits. RESULTS Thirty-five (35) patients were included in the study. The average age of the sample was 63.2 years, and 51.4% (n=18) were females. The most affected network was the central executive network (40%), followed by the dorsal attention and default mode networks (31.4%), while the least affected were the visual (11%) and ventral attention networks (17%). Patients with preoperative deficits showed a significantly higher number of altered networks before the surgery (p=0.021), compared to patients without deficits. In addition, we found that patients without neurologic deficits had an average of 2.06 large-scale networks affected, with 75% of them not being related to traditional eloquent areas as the sensorimotor, language or visual circuits. CONCLUSIONS The Quicktome platform is a practical tool that allows automatic visualization of large-scale brain networks in patients with brain tumors. Although further studies are needed, it may assist in the surgical management of traditional and non-traditional eloquent areas.

scholarly journals The influence of anaesthesia on intraoperative neuromonitoring changes in high-risk spinal surgery

2017 ◽  
Vol 04 (03) ◽  
pp. 159-166
Author(s):  
Nathan Royan ◽  
Nancy Lu ◽  
Pirjo Manninen ◽  
Lakshmikumar Venkatraghavan
Keyword(s):  
High Risk ◽  
Spinal Surgery ◽  
Statistical Difference ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Intraoperative Neuromonitoring ◽  
Neurological Deficits ◽  
Neurophysiological Monitoring ◽  
Surgical Interventions ◽  
Neurological Outcomes

Abstract Background: The use of intraoperative neuromonitoring is a well-established method of detecting neurologic injuries during spine surgery. Anaesthesia, especially inhalational agents, influence motor evoked potential (MEP) monitoring. The aim of our study was to compare the effect of balanced anaesthesia (BA) (intravenous plus inhalational anaesthesia) and total intravenous anaesthesia (TIVA) on the incidence of intraoperative neuromonitoring changes, interventions performed and neurological outcomes of patients following high-risk spinal surgery. Methods: After Research and Ethics Board approval, a retrospective review of 155 patients who underwent spinal surgery with MEP was performed. Data were collected on changes in MEP and/or somatosensory evoked potential, interventions performed and neurological outcomes. Patients were divided into BA and TIVA groups and data were analysed. Results: A total of 152 patients were eligible for the study (mean age 54 ± 17, male: female 45:55). A BA technique was used in 62% and TIVA in 38%. Desflurane (<0.5 minimum alveolar concentration [MAC]) was used in 85% BA cases. Intraoperative neuromonitoring changes occurred in 11.8% (18/152) of cases. There was no statistical difference in the incidence of monitoring changes between BA (78%) and TIVA (22%) groups (P = 0.197). Anaesthetic or surgical interventions were performed in 12 patients, with a resolution of changes in 50% (P = 0.455). All 5 patients with persistent MEP changes had worsening of existing neurological deficits postoperatively; 8 had transient MEP changes, and 2 experienced worsening of existing neurological deficits. Conclusions: We found that intraoperative neurophysiological monitoring can be performed with both BA (MAC <0.5) and TIVA in high-risk spinal surgery with no statistical difference in the incidence of intraoperative monitoring changes.

NCOG-46. WHITE MATTER TRACT INVOLVEMENT BY INTRA-AXIAL BRAIN TUMORS; DIAGNOSTIC & THERAPEUTIC IMPLICATIONS

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi162-vi162
Author(s):  
Saqib Kamran Bakhshi ◽  
Ayesha Quddusi ◽  
Danish Mahmood ◽  
Muhammad Waqas ◽  
Muhammad Shahzad Shamim ◽  
...  
Keyword(s):  
White Matter ◽  
Brain Tumors ◽  
Functional Outcome ◽  
Diffusion Tensor ◽  
Tumor Resection ◽  
Karnofsky Performance Scale ◽  
Low Grade ◽  
High Grade ◽  
Poor Functional Outcome

Abstract Diffusion tensor imaging (DTI) is a relatively recent modality which aids in visualization of WMT and their relation to intracranial lesions. Despite almost two decades since the beginning of its use in tumor resection, there is still dearth of data on its diagnostic and prognostic value from low- and middle-income countries. We aimed to assess the pattern of involvement of white matter tracts (WMT) by intra-axial brain tumors on DTI. Secondary objectives were to evaluate implications of involvement of WMT on surgical resection, and post-operative functional outcome. This was a retrospective study of 77 consecutive patients, who underwent DTI guided surgery for brain tumors. The involvement of WMT by tumors on DTI was assessed by a radiologist (who was blind to the pathology) using the Witwer classification. The pathology was reported by histopathologists using WHO brain tumor classification. Karnofsky Performance Scale (KPS) was used for assessing patients’ neurological status at admission, and at follow-up. Forty-five (58.4%) out of 77 tumors reviewed, caused infiltration of WMT, whereas only 22 (28.6%) tumors caused displacement of WMT (p = 0.040). Among 32 cases of astrocytoma, involvement of WMTs was influenced by the grade of tumor (p = 0.012), as high-grade tumors caused infiltration (19; 59.4%), unlike low grade tumors which commonly caused displacement (2; 50%). Oligodendroglioma caused infiltration/disruption of WMTs in most cases, irrespective of the grade (19 out of 25 cases; 76%). At last follow-up, 27 (35.1%) patients showed improvement in KPS and 14 (18.2%) reported deterioration, while there was no change observed in 36 (46.8%) patients. Infiltration of WMTs was associated with poor functional outcome. We conclude that intra-axial brain tumors mostly cause infiltration of WMTs, particularly high-grade astrocytoma, and oligodendroglioma of any grade. Infiltration of WMTs is associated with poor functional outcome at follow-up.

Association between postoperative DTI metrics and neurological deficits after posterior fossa tumor resection in children

2019 ◽  
Vol 24 (4) ◽  
pp. 364-370 ◽  
Author(s):  
Aditya Vedantam ◽  
Katie M. Stormes ◽  
Nisha Gadgil ◽  
Stephen F. Kralik ◽  
Guillermo Aldave ◽  
...  
Keyword(s):  
Posterior Fossa ◽  
Median Duration ◽  
Structural Damage ◽  
Diffusion Tensor ◽  
Statistical Significance ◽  
Tumor Resection ◽  
Neurological Deficits ◽  
Posterior Fossa Tumors ◽  
Cerebellar Peduncles

OBJECTIVEResection of posterior fossa tumors in children may be associated with persistent neurological deficits. It is unclear if these neurological deficits are associated with persistent structural damage to the cerebellar pathways. The purpose of this research was to define longitudinal changes in diffusion tensor imaging (DTI) metrics in white matter cerebellar tracts and the clinical correlates of these metrics in children undergoing resection of posterior fossa tumors.METHODSLongitudinal brain DTI was performed in a cohort of pediatric patients who underwent resection of posterior fossa tumors. Fractional anisotropy (FA) of the superior cerebellar peduncles (SCPs) and middle cerebellar peduncles (MCPs) was measured on preoperative, postoperative, and follow-up DTI. Early postoperative (< 48 hours) and longer-term follow-up neurological deficits (mutism, ataxia, and extraocular movement dysfunction) were documented. Statistical analysis was performed to determine differences in FA values based on presence or absence of neurological deficits. Statistical significance was set at p < 0.05.RESULTSTwenty children (mean age 6.1 ± 4.1 years [SD], 12 males and 8 females) were included in this study. Follow-up DTI was performed at a median duration of 14.3 months after surgery, and the median duration of follow-up was 19.7 months. FA of the left SCP was significantly reduced on postoperative DTI in comparison with preoperative DTI (0.44 ± 0.07 vs 0.53 ± 0.1, p = 0.003). Presence of ataxia at follow-up was associated with a persistent reduction in the left SCP FA on follow-up DTI (0.43 ± 0.1 vs 0.55 ± 0.1, p = 0.016). Patients with early postoperative mutism who did not recover at follow-up had significantly decreased FA of the left SCP on early postoperative DTI in comparison with those who recovered (0.38 ± 0.05 vs 0.48 ± 0.06, p = 0.04).CONCLUSIONSDTI after resection of posterior fossa tumors in children shows that persistent reduction of SCP FA is associated with ataxia at follow-up.

Feasibility of intraoperative monitoring of motor evoked potentials obtained through transcranial electrical stimulation in infants younger than 3 months

2019 ◽  
Vol 23 (6) ◽  
pp. 758-766 ◽  
Author(s):  
You Gyoung Yi ◽  
Keewon Kim ◽  
Hyung-Ik Shin ◽  
Moon Suk Bang ◽  
Hee-Soo Kim ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Motor Evoked Potentials ◽  
Young Patients ◽  
Motor Evoked Potential ◽  
The Other ◽  
Neurological Deficits ◽  
Transcranial Electrical Stimulation ◽  
Neurosurgical Procedures ◽  
Limb Weakness ◽  
The Mean

OBJECTIVEThis study aimed to investigate the feasibility and safety of intraoperative motor evoked potential (MEP) monitoring in infants less than 3 months of age.METHODSThe authors investigated 25 cases in which infants younger than 3 months (mean age 72.8 days, range 39–87) underwent neurosurgery between 2014 and 2017. Myogenic MEPs were obtained through transcranial electrical stimulation. In all cases, surgery was performed under total intravenous anesthesia, maintained with remifentanil and propofol.RESULTSMEPs were documented in 24 infants, the sole exception being 1 infant who was lethargic and had 4-limb weakness before surgery. The mean stimulation intensity maintained during monitoring was 596 ± 154 V (range 290–900 V). In 19 of 24 infants MEP signals remained at ≥ 50% of the baseline amplitude throughout the operation. Among 5 cases with a decrease in intraoperative MEP amplitude, the MEP signal was recovered in one during surgery, and in the other case a neurological examination could not be performed after surgery. In the other 3 cases, 2 infants had relevant postoperative weakness and the other did not show postoperative neurological deficits. Postoperative weakness was not observed in any of the 20 infants who had no deterioration (n = 19) or only temporary deterioration (n = 1) in MEP signal during surgery.CONCLUSIONSTranscranial electrical MEPs could be implemented during neurosurgery in infants between 1 and 3 months of age. Intraoperative MEP monitoring may be a safe adjunct for neurosurgical procedures in these very young patients.

Diffusion Tensor Imaging Color-Coded Maps: An Alternative to Tractography

2021 ◽  
pp. 1-10
Author(s):  
Julia R. Schneider ◽  
Ami B. Raval ◽  
Karen Black ◽  
Michael Schulder
Keyword(s):  
Diffusion Tensor Imaging ◽  
White Matter ◽  
Diffusion Tensor ◽  
Pyramidal Tract ◽  
Tumor Resection ◽  
Cavernous Angioma ◽  
Tumor Location ◽  
White Matter Tract ◽  
White Matter Tracts ◽  
Neurological Outcomes

<b><i>Introduction:</i></b> White matter tracts can be observed using tractograms generated from diffusion tensor imaging (DTI). However, the dependence of these white matter tract images on subjective variables, including how seed points are placed and the preferred level of fractional anisotropy, introduces interobserver inconsistency and potential lack of reliability. We propose that color-coded maps (CCM) generated from DTI can be a preferred method for the visualization of important white matter tracts, circumventing bias in preoperative brain tumor resection planning. <b><i>Methods:</i></b> DTI was acquired retrospectively in 25 patients with brain tumors. Lesions included 15 tumors of glial origin, 9 metastatic tumors, 2 meningiomas, and 1 cavernous angioma. Tractograms of the pyramidal tract and/or optic radiations, based on tumor location, were created by marking seed regions of interest using known anatomical locations. We compared the degree of tract involvement and white matter alteration between CCMs and tractograms. Neurological outcomes were obtained from chart reviews. <b><i>Results:</i></b> The pyramidal tract was evaluated in 20/25 patients, the visual tracts were evaluated in 10/25, and both tracts were evaluated in 5/25. In 19/25 studies, the same patterns of white matter alternations were found between the CCMs and tractograms. In the 6 patients where patterns differed, 2 tractograms were not useful in determining pattern alteration; in the remaining 4/6, no practical difference was seen in comparing the studies. Two patients were lost to follow-up. Thirteen patients were neurologically improved or remained intact after intervention. In these, 10 of the 13 patients showed tumor-induced white matter tract displacement on CCM. Twelve patients had no improvement of their preoperative deficit. In 9 of these 12 patients, CCM showed white matter disruption. <b><i>Conclusion:</i></b> CCMs provide a convenient, practical, and objective method of visualizing white matter tracts, obviating the need for potentially subjective and time-consuming tractography. CCMs are at least as reliable as tractograms in predicting neurological outcomes after neurosurgical intervention.

Comparison between motor evoked potential recording and fiber tracking for estimating pyramidal tracts near brain tumors

2007 ◽  
Vol 106 (1) ◽  
pp. 128-133 ◽  
Author(s):  
Nobuhiro Mikuni ◽  
Tsutomu Okada ◽  
Namiko Nishida ◽  
Junya Taki ◽  
Rei Enatsu ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Brain Tumors ◽  
Evoked Potential ◽  
Pyramidal Tract ◽  
Tumor Resection ◽  
Motor Evoked Potential ◽  
Fiber Tracking ◽  
Corona Radiata ◽  
Pyramidal Tracts ◽  
Neuronavigation System

Object The utility of subcortical electrical stimulation and fiber tracking were compared to estimate the pyramidal tract near brain tumors. Methods In 22 patients, the white matter at the bottom of a tumor was electrically stimulated near the fiber tracking of the pyramidal tract shown on a neuronavigation system. The distance between the center of the fiber tracking of these tracts and the stimulated region was measured and defined as the motor evoked potential (MEP) response. The MEP was consistently produced at distances less than 7 mm (six patients), but was consistently absent at distances more than 13 mm (seven patients) from the fiber tracking of the pyramidal tracts. In the nine patients in whom the distance was between 8 and 12 mm, an MEP was elicited when stimulation was applied at the level of the corona radiata. Motor function was preserved or even improved with appropriate tumor resection in all patients. Conclusions The anteroposteriorly running superior longitudinal fasciculus could cause complications in the fiber tracking of upper-extremity motor pathways at the level of the corona radiata. During resection of tumors located near the corona radiata, subcortical electrical stimulation should be applied at some distance from the pyramidal tract, as estimated by fiber tracking.

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