RESUMO
OBJECTIVE: The aims of this study were to 1) assess and quantify white matter (WM) microstructural characteristics derived from diffusion tensor imaging (DTI) in children with cerebral palsy (CP) prior to selective dorsal rhizotomy (SDR), and 2) investigate potential associations between WM diffusion properties and gross motor function and spasticity in children with spastic CP who underwent SDR. METHODS: This study is a multisite study based on DT images acquired prior to SDR as well as postoperative outcome data. DTI data collected from two sites were harmonized using the ComBat approach to minimize intersite scanner difference. The DTI abnormalities between children with spastic CP and controls were analyzed and correlated with the severity of impaired mobility based on the Gross Motor Function Classification System (GMFCS). The improvement in gross motor function and spasticity after SDR surgery was assessed utilizing the Gross Motor Function Measure-66 (GMFM-66), the Modified Tardieu Scale (MTS), and the modified Ashworth scale (MAS). Alterations in these outcome measures were quantified in association with DTI abnormalities. RESULTS: Significant DTI alterations, including lower fractional anisotropy (FA) in the genu of the corpus callosum (gCC) and higher mean diffusivity (MD) in the gCC and posterior limb of the internal capsule (PLIC), were found in children in the SDR group when compared with the age-matched control group (all p < 0.05). Greater DTI alterations (FA in gCC and MD in gCC and PLIC) were associated with lower mobility levels as determined based on GMFCS level (p < 0.05). The pre- to post-SDR improvement in motor function based on GMFM-66 was statistically significant (p = 0.006 and 0.002 at 6-month and 12-month follow-ups, respectively). The SDR efficacy was also identified as improving spasticity in lower-extremity muscle groups assessed with the MTS and MAS. Partial correlation analysis presented a significant association between pre- to post-SDR MTS alteration and DTI abnormalities. CONCLUSIONS: The findings in the present study provided initial quantitative evidence to establish the WM microstructural characteristics in children with spastic CP prior to SDR surgery. The study generated data for the association between baseline DTI characteristics and mobility in children with CP prior to SDR surgery. The study also demonstrated SDR efficacy in improving motor function and spasticity based on the GMFM-66, MTS, and MAS, respectively, in association with DTI data.
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Paralisia Cerebral , Imagem de Tensor de Difusão , Rizotomia , Substância Branca , Humanos , Paralisia Cerebral/cirurgia , Paralisia Cerebral/diagnóstico por imagem , Paralisia Cerebral/complicações , Imagem de Tensor de Difusão/métodos , Rizotomia/métodos , Criança , Masculino , Feminino , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Substância Branca/patologia , Pré-Escolar , Espasticidade Muscular/cirurgia , Espasticidade Muscular/diagnóstico por imagem , Espasticidade Muscular/etiologia , Adolescente , Resultado do Tratamento , Anisotropia , Corpo Caloso/diagnóstico por imagem , Corpo Caloso/cirurgiaRESUMO
OBJECTIVE: Anatomy and connections of the supplementary motor area (SMA) are studied essentially to analyze the SMA syndrome. Experience with surgical treatment of 19 tumors located in SMA is analyzed. MATERIAL AND METHODS: The cortical anatomy and subcortical connectivity of the SMA was studied on ten previously frozen and formalin fixed human cadaveric brain specimens. The white fiber dissection was performed using Klingler's method. Nineteen patients with low grade gliomas in the region of the SMA treated surgically were clinically analyzed. RESULTS: The white fiber connections of the SMA include short arcuate connections with the pre-central, middle and inferior frontal gyri, the medial part of the SLF, the cingulum, the frontal aslant tract (FAT), the claustro-cortical fibers, the fronto-striatal tract and the crossed frontal aslant tract. All tumors were operated using en-masse surgical technique described by us and its subsequent modifications that focused on attempts towards preservation of related critical fiber tracts namely FAT, cingulum and corpus callosum presumed to be responsible for postoperative SMA syndrome. Eight patients developed an SMA syndrome in the immediate post-operative period. Eleven patients did not develop any post-operative neurological deficits. In all these 11 patients it was apparent that the cingulum, FAT and the corpus callosal fibers were preserved during surgery by modifying the tumor resection technique. CONCLUSIONS: SMA syndrome is a frequent occurrence following surgery in patients with tumors in the region of the SMA complex. Surgical strategy that preserves the cingulum and the FAT can prevent the occurrence of the SMA syndrome.
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Neoplasias Encefálicas , Glioma , Córtex Motor , Substância Branca , Humanos , Feminino , Masculino , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/patologia , Adulto , Pessoa de Meia-Idade , Substância Branca/cirurgia , Substância Branca/patologia , Substância Branca/diagnóstico por imagem , Glioma/cirurgia , Glioma/patologia , Córtex Motor/cirurgia , Córtex Motor/patologia , Adulto Jovem , Adolescente , Procedimentos Neurocirúrgicos/métodos , Vias Neurais/cirurgia , Vias Neurais/patologia , CriançaRESUMO
OBJECTIVE: The aim of this study was to explore the relation of language functional MRI (fMRI)-guided tractography with postsurgical naming decline in people with temporal lobe epilepsy (TLE). METHODS: Twenty patients with unilateral TLE (9 left) were studied with auditory and picture naming functional MRI tasks. Activation maxima in the left posterobasal temporal lobe were used as seed regions for whole-brain fibre tractography. Clinical naming performance was assessed preoperatively, 4 months, and 12 months following temporal lobe resection. Volumes of white matter language tracts in both hemispheres as well as tract volume laterality indices were explored as moderators of postoperative naming decline using Pearson correlations and multiple linear regression with other clinical variables. RESULTS: Larger volumes of white matter language tracts derived from auditory and picture naming maxima in the hemisphere of subsequent surgery as well as stronger lateralization of picture naming tract volumes to the side of surgery correlated with greater language decline, which was independent of fMRI lateralization status. Multiple regression for picture naming tract volumes was associated with a significant decline of naming function with 100% sensitivity and 93% specificity at both short-term and long-term follow-up. INTERPRETATION: Naming fMRI-guided white matter language tract volumes relate to postoperative naming decline after temporal lobe resection in people with TLE. This can assist stratification of surgical outcome and minimize risk of postoperative language deficits in TLE.
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Epilepsia do Lobo Temporal , Imageamento por Ressonância Magnética , Lobo Temporal , Substância Branca , Humanos , Masculino , Feminino , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Adulto , Epilepsia do Lobo Temporal/cirurgia , Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/fisiopatologia , Pessoa de Meia-Idade , Lobo Temporal/cirurgia , Lobo Temporal/diagnóstico por imagem , Lobo Temporal/fisiopatologia , Imagem de Tensor de Difusão , Adulto Jovem , Transtornos da Linguagem/etiologia , Transtornos da Linguagem/diagnóstico por imagem , Transtornos da Linguagem/fisiopatologia , Lateralidade Funcional/fisiologia , Complicações Pós-Operatórias/diagnóstico por imagem , Complicações Pós-Operatórias/etiologia , Complicações Pós-Operatórias/fisiopatologia , Idioma , Vias Neurais/diagnóstico por imagem , Vias Neurais/fisiopatologia , Vias Neurais/cirurgiaRESUMO
PURPOSE: Wide-field imaging Mueller polarimetry is a revolutionary, label-free, and non-invasive modality for computer-aided intervention; in neurosurgery, it aims to provide visual feedback of white matter fibre bundle orientation from derived parameters. Conventionally, robust polarimetric parameters are estimated after averaging multiple measurements of intensity for each pair of probing and detected polarised light. Long multi-shot averaging, however, is not compatible with real-time in vivo imaging, and the current performance of polarimetric data processing hinders the translation to clinical practice. METHODS: A learning-based denoising framework is tailored for fast, single-shot, noisy acquisitions of polarimetric intensities. Also, performance-optimised image processing tools are devised for the derivation of clinically relevant parameters. The combination recovers accurate polarimetric parameters from fast acquisitions with near-real-time performance, under the assumption of pseudo-Gaussian polarimetric acquisition noise. RESULTS: The denoising framework is trained, validated, and tested on experimental data comprising tumour-free and diseased human brain samples in different conditions. Accuracy and image quality indices showed significant ( p < 0.05 ) improvements on testing data for a fast single-pass denoising versus the state-of-the-art and high polarimetric image quality standards. The computational time is reported for the end-to-end processing. CONCLUSION: The end-to-end image processing achieved real-time performance for a localised field of view ( ≈ 6.5 mm 2 ). The denoised polarimetric intensities produced visibly clear directional patterns of neuronal fibre tracts in line with reference polarimetric image quality standards; directional disruption was kept in case of neoplastic lesions. The presented advances pave the way towards feasible oncological neurosurgical translations of novel, label-free, interventional feedback.
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Processamento de Imagem Assistida por Computador , Procedimentos Neurocirúrgicos , Humanos , Procedimentos Neurocirúrgicos/métodos , Processamento de Imagem Assistida por Computador/métodos , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/diagnóstico por imagem , Cirurgia Assistida por Computador/métodos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgiaRESUMO
Hemifacial spasm (HFS) is a syndrome characterized by involuntary contractions of the facial muscles innervated by the ipsilateral facial nerve. Currently, microvascular decompression (MVD) is an effective treatment for HFS. Diffusion weighted imaging (DWI) is a non-invasive advanced magnetic resonance technique that allows us to reconstruct white matter (WM) virtually based on water diffusion direction. This enables us to model the human brain as a complex network using graph theory. In our study, we recruited 32 patients with HFS and 32 healthy controls to analyze and compare the topological organization of whole-brain white matter networks between the groups. We also explored the potential relationships between altered topological properties and clinical outcomes. Compared to the HC group, the white matter network was disrupted in both preoperative and postoperative groups of HFS patients, mainly located in the somatomotor network, limbic network, and default network (All P < 0.05, FDR corrected). There was no significant difference between the preoperative and postoperative groups (P > 0.05, FDR corrected). There was a correlation between the altered topological properties and clinical outcomes in the postoperative group of patients (All P < 0.05, FDR corrected). Our findings indicate that in HFS, the white matter structural network was disrupted before and after MVD, and that these alterations in the postoperative group were correlated with the clinical outcomes. White matter alteration here described may subserve as potential biomarkers for HFS and may help us identify patients with HFS who can benefit from MVD and thus can help us make a proper surgical patient selection.
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Espasmo Hemifacial , Cirurgia de Descompressão Microvascular , Substância Branca , Humanos , Espasmo Hemifacial/diagnóstico por imagem , Espasmo Hemifacial/cirurgia , Cirurgia de Descompressão Microvascular/métodos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Resultado do Tratamento , Imagem de Difusão por Ressonância Magnética , Estudos RetrospectivosRESUMO
BACKGROUND: Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy has been implemented as a therapeutic alternative for the treatment of drug-refractory essential tremor (ET). However, its impact on the brain structural network is still unclear. PURPOSE: To investigate both global and local alterations of the white matter (WM) connectivity network in ET after MRgFUS thalamotomy. STUDY TYPE: Retrospective. SUBJECTS: Twenty-seven ET patients (61 ± 11 years, 19 males) with MRgFUS thalamotomy and 28 healthy controls (HC) (61 ± 11 years, 20 males) were recruited for comparison. FIELD STRENGTH/SEQUENCE: A 3 T/single shell diffusion tensor imaging by using spin-echo-based echo-planar imaging, three-dimensional T1 weighted imaging by using gradient-echo-based sequence. ASSESSMENT: Patients were undergoing MRgFUS thalamotomy and their clinical data were collected from pre-operation to 6-month post-operation. Network topological metrics, including rich-club organization, small-world, and efficiency properties were calculated. Correlation between the topological metrics and tremor scores in ET groups was also calculated to assess the role of neural remodeling in the brain. STATISTICAL TESTS: Two-sample independent t-tests, chi-squared test, ANOVA, Bonferroni test, and Spearman's correlation. Statistical significance was set at P < 0.05. RESULTS: For ET patients, the strength of rich-club connection and clustering coefficient significantly increased vs. characteristic path length decreased at 6-month post-operation compared with pre-operation. The distribution pattern of rich-club regions was different in ET groups. Specifically, the order of the rich-club regions was changed according to the network degree value after MRgFUS thalamotomy. Moreover, the altered nodal efficiency in the right temporal pole of the superior temporal gyrus (R = 0.434-0.596) and right putamen (R = 0.413-0.436) was positively correlated with different tremor improvement. DATA CONCLUSION: These findings might improve understanding of treatment-induced modulation from a network perspective and may work as an objective marker in the assessment of ET tremor control with MRgFUS thalamotomy. LEVEL OF EVIDENCE: 3 TECHNICAL EFFICACY: Stage 4.
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Tremor Essencial , Substância Branca , Masculino , Humanos , Imagem de Tensor de Difusão , Tremor Essencial/diagnóstico por imagem , Tremor Essencial/cirurgia , Estudos Retrospectivos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Tremor , Tálamo/diagnóstico por imagem , Tálamo/cirurgia , Imageamento por Ressonância Magnética/métodos , Resultado do TratamentoAssuntos
Glioma , Substância Branca , Humanos , Substância Branca/cirurgia , Glioma/cirurgia , Fibras NervosasRESUMO
BACKGROUND AND OBJECTIVES: Anterior temporal lobectomy and amygdalohippocampectomy is a challenging procedure because of the deep surgical trajectory and complex regional neurovascular anatomy. A thorough knowledge of the involved anatomic structures is crucial for a safe and effective procedure. Our objective is to explore the white matter pathways in or around the operative corridor and to illuminate the 3-dimensional relationships of the pertinent operative parenchymal and skull base anatomy, aiming to inform and simplify surgical practice. METHODS: Four normal, adult, cadaveric, formalin-fixed cerebral hemispheres (2 left and 2 right) treated with the Klinger's technique and 2 formalin-fixed and colored-latex-injected cadaveric heads (4 sides) were used. Focused white matter and cadaveric dissections were used to study the relevant anatomy implicated during an anterior temporal lobectomy. Four illustrative cases were also included. Digital photographs from every dissection step were obtained. RESULTS: Major white matter pathways that are inevitably traversed during the approach are the inferior longitudinal fasciculus, uncinate fasciculus, and inferior arm of the cingulum. Tracts that can be potentially injured, should the dissection plane tilt inadvertently superiorly or posteriorly, are the inferior fronto-occipital fasciculus, Meyer's loop, superior longitudinal fasciculus/arcuate fasciculus complex, and basal ganglia. Consistent cranial and parenchymal landmarks that can act as a roadmap during the procedure are recorded and paired with their intraoperative equivalent to provide a thorough, yet simple, stepwise guide for the surgeon. CONCLUSION: White matter dissections, cadaveric cranial dissections, and intraoperative images are put together to provide a simplified stepwise surgical manual for anterior temporal lobectomy. Laboratory investigations that focus on the intricate 3-dimensional relationships of the pertinent operative anatomy from the surgeon's eye may enrich anatomic knowledge and push surgical boundaries, to minimize complication rates and ultimately improve patient outcomes.
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Substância Branca , Adulto , Humanos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Substância Branca/anatomia & histologia , Lobectomia Temporal Anterior , Dissecação , Formaldeído , CadáverRESUMO
BACKGROUND: Two Centuries from today, Karl Friedrich Burdach attributed the nomenclature "arcuate fasciculus" to a white matter (WM) pathway connecting the frontal to the temporal cortices by arching around the Sylvian fissure. Although this label remained essentially unvaried, the concepts related to it and the characterization of the structural properties of this bundle evolved along with the methodological progress of the past years. Concurrently, the functional relevance of the arcuate fasciculus (AF) classically restricted to the linguistic domain has extended to further cognitive abilities. These features make it a relevant structure to consider in a large variety of neurosurgical procedures. OBJECTIVE: Herein, we build on our previous review uncovering the connectivity provided by the Superior Longitudinal System, including the AF, and provide a handy representation of the structural organization of the AF by considering the frequency of defined reports in the literature. By adopting the same approach, we implement an account of which functions are mediated by this WM bundle. We highlight how this information can be transferred to the neurosurgical field by presenting four surgical cases of glioma resection requiring the evaluation of the relationship between the AF and the nearby structures, and the safest approaches to adopt. CONCLUSIONS: Our cumulative overview reports the most common wiring patterns and functional implications to be expected when approaching the study of the AF, while still considering seldom descriptions as an account of interindividual variability. Given its extension and the variety of cortical territories it reaches, the AF is a pivotal structure for different cognitive functions, and thorough understanding of its structural wiring and the functions it mediates is necessary for preserving the patient's cognitive abilities during glioma resection.
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Glioma , Substância Branca , Humanos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Vias Neurais/cirurgia , Córtex Cerebral , Glioma/diagnóstico por imagem , Glioma/cirurgia , Lobo TemporalRESUMO
Peritumoral edema prevents fiber tracking from diffusion tensor imaging (DTI). A free-water correction may overcome this drawback, as illustrated in the case of a patient undergoing awake surgery for brain metastasis. The anatomical plausibility and accuracy of tractography with and without free-water correction were assessed with functional mapping and axono-cortical evoked-potentials (ACEPs) as reference methods. The results suggest a potential synergy between corrected DTI-based tractography and ACEPs to reliably identify and preserve white matter tracts during brain tumor surgery.
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Neoplasias Encefálicas , Substância Branca , Humanos , Imagem de Tensor de Difusão/métodos , Neoplasias Encefálicas/diagnóstico por imagem , Neoplasias Encefálicas/cirurgia , Neoplasias Encefálicas/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Substância Branca/patologia , Vigília , Água , Mapeamento Encefálico/métodos , Encéfalo/patologiaRESUMO
Meningiomas that arise in the atria of the lateral ventricles are relatively rare lesions, that pose a unique challenge for surgery due to their deep-seated location and proximity to critical white matter tracts. Size and anatomical variations can affect the best approach for these tumors, with several approaches described to access the atrium including the interhemispheric trans-precuneus, trans-supramarginal gyrus, distal trans-sylvian, supracerebellar trans-collateral sulcus, and finally the trans-intraparietal sulcus approach, which was the choice for this case. Minimally invasive techniques that preserve the surrounding tissue are becoming increasingly popular and are perfectly suited to deep seated lesions. The relevant subcortical anatomy surrounding the atrium is discussed. The optic radiations form the lateral wall of the atrium, whereas commissural fibers of the tapetum form the roof of the atrium, and superficial to these fibers we have the superior longitudinal fasciculus that have vertical rami that communicate with the superior parietal lobule. Utilizing the posterior half of the intraparietal sulcus can preserve these fibers. The use of neuronavigation, brain magnetic resonance imaging with diffusion tensor imaging (DTI) tractography may be helpful in the surgical planning. In this article, we present a surgical video of a trans-tubular interparietal sulcus approach for resection of an atrium meningioma. A 43-year-old right-handed female who presented with progressive headaches and a diagnosis of idiopathic intracranial hypertension was found to have an atrial meningioma that grew in follow-up and surgery was recommended. We chose the posterior intraparietal sulcus approach as it provides a good angle of attack while preserving the optic radiations and most of the superior longitudinal fasciculus, using a tubular retractor to minimize tissue damage. Gross total resection of the tumor was achieved with complete preservation of patient neurological function.
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Neoplasias Meníngeas , Meningioma , Substância Branca , Humanos , Feminino , Adulto , Imagem de Tensor de Difusão , Meningioma/diagnóstico por imagem , Meningioma/cirurgia , Lobo Parietal/diagnóstico por imagem , Lobo Parietal/cirurgia , Imageamento por Ressonância Magnética , Substância Branca/cirurgia , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/cirurgiaRESUMO
ABTRACT: The dichotomy of the cingulum bundle into the dorsal supracallosal and ventral parahippocampal parts is widely accepted; however, the retrosplenial component with its multiple alternative connections has not been revealed. The aim of this study was to delineate the microsurgical anatomy of a connectionally transition zone, the isthmic cingulum, in relation to the posteromedial interhemispheric access to the atrium and discuss the relevant patterns of glioma invasion on the basis of its fiber connections. White matter (WM) fibers were dissected layer by layer in a medial-to-lateral, lateral-to-medial, and posterior-to-anterior fashion. All related tracts and their connections were generated using deterministic tractography. The magnetic resonance imaging (MRI) tractography findings were correlated with those of fiber dissection. A medial parieto-occipital approach to reach the atrium was performed with special emphasis on the cingulate isthmus and underlying WM connections. The isthmic cingulum, introduced as a retrosplenial connectional crossroad for the first time, displayed multiple connections to the splenium and the superior thalamic radiations. Another new finding was the demonstration of lateral hemispheric extension of the isthmic cingulum fibers through the base of the posterior part of the precuneus at the base of the parieto-occipital sulcus. The laterally crossing cingulum fibers were interconnected with three distinct association tracts: the middle longitudinal (MdLF), the inferior frontooccipital fasciculi (IFOF), and the claustro-cortical fibers (CCF). In the process of entry to the atrium during posterior interhemispheric approaches, the splenial and thalamic connections, as well as the laterally crossing fibers of the isthmic cingulum, were all in jeopardy. The connectional anatomy of the retrosplenial area is much more complicated than previously known. The isthmic cingulum connections may explain the concept of interhemispheric and medial to lateral cerebral hemisphere invasion patterns in medial parieto-occipital and posteromesial temporal gliomas. The isthmic cingulum is of key importance in posteromedial interhemispheric approaches to both: the atrium and the posterior mesial temporal lobe.
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Cérebro , Glioma , Substância Branca , Humanos , Substância Branca/cirurgia , Substância Branca/patologia , Cérebro/anatomia & histologia , Cérebro/cirurgia , Córtex Cerebral , Lobo Parietal , Glioma/cirurgia , Glioma/patologia , Vias Neurais/cirurgiaRESUMO
Despite being associated with high-order neurocognitive functions, the frontal lobe plays an important role in core neurological functions, such as motor and language functions. The aim of this study was to present a neurosurgical perspective of the cortical and subcortical anatomy of the frontal lobe in terms of surgical treatment of intraaxial frontal lobe lesions. We also discuss the results of direct brain mapping when awake craniotomy is performed. Ten adult cerebral hemispheres were prepared for white matter dissection according to the Klingler technique. Intraaxial frontal lobe lesions are approached with a superior or lateral trajectory during awake conditions. The highly eloquent cortex within the frontal lobe is identified within the inferior frontal gyrus (IFG) and precentral gyrus. The trajectory of the approach is mainly related to the position of the lesion in relation to the arcuate fascicle/superior longitudinal fascicle complex and ventricular system. Knowledge of the cortical and subcortical anatomy and its function within the frontal lobe is essential for preoperative planning and predicting the risk of immediate and long-term postoperative deficits. This allows surgeons to properly set the extent of the resection and type of approach during preoperative planning.
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Neoplasias Encefálicas , Córtex Motor , Substância Branca , Adulto , Humanos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Substância Branca/anatomia & histologia , Neoplasias Encefálicas/patologia , Lobo Frontal/diagnóstico por imagem , Lobo Frontal/cirurgia , Lobo Frontal/anatomia & histologia , Mapeamento Encefálico/métodos , IdiomaRESUMO
While there is strong evidence from lesion and functional imaging studies implicating the left anterior temporal pole (LTP) in naming unique entities, less is known about white matter tracts in category-specific naming. We present evidence that implicates the uncinate fasciculus (UF) in proper noun naming. First, we describe two patients with left LTP gliomas who developed category specific worsening in proper noun naming in real time during awake surgery when the UF was surgically involved . We then describe a third case involving targeted electrical stimulation of the UF using stereo-electroencephalography (sEEG) that resulted in category specific naming disturbance for proper nouns..
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Neoplasias Encefálicas , Substância Branca , Humanos , Neoplasias Encefálicas/patologia , Fascículo Uncinado/patologia , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Substância Branca/patologia , Vigília , Eletroencefalografia , Estimulação ElétricaRESUMO
Purpose: White-matter tract segmentation in patients with brain pathology can guide surgical planning and can be used for tissue integrity assessment. Recently, TractSeg was proposed for automatic tract segmentation in healthy subjects. The aim of this study was to assess the use of TractSeg for corticospinal-tract (CST) segmentation in a large cohort of patients with brain pathology and to evaluate its consistency in repeated measurements. Methods: A total of 649 diffusion-tensor-imaging scans were included, of them: 625 patients and 24 scans from 12 healthy controls (scanned twice for consistency assessment). Manual CST labeling was performed in all cases, and by 2 raters for the healthy subjects. Segmentation results were evaluated based on the Dice score. In order to evaluate consistency in repeated measurements, volume, Fractional Anisotropy (FA), and Mean Diffusivity (MD) values were extracted and correlated for the manual versus automatic methods. Results: For the automatic CST segmentation Dice scores of 0.63 and 0.64 for the training and testing datasets were obtained. Higher consistency between measurements was detected for the automatic segmentation, with between measurements correlations of volume = 0.92/0.65, MD = 0.94/0.75 for the automatic versus manual segmentation. Conclusions: The TractSeg method enables automatic CST segmentation in patients with brain pathology. Superior measurements consistency was detected for the automatic in comparison to manual fiber segmentation, which indicates an advantage when using this method for clinical and longitudinal studies.
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Imagem de Tensor de Difusão , Tratos Piramidais , Substância Branca , Humanos , Imagem de Tensor de Difusão/métodos , Tratos Piramidais/diagnóstico por imagem , Tratos Piramidais/patologia , Tratos Piramidais/cirurgia , Substância Branca/diagnóstico por imagem , Substância Branca/patologia , Substância Branca/cirurgia , Estudos de Casos e Controles , Reprodutibilidade dos TestesRESUMO
BACKGROUND: Klinger's fiber dissection technique is widely used for studying the anatomy of white matter. Herein, we present a technical description of Klinger's proposed fiber dissection algorithm with neuronavigation assistance which allows for a more accurate determination of the projection of association fibers. METHODS: An anatomical study was conducted on 8 hemispheres of the human brain, prepared according to the Klingler fiber dissection technique. In all the cases, a frameless electromagnetic navigation system was used. For each anatomical specimen, an individualized support device was three-dimensional -printed and placed it into the magnetic resonance imaging (MRI) gantry. MRI study of each anatomical specimen was performed using a specific protocol that enabled a subsequent three-dimensional visualization of the anatomical structures as follows: FSPGR (Fast SPoiled Gradient Recalled echo) BRAVO (BRAin VOlume Imaging), T2 CUBE, FLAIR (FLuid Attenuated Inversion Recovery) CUBE, CUBE DIR (double inversion recovery) WHITE MATTER, and CUBE DIR GRAY MATTER. RESULTS: The average time required to register an anatomical specimen in the navigation system was 7 minutes 28 seconds. In all of the 8 cases, the anatomical structures were correctly identified using neuronavigation. Moreover, the choice of MRI mode depends on the purpose of the study and the region of interest in the brain. CONCLUSIONS: Electromagnetic navigation is an accurate and useful technique. It allows the researcher the ability to virtually project the association fibers and their cortico-cortical terminations to the surface of the brain, even at the final stages of dissection when the superficial structures are removed. To obtain accurate targeting, it is important to use the appropriate neuronavigation protocol.
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Neuronavegação , Substância Branca , Humanos , Neuronavegação/métodos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Substância Branca/anatomia & histologia , Encéfalo/diagnóstico por imagem , Encéfalo/cirurgia , Encéfalo/anatomia & histologia , Imageamento por Ressonância Magnética/métodos , Fenômenos EletromagnéticosRESUMO
BACKGROUND: The understanding of white matter (WM) was revolutionized by the emergence of tractography based on diffusion tensor imaging (DTI). Currently, DTI simulations are implemented in preoperative planning to optimize surgical approaches. The reliability of these simulations has been questioned and investigated seeking for correlation between neurological performance and anomalies in DTI parameters. However, the ability of preoperative WM simulations to predict a surgical injury has not been thoroughly evaluated. Our objective was to assess the reliability of preoperatively simulated WM injuries for conventional neurosurgical procedures. METHODS: WM surgical damage was preoperatively simulated by creating a 3-dimensional volume representing the endoscope or the surgical trajectory. This volume was used as an additional region of interest in the fascicle reconstruction to be subtracted from the original fascicle. Simulated, injured fascicles were compared in terms of the number of fibers and volume to those created from postoperative DTI studies. Reliability was assimilated into the correlation between the simulation and the postoperative reconstruction; evaluated using the intraclass correlation coefficient or Lin's Concordance correlation coefficient (CCC), and represented on Bland-Altman plots. RESULTS: The preoperative and postoperative DTI studies of 30 patients undergoing various neurosurgical approaches were processed. The correlation between simulated injuries and postoperative studies was high in terms of fibers (Concordance correlation coefficient = Rho.C = 0.989 [95% confidence interval = 0.979-0.995]) and volume (intraclass correlation coefficient = 0.95 [95% CI = 0.89-0.97]). Bland-Altman plots demonstrated that the great majority of cases fell within the mean ± 2 Standard deviations. CONCLUSIONS: Presurgical simulation of WM fascicles based on DTI is consistent with postoperative DTI studies. These findings require further validation by neurophysiological and clinical correlation.
Assuntos
Lesões Encefálicas , Substância Branca , Humanos , Imagem de Tensor de Difusão/métodos , Substância Branca/diagnóstico por imagem , Substância Branca/cirurgia , Reprodutibilidade dos Testes , Procedimentos NeurocirúrgicosRESUMO
Secondary to the creation of a surgical corridor and retraction, white matter tracts degenerate, causing long-term scarring with potential neurological consequences. Third and lateral ventricle tumors require surgery that may lead to cognitive impairment. Our objective is to compare the long-term consequences of a transcortical transfrontal approach and an interhemispheric transcallosal approach on corpus callosum and frontal white matter tracts degeneration. Surgical patients with ventricular tumor accessible through both approaches were included and clinico-radiological data were retrospectively analyzed. The primary endpoint was the callosotomy length at 3-month post-operative T1 MRI, corrected by the extension of the tumor and the use of neuronavigation. Secondary outcomes included perioperative criteria such as bleeding, use of retractors and duration, FLAIR hypersignal on 3-month MRI, and re-do surgeries. To assess white matter tract interruption, 3-month FLAIR hypersignal was superposed to a tractography atlas. Seventy patients were included, 57 (81%) in the transfrontal group and 13 (19%) in the interhemispheric group. There was no difference in the mean callosotomy length on 3-month MRI (12.3 mm ± 5.60 transfrontal vs 11.7 mm ± 3.92 interhemispheric, p = 0.79) on univariate and multivariate analyses. The callosotomy length was inferior by - 3.13 mm for tumors located exclusively in the third ventricle (p = 0.016), independent of the approach. Retractors were used more often in transfrontal approaches (60% vs 33%, p < 0.001). The extent of frontal FLAIR hypersignal was higher after transfrontal approach (14.1 mm vs 0.525 mm, p < 0.001), correlated to the use of retractors (p < 0.05). After the interhemispheric approach, no tract other than corpus callosum was interrupted, whereas, after the transfrontal approach, frontal arcuate fibers and projections from the thalamus were interrupted in all patients, the cingulum in 19 (33%), the superior fronto-occipital fasciculus in 15 (26%), and the superior longitudinal fasciculus in 2 (3%). Transfrontal and interhemispheric approaches to the third and lateral ventricles both lead to the same long-term damage to the corpus callosum, but the transfrontal approach interrupts several white matter tracts essential to cognitive tasks such as attention and planning, even in the non-dominant hemisphere. These results encourage all neurosurgeons to be familiar with both approaches and favor the interhemispheric approach when both can give access to the tumor with a comparable risk. Neuropsychological studies are necessary to correlate these anatomical findings to cognitive outcomes.