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

Microbeam radiation therapy is a novel preclinical technique, which uses synchrotron-generated X-rays for the treatment of brain tumours and drug-resistant epilepsies. In order to safely translate this approach to humans, a more in-depth knowledge of the long-term radiobiology of microbeams in healthy tissues is required. We report here the result of the characterization of the rat sensorimotor cortex tolerance to microradiosurgical parallel transections. Healthy adult male Wistar rats underwent irradiation with arrays of parallel microbeams. Beam thickness, spacing and incident dose were 100 or 600 µm, 400 or 1200 µm and 360 or 150 Gy, respectively. Motor performance was carried over a 3-month period. Three months after irradiation rats were sacrificed to evaluate the effects of irradiation on brain tissues by histology and immunohistochemistry. Microbeam irradiation of sensorimotor cortex did not affect weight gain and motor performance. No gross signs of paralysis or paresis were also observed. The cortical architecture was not altered, despite the presence of cell death along the irradiation path. Reactive gliosis was evident in the microbeam path of rats irradiated with 150 Gy, whereas no increase was observed in rats irradiated with 360 Gy.

Objective The supplementary motor area (SMA) is important for the prediction of post-operative symptoms after surgical resection of gliomas. We investigated the relationships between clinical factors and the resection range of SMA gliomas, and the post-operative neurological symptoms. Methods We retrospectively studied 18 consecutive surgeries for gliomas involving the SMA proper performed in 13 patients. Seven cases were recurrence of the tumour. Clinical factors and details of specific resection of the SMA proper (resection of posterior part, medial wall) and cingulate motor area (CMA) were examined. Results Eight cases suffered new post-operative neurological deficits. Six of these eight cases had transient deficits. Permanent deficits persisted in two cases with partial weakness or paresis, after rapid improvement of post-operative global weakness or hemiplegia, respectively. The risk of post-operative neurological deficits was not associated with the resection of the posterior part of the SMA proper or the CMA, but was associated with resection of the medial wall of the SMA proper. Surgery for recurrent tumour was associated with post-operative neurological deficits. The medial wall was frequently resected in recurrent cases. Discussion The frequency of post-operative neurological symptoms, including SMA syndrome, may be higher after resection of the medial wall of the SMA proper compared with the resection of only the lateral surface of the SMA proper.

Angiocentric gliomas have recently been reclassified as a separate central nervous system tumor. Few cases have been reported, and most of those correspond to slow-growing, low-grade neoplasms in very young pediatric patients. Here we describe magnetic resonance imaging findings (including diffusion imaging, spectroscopy and tractography) in an unusual higher-grade neoplasm with pathologic features suggestive of an angiocentric glioma in a 15-year-old male. The tumor had mild heterogeneous enhancement on magnetic resonance imaging, and a low apparent diffusion coefficient (9.9 × 10(-4) mm(2)s(-1)), consistent with an intermediate-to-high cellularity tumor. Spectroscopic imaging showed elevated choline/phosphocreatine and choline/N-acetyl aspartate ratios, suggesting an unusually aggressive tumor. We conclude that angiocentric glioma should not be excluded from consideration at primary diagnosis, particularly in teenaged patients nearing adulthood.

We aimed to describe a single institution experience of neuroimaging failure to demonstrate malignant primary brain tumors. We retrospectively reviewed case histories for all newly diagnosed adult patients with malignant primary brain tumors treated at a single institution between 1 July 2006 and 30 June 2008. We specifically looked at patients in whom neuroimaging was normal or non-diagnostic at initial presentation. Among 193 patients with malignant primary brain tumors, there were 102 with World Health Organization (WHO) grade IV gliomas (glioblastoma multiforme, GBM), 54 with anaplastic gliomas, 18 with low grade gliomas, and 19 with primary central nervous system lymphomas (PCNSL). Initial imaging was normal in nine patients and abnormal but non-diagnostic in an additional eight patients with primary brain cancer. Normal or non-diagnostic neuroimaging was not uncommon among patients with GBM. Dramatic, rapid tumor growth is possible. Close interval clinical and radiographic follow-up can be important especially in the management of elderly patients presenting with seizures and non-diagnostic neuroimaging studies., (Copyright © 2011 Elsevier Ltd. All rights reserved.)

Objective: Test the hypothesis about the potential role of functional MRI (fMRI) to evaluate the plasticity of the cortical motor areas in patients with brains tumors and brain arteriovenous malformations (AVMs) and measurement of the lesion-to-fMRI activation distance for predicting risk of new motor deficit after surgery., Material and Method: This was a retrospective study. The present study population enrolled eight patients with motor cortex lesions. Cortical motor representations were mapped in these patients harboring tumor or AVMs occupying the region of primary motor cortex (M1). Five patients had known diagnosis of primary brain tumor including glioblastoma multiforme, (n = 1), diffuse astrocytoma (n = 2), dysembryoplastic neuroepithelial tumor (DNET) (n = 1) and unknown pathology (n = 1). Three patients had known diagnosis of brain AVMs. Three patients showed hemiparesis at the time of presentation. Focal/generalized seizure or headache was present in the remaining patients. Simple movements of both hands were performed Localization of the activation in the affected hemisphere was compared with that in the unaffected hemisphere and evaluated with respect to the normal M1 somatotopic organization. Distance between the location of the fMRI activation (M1) and margin of the lesion was recorded., Results: Cortical activation was found in two patterns: 1) functional displacement within affected M1 independent of the structural distortion induced by the tumor or AVMs (n = 7) and 2) presence of activation within the non-primary motor cortex without activation in the affected or unaffected M1 (n = 1)., Conclusion: Brain tumor or AVMs led to reorganization within the somatotopic affected M1 and can expand into non-primary motor cortex area. Distortion of the anatomy alone by the space-taking lesion did not influence the location of the reorganized cortex. No particular type of reorganization pattern could be predicted fMRI could be localized reorganized cortex and was found to be a useful tool to assess the lesion-to-activation distance for predicting risk of new motor deficit after surgery. The present study thus emphasizes the importance of considering additional fMRI with structural MRI to evaluate individual differences in cortical plasticity for treatment planning, particularly in the neurosurgical procedure.

Purpose: The purpose of this study is to provide longitudinal data on neurological and neuropsychological restitution following resection of an extra-axial space-occupying lesion., Case Report: A comprehensive neuropsychological test battery was utilised preoperatively and 1, 4, 11, and 24 months, respectively, after removal of a parasagittal meningioma compressing the right frontal lobe in a right-handed 6-year-old boy with average intelligence., Results: Symptoms related to brain compression (left-sided hemiparesis, diplopia) resolved shortly after surgery. Recovery of specific cognitive functions (short- and long-term memory, attention, and dichotic listening performance) was more protracted., Conclusion: Here, we illustrate the potential of a structured follow-up analysis, based on neuropsychological testing. We were able to distinguish separate time-courses for neurological functions but even more distinct within complex neuropsychological processes. This time-dependent recovery should be considered when designing longitudinal follow-up studies.

We report a 65 year old man who presented with left hemiparesis, and was found to have multiple, discrete, peripherally enhancing, hemorrhagic intra-axial masses in the right hemisphere of the brain. Workup for malignancy elsewhere in the body was negative, and biopsy confirmed glioblastoma multiforme. The patient responded clinically to treatment with radiation therapy and temozolomide. We discuss the unusual aspects of this case and stress the importance of tissue diagnosis in managing suspected intracranial malignancies.

Background and Purpose: The underlying changes in the neuronal connectivity adjacent to brain tumors cannot always be depicted by conventional MR imaging. The hypothesis of this study was that preoperative sensorimotor deficits are associated with impairment in pyramidal fiber bundles. Hence, we investigated the potential of combined quantitative diffusion tensor (DT) fiber tracking and MR spectroscopic imaging (MRSI) to determine changes in the pyramidal tract adjacent to gliomas., Materials and Methods: Quantitative DT fiber tracking and proton MRSI were performed in 20 patients with gliomas with WHO grades II-IV. Eight patients experienced preoperative sensorimotor deficits. Mean diffusivity (MD), fractional anisotropy (FA), and number of fibers per voxel (FpV) were calculated for the pyramidal tract of the ipsilateral and contralateral hemisphere. Metabolite concentrations for choline-containing compounds (Cho), creatine (Cr), and N-acetylaspartate (NAA) were computed, using LCModel, for all voxels located at the pyramidal tracts., Results: For the whole pyramidal tract, quantitative DT fiber tracking resulted in significantly lower FpV and FA values (P < .001), but not MD values, for the ipsilateral hemisphere. For the section of the fiber bundle closest to the lesion, we found significantly decreased FpV and FA (P < .001) and increased MD (P = .002). MRSI showed, for the same volumes of interest, significantly decreased NAA (P = .001), increased Cho (P = .034) and Cho/NAA (P = .001) for the ipsilateral pyramidal tract. In patients suffering sensorimotor deficits, we found significantly lower FA (P = .022) and higher MD values (P = .026) and a strongly negative correlation between FA and MD (R = -0.710, P = .024) but no correlation in patients without deficits (R = 0.078, ns)., Conclusion: Quantitative DTI was able to show significant differences in diffusivity of the pyramidal tract in patients with sensorimotor deficits in relation to patients without them. The additional use of proton MRSI may be helpful to discern whether these diffusivity changes in fiber tracts are caused by tumor infiltration or peritumoral edema.

Focal areas of restricted diffusion adjacent to high-grade glioma resection cavities were detected in 70% of patients on immediate postoperative MRI studies. Follow-up studies demonstrated cystic encephalomalacia in 91% of these foci, suggesting the presence of infarction, and the infarcted tissue demonstrated enhancement in 43% of cases. New postoperative deficits correlated well with the anatomic region of infarction in six patients. Enhancement in perioperative infarcts can mimic tumor progression on follow-up imaging studies.

(1)H magnetic resonance spectroscopic imaging (MRSI) was performed on a patient with an admission diagnosis of recurrent astrocytoma. The patient had undergone surgical resection and radiation therapy for a left occipital astrocytoma WHO grade III 12 years previously, and presented with aphasia, right-sided hemiparesis, and severe headache. Postcontrast T1-weighted images showed cortical enhancement of the left parietotemporal lobe near the post-resection cavity. MRSI revealed a marked increase of trimethylamines (TMA), elevated creatine/creatinephosphate (tCr), and reduced N-acetyl-aspartate (tNAA) in the same brain region. The spectroscopic data were consistent with tumor recurrence. However, the pattern of contrast enhancement on magnetic resonance imaging (MRI), evidence of an epileptic focus on electroencephalography (EEG), and spontaneous regression of the symptoms argued against tumor recurrence. In a 4-week follow-up, the contrast enhancement disappeared on MRI and the EEG abnormalities and neurological symptoms resolved. Follow-up spectroscopic data showed a decrease in TMA compared to normal values. The tCr signal remained elevated but returned to normal values after 5 months. In conclusion, postictal neurological deficits with a temporary increase in TMA and tCr were diagnosed. This is the first report of seizure-induced MRS abnormalities mimicking tumor recurrence., ((c) 2006 Wiley-Liss, Inc.)

A 7-year-old boy presented with headache, visual disturbance, and psychomotor seizures persisting for 7 months. He had mild hemiparesis and homonymous hemianopia on the left. Neuroimaging showed bilateral temporal lobe masses with calcification and cysts. The right temporal mass was subtotally resected. The histological diagnosis was pilocytic astrocytoma with ependymal differentiation and a MIB-1 staining index of up to 8.0%. Postoperatively his hemiparesis and psychomotor seizures disappeared. Adjuvant chemotherapy consisting of carboplatin and vincristine was given followed by radiotherapy. Neuroimaging showed that the bilateral tumors had disappeared and showed no recurrence for 29 months after the diagnosis. Pilocytic astrocytoma usually presents as a solitary mass in the cerebellum or optic pathway with low proliferative activity, but should be included in the differential diagnosis of multifocal tumors arising in the bilateral temporal lobes. Ependymal differentiation with extremely high proliferative activity might be related to this unusual clinical presentation. Intensive treatment is recommended for patients with such specific neuroimaging and histological features.

A case of extraventricular neurocytoma with spontaneous intratumoral hemorrhage is reported. A 47-year-old man presented with sudden left-sided hemiparesis. Magnetic resonance imaging revealed a right parietal subcortical mass with intratumoral hemorrhagic transformation and without contact to the ventricular system. After complete microsurgical removal, the tumor was histologically diagnosed as neurocytoma. Usually, the term "central neurocytoma" is restricted to neurocytic neoplasms arising within the cerebral ventricles. In the majority of the cases, these slow-growing, generally circumscribed lesions become symptomatic by obstructive hydrocephalus. Hemorrhagic onset is sporadically reported in the literature. In contrast to central neurocytomas, neurocytic lesions located within the brain parenchyma, so-called "extraventricular neurocytomas" are very uncommon. To the knowledge of the authors, this is the first case of an extraventricular neurocytoma with histological classic features presenting with intratumoral hemorrhage in adults.

Background: Functional MRI (fMRI) combines anatomic with functional information and has therefore been widely used for preoperative planning of patients with mass lesions affecting functionally important brain regions. However, the courses of functionally important fiber tracts are not visualized. We therefore propose to combine fMRI with diffusion-weighted MRI (DWI) that allows visualization of large fiber tracts and to implement this data in a neuronavigation system., Methods: DWI was successfully performed at a field strength of 1.5 Tesla, employing a spin-echo sequence with gradient sensitivity in six noncollinear directions to visualize the course of the pyramidal tracts, and was combined with echo-planar T2* fMRI during a hand motor task in a patient with central cavernoma., Results: Fusion of both data sets allowed visualization of the displacement of both the primary sensorimotor area (M1) and its large descending fiber tracts. Intraoperatively, these data were used to aid in neuronavigation. Confirmation was obtained by intraoperative electrical stimulation. Postoperative MRI revealed an undisrupted pyramidal tract in the neurologically intact patient., Conclusion: The combination of fMRI with DWI allows for assessment of functionally important cortical areas and additional visualization of large fiber tracts. Information about the orientation of fiber tracts in normal appearing white matter in patients with tumors within the cortical motor system cannot be obtained by other functional or conventional imaging methods and is vital for reducing operative morbidity as the information about functional cortex. This technique might, therefore, have the prospect of guiding neurosurgical interventions, especially when linked to a neuronavigation system.

Introduction: Thalamic tumors (TTs) account for approximately 1% of all intracranial neoplasms. TTs are seen predominantly in children and young adults. Most childhood neoplasms in this location are of glial lineage, a large proportion being low-grade tumors. The evolution of symptoms before diagnosis is characteristically shorter in children than in adults., Clinical Presentation: Clinical features of TTs reflect the pressure of the mass on the cerebrospinal fluid pathways, the pyramidal tracts, the thalamic nuclei and the optic radiations. In this paper, we review the clinical data of 20 children with TTs seen at our hospital and compare the findings with those in the current literature. An acute presentation is not rare and was encountered in 20% of our patients, although most individuals had a subacute or slow evolution. Symptoms and signs of raised intracranial pressure (65%), motor deficits (40%), and seizures (35%), alone or in combination, were the most frequent manifestations of TTs. Behavioral and mental changes are not uncommon in TTs and were found in 25% of our patients. Involuntary movements (10%) and the classic thalamic syndrome (5%) were quite exceptional. Infants and young children with TTs may present with macrocephaly, psychomotor delay, and failing vision or disorders of ocular movements.

Objective: To demonstrate whether cortical activation within different cortical motor regions in neurosurgical patients varies with the degree of paresis induced by mass lesions near the central region., Methods: A total of 110 patients with brain tumors infiltrating the central region and with varying degrees of paresis were investigated employing fMRI during the performance of hand motor tasks. The percent signal change between rest and activation was calculated for four cortical regions: primary motor cortex (M1), supplementary motor area, premotor area, and superior parietal lobule., Results: Significant decreases in activation with increasing degrees of paresis were found in M1, whereas significant increases in activation were noted in secondary motor areas that were not affected by the tumor., Conclusions: The signal loss in areas adjacent to tumor tissue may relate either to tumor-induced changes in cerebral hemodynamics or to a direct loss of cortical neurons resulting in a lesser degree of hemodynamic changes after motor activation. The increase in activation within secondary motor areas with increasing degrees of paresis supports the growing evidence of a practice- and lesion-dependent reorganization of the cortical motor system and the ability of the brain to modulate its excitatory output according to external demands.

A case of brain surface ependymoma is reported here. A 41-year-old woman presented with weakness of the right upper limb. Magnetic resonance imaging revealed a left fronto-parietal cystic tumor with a calcified mural nodule. Total removal of the tumor was performed. This tumor was located within the surface portion of the fronto-parietal parenchyma and was sharply demarcated from the surrounding brain tissue, and there was no continuity with the ventricles. Histological examination of this tumor showed monotonous proliferation of tumor cells with moderate cellularity and occasional mitoses, forming true ependymal rosettes and perivascular pseudorosettes with fibrillary background. A clear cell component resembling oligodendroglioma was partly noted. The tumor cells showed positive immunoreaction for glial fibrillary acid protein and vimentin.

Objective: To support the hypothesis about the potential compensatory role of ipsilateral corticofugal pathways when the contralateral pathways are impaired by brain tumours., Methods: Retrospective analysis was carried out on the results of functional MRI (fMRI) of a selected group of five paretic patients with Rolandic brain tumours who exhibited an abnormally high ipsilateral/contralateral ratio of activation-that is, movements of the paretic hand activated predominately the ipsilateral cortex. Brain activation was achieved with a flexion extension of the fingers. Statistical parametric activation was obtained using a t test and a threshold of p<0.001. These patients, candidates for tumour resection, also underwent cortical intraoperative stimulation that was correlated to the fMRI spatial data using three dimensional reconstructions of the brain. Three patients also had postoperative control fMRI., Results: The absence of fMRI activation of the primary sensorimotor cortex normally innervating the paretic hand for the threshold chosen, was correlated with completely negative cortical responses of the cortical hand area during the operation. The preoperative fMRI activation of these patients predominantly found in the ipsilateral frontal and primary sensorimotor cortices could be related to the residual ipsilateral hand function. Postoperatively, the fMRI activation returned to more classic patterns of activation, reflecting the consequences of therapy., Conclusion: In paretic patients with brain tumours, ipsilateral control could be implicated in the residual hand function, when the normal primary pathways are impaired. The possibility that functional tissue still remains in the peritumorous sensorimotor cortex even when the preoperative fMRI and the cortical intraoperative stimulations are negative, should be taken into account when planning the tumour resection and during the operation.