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76. Jahrestagung der Deutschen Gesellschaft für Neurochirurgie

Dr. med.

Vorsitz | Chair

PD Dr.

PD. Dr. med.

The spatial distribution of histologic subtypes of meningioma aligns with genetic alteration maps: a voxel-based lesion mapping study

Neuroonkologie

Die räumliche Verteilung histologischer Subtypen von Meningeomen stimmt mit genetischen Veränderungskarten überein: eine voxelbasierte Läsionskartierungsstudie.

Meningiomas are traditionally classified according to their histologic appearance. There is increasing evidence that meningioma tumorigenesis is associated with genetic alterations in specific gene pathways. Notably, meningiomas linked to similar pathogenic variants show a regional propensity. The correlation between these mutation maps and the spatial distribution of histologic subtypes of meningiomas, however, is still not clarified. The present study aims to determine the spatial profile of the dural attachment zone (DAZ) of different meningioma subtypes.Clinical details (e.g. sex), histological features (e.g. meningioma subtypes, WHO grading) and magnetic resonance images features were obtained in 580 treatment-naïve meningioma patients. MR images were normalized to the standardized MNI52 brain template. After semi-automatic tumor segmentation, the DAZ was determined by intersecting the tumor mask with a dura/falx template. Voxel-based lesion mapping (VLSM) was applied to determine the spatial DAZ profile of different meningioma subtypes and WHO grades.Significant distribution cluster were detected for meningothelial (middle anterior skull base), fibrous/transitional/psammomatous (cerebellar convexity and falx), chordoid (anterior falx), secretory (middle and lateral skull base) and atypic (frontal convexity). WHO grade II meningiomas were clustered at frontal convexity/falx. These patterns aligned with known mutation maps of Hedgehog (meningothelial), NF2 (fibrous/psammomatous/transitional/atypic, high-grade) and SMARCB1 mutations (chordoid).The present study provides first-time an unbiased, voxel-based description of the spatial profiling of histologic subtypes mimicking the known regional propensity of gene alterations found in meningioma tumorigenesis. This study shows the potential of VLSM in neurooncological research.

Abstractvortrag | Abstract talk

Prof. Dr.

Prof. Dr. med.

PD Dr. med.

The frontoparietal condition-and-perturb approach improves preoperative nTMS mapping in patients with language-eloquent tumors.

Technik und Innovation

Der frontoparietale Condition-and-Peturb Ansatz verbessert das präoperative nTMS Mapping bei spracheloquenten Hirntumoren.

The use of preoperative navigated transcranial magnetic stimulation (nTMS) is becoming increasingly common in patients undergoing eloquent brain tumor surgery. Yet the optimal stimulation paradigms for language mapping still lack specificity and need to be refined. This study aims to evaluate the added value of the condition-and-perturb approach (CAP) to preoperative language mapping in non-aphasic patients with language-eloquent brain tumors involving the anterior inferior frontal (aIFG) or angular (AG) gyrus.Patients underwent peritumoral online nTMS involving the affected node (AG or aIFG) with or without prior offline neuronavigated repetitive TMS (nrTMS, 1 Hz, 15 min) of the ipsilateral healthy node (aIFG or AG).8 patients underwent the full protocol. Offline nrTMS decreased error threshold of online language mapping in all patients in comparison to sham nrTMS in those patients. 4 peritumoral language hotspots [2-5] could be isolated in each patient. Compared to direct cortical stimulation, nTMS language mapping with CAP achieved a sensitivity of 84.2%, a specificity of 98.3%, a PPV of 84.2% and an NPV of 98.3%. This means that nearly all CAP-nTMS hotspots induced language disturbances when stimulated intraoperatively with DCS.This pilot study suggests that the CAP could be a possible solution to the specificity concerns of preoperative TMS mapping, as prior frontoparietal network disruption might enhance the precision of language mapping around semantically eloquent brain tumors.

The Effects of Repetitive Transcranial Magnetic Stimulation on Language Performance and Brain Connectivity in Healthy Subjects

Die Auswirkungen repetitiver transkranieller Magnetstimulation auf die Sprachleistung und Gehirnkonnektivität bei gesunden Probanden

This study investigates the effects of combining high-frequency rTMS (HF-rTMS) to the left superior posterior temporal gyrus (spTG) and low-frequency rTMS (LF-rTMS) to the contralateral homologue on language performance, functional connectivity and white matter integrity in healthy individuals. The aim is to validate a dual hemisphere rTMS protocol in healthy individuals to enhance language processing and connectivity within the language network's arcuate fasciculus (AF), with potential applications in post-surgical aphasia treatment.Thirty healthy participants (aged 18-65) are randomized into a treatment group (n = 15), receiving dual hemisphere rTMS, or a sham group (n = 15), following the same procedure with a plastic adapter, ensuring no active brain stimulation. The rTMS protocol includes sequential LF-rTMS at 1 Hz to the right sPTG and HF-rTMS at 10 Hz to the left homologous region, guided by tractography of the AF. Sessions are conducted daily over seven consecutive days, lasting about 18 minutes, during which participants additionally engage in language training exercises. Language performance is assessed pre- and post-intervention, measuring semantic correctness, reaction time, and fluency. Resting-state functional Magnetic Resonance Imaging evaluates functional connectivity, focusing on the language network via correlation coefficients and graph metrics. Structural changes in AF white matter integrity are measured by differences in mean fractional anisotropy values using diffusion-weighted imaging.We found significant improvement in language measures in the treatment group compared to sham. Semantic correctness increased from 93.5% to 96.4% (p = 0.004), reaction times decreased from 3.97 to 3.75 seconds (p = 0.006), and fluency rose from 38.5 to 48.5 words (p = 0.002). Functional connectivity analysis revealed increased global efficiency within the left inferior frontal gyrus (β = 0.09, p-FDR = 0.035), highlighting enhanced language network connectivity.This study provides evidence that a dual hemisphere rTMS approach enhances language performance and modulates functional connectivity in healthy individuals. Significant improvements in semantic correctness, reaction time, fluency, and left inferior frontal gyrus connectivity suggest that rTMS can optimize language-related neural processes, offering insights for clinical applications in aphasia treatment.

Prof.

rTMS-based neuromodulation for treatment of postoperative aphasia after tumor resection – a pilot study

Behandlung postoperativer Sprachstörungen nach Hirntumorresektion mittels rTMS – eine Pilotstudie

Postoperative aphasia is a serious complication after brain tumor resection which can occur despite monitoring during awake craniotomies. In addition to a considerable impairment of the quality of life, the oncological prognosis in these patients is also limited. The neuromodulatory application of rTMS is already established in the treatment of stroke-related aphasia. The aim of this study is to investigate the feasibility of rTMS-based neuromodulation to patients with postoperative aphasia after brain tumor resection.This pilot study includes patients with new or worsening aphasia after brain tumor resection. rTMS therapy starts within three days post-surgery with contralesional inhibitory stimulation (1 Hz; 110% of the individual RMT; 10 min) followed by ipsilesional excitatory stimulation (10 Hz; 110% of the individual RMT; 8 min). Patients perform specific tasks during stimulation to intrinsically activate the language areas. This is followed by 30-45 min of speech and language therapy. In addition to monitoring treatment-related side effects, the primary outcome is assessed using the Aachener Aphasie Test (AAT) before, immediately after, at 1 and 3 months post-therapy. Secondary outcomes are evaluated with the NIHSS and QoL questionnaires.Ten patients were included and all of them completed the rTMS treatment without serious side effects. Seven (70%) patients experienced a mild, temporary headache during a session (VAS≤2), whereby pain medication was only rarely (2/7 sessions in 2 patients) taken additionally. During stimulation over the wound, pain of max. 6 (VAS) was reported in some sessions. No wound healing disorders occured. Short-term outcome analysis (immediately after rTMS therapy) revealed clear improvements of the patients compared to the post-operative deficits (mean AATpre therapy: 196/440; mean AATpost therapy: 258/440). At this time, the follow-up examinations of five patients were completed and showed further improvement (mean AAT3-months: 383/440).The preliminary data indicate that rTMS can be used safely as neuromodulatory technique in the immediate postoperative period. Apart from mild, tolerable headaches, no significant treatment-related side effects were observed. Postoperative neuromodulation represents the first interventional approach to rehabilitate postoperative neurological deficits, the effectiveness of which should be evaluated in subsequent prospective studies.

Motor evoked potential monitoring and continuous dynamic mapping: warning criteria during surgery on 473 intra-axial brain tumors

Monitoring Evozierter Motorischer Potentiale und Kontinuierliches dynamisches Mapping: Warnkriterien während der Operation von 473 intraaxialen Gehirntumoren

We investigated the relationship between intraoperative changes of direct cortical stimulation (DCS) motor evoked potentials (MEP) (Figure 1.A), lowest motor threshold (MT) reached during subcortical dynamic mapping (Figure 1.B), and the patient's motor outcome in a consecutive cohort of patients undergoing surgery for motor eloquent brain tumors under general anesthesia.We included data from 473 intra-axial brain tumor surgeries, 432 of which had motor outcome reported directly after surgery, at discharge and the 3-month follow-up visit. The MEP changes and MT groups were correlated with clinical parameters. Ordinal logistic regression was used to model the motor outcome with respect to the severity of the deficits based on MEP changes, MT groups and clinical parameters.The lower the MT, the higher was the chance of significant MEP changes (Figure 2). MEP changes, MT group and histopathology were predictors of deficit. The more significant the MEP changes and the lower the MT, the higher the likelihood of more severe deficits (Figure 2). MEP loss was associated with 184 times higher odds of causing a deficit than no MEP changes. The lowest dynamic mapping MT group (1–3 mA) was associated with 20% of significant MEP changes and 20% permanent deficits.This study validates intraoperative neurophysiological monitoring paradigms and warning criteria during surgery of motor eloquent brain tumors under general anesthesia. MEP loss and irreversible alteration, as well as low dynamic MT (1–3 mA) should be used as critical intraoperative neurophysiological warning criteria.

Correlation of Interhemispheric Connectivity and Epigenetic Neural Signature in High-Grade Glioma

Korrelation der Interhemisphärischen Konnektivität mit der Epigenetischen Neuralen Signatur in hochgradigen Gliomen

The epigenetic neural signature is linked to survival outcomes in glioblastoma, with a high-neural signature associated with poorer prognosis. Given the resource-intensive nature of epigenetic analyses, we evaluated preoperative tractography as a potential indicator of the neural signature in high-grade glioma.We retrospectively analyzed 19 patients who underwent high-grade glioma resection and received preoperative DTI sequences alongside postoperative 935k analyses. Patients were categorized based on the median neural signature. Tractography of interhemispheric connectivity between each arcuate fascicle (AF), corticospinal tract (CST), frontal aslant tract (FAT), inferior fronto-occipital fascicle (IFOF), inferior longitudinal fascicle (ILF), uncinate fascicle (UF), and optic radiation (OR), was performed using BrainLab. Volume segmentations were evaluated for radiomic diffusion and shape parameters, comparing high-neural and low-neural groups using paired t-tests. P-values were adjusted for multiple comparisons using the Benjamini-Hochberg method.The mean age was 56 (34–72) years, with 53% female patients. One patient suffered from grade 3, 18 from grade 4 glioma. The mean neural signature was 0.43 ± 0.03, with a median of 0.40. After correction for multiple comparisons, significant different patterns in interhemispheric connectivity were observed in FA energy (pcorr= 0.006), FA median (pcorr=0.010), flatness (pcorr =0.036), sphericity (pcorr =0.010), surface area (pcorr =0.006) and voxel volume (pcorr =0.006) of the interhemispheric segmentations.Interhemispheric connectivity varies in high-grade glioma based on the epigenetic neural signature, with high-neural cases exhibiting higher FA values, but smaller tract volumes. In the future, preoperative tractography radiomics may help identify candidates for postoperative epigenetic sequencing.

Session 13
Technik und Innovation 2

Termin

Vorsitz | Chair

Thema

Programm

Session 13Technik und Innovation 2

Termin

Vorsitz | Chair

Thema

Programm

Session 13
Technik und Innovation 2