Brainlab (Germany)

Tractography is a time consuming and operator-dependent process. Neuronavigation softwares can perform automatic segmentation of MRI data to recognize several anatomical structures to be included in surgical planning. Aim of the present investigation is to define if a semi-automatic (SA) method for tractography based on auto-segmented anatomical structures is non-inferior to standard ROI-based method (RB) for long associative white matter tracts in patients with brain tumor. Tractography of bilateral inferior fronto-occipital fascicle, inferior longitudinal fascicle, and superior longitudinal fascicle was performed in patients affected from brain tumor both with SA and with a standard RB technique with a commercially available neuronavigation software. The tracts produced were then compared in terms of quality and efficiency. In particular, two independent raters assigned a mark for the quality of each tract. Moreover, the time needed to perform the elaboration of each tract was evaluated. Forty patients were included in the study for a total of 240 tracts. The SA method was able to produce the planned tracts in all but one tract (99.6%). In comparison with RB tracts, the quality of the SA tracts was considered inadequate in two cases (0.8%), sufficient for neurosurgical planning in 15 tracts (6.4%) while slightly inferior or equivalent to RB in 37 (15.4%) and 185 (77.1%) tracts respectively. The time needed to elaborate the tracts was significantly inferior in the SA group (p < 0.001). A semi-automatic method was accurate and efficient in performing tractography of long associative white matter tracts in the context of neurosurgical planning for brain tumor patients. Clinical applications should be tested in future studies.

IDH-mutant astrocytomas (AIDHmut) in the posterior cranial fossa (PCF) are rare and present substantial diagnostic and therapeutic challenges due to their location. We analyzed patients with PCF AIDHmut from our institutions, treated between December 2021 and September 2024. Additionally, we conducted a systematic literature review (from January 2021 to September 2024) using PubMed, Ovid MEDLINE, and Ovid EMBASE to identify cases of PCF AIDHmut. We identified a total of 19 cases, including one institutional case. Most patients were young adults, with a male predominance (15 males, 4 females). Tumors primarily originated from the brainstem (94.7%), with only one case involving the cerebellum. Clinical presentations frequently included cranial nerve deficits, with diplopia being the most common symptom (47.4%). Adjuvant radiotherapy (IMRT, DT 54 Gy/27 fractions, 78.9%) and chemotherapy (temozolomide, 68.4%) formed the mainstays of treatment. Tumor grading revealed 63.2% (12/19) were WHO grade 2, 21% (4/19) were WHO grade 3, and 15.8% (3/19) were grade 4. The mean follow-up period was 45 months. PCF AIDHmut are rare but pose significant treatment challenges due to their location and infiltrative nature. Multimodal treatment—comprising surgery, radiotherapy, and chemotherapy—is essential for achieving long-term disease control. Subtotal resection followed by adjuvant therapies provides a favorable balance between tumor control and functional preservation.

Radiotherapy developed empirically through experience balancing tumour control and normal tissue toxicities. Early simple mathematical models formalized this practical knowledge and enabled effective cancer treatment to date. Remarkable advances in technology, computing, and experimental biology now create opportunities to incorporate this knowledge into enhanced computational models.The ESTRO DREAM (Dose Response, Experiment, Analysis, Modelling) workshop brought together experts across disciplines to pursue the vision of personalized radiotherapy for optimal outcomes through advanced modelling. The ultimate vision is leveraging quantitative models dynamically during therapy to ultimately achieve truly adaptive and biologically guided radiotherapy at the population as well as individual patient-based levels. This requires the generation of models that inform response-based adaptations, individually optimized delivery and enable biological monitoring to provide decision support to clinicians. The goal is expanding to models that can drive the realization of personalized therapy for optimal outcomes.This position paper provides their propositions that describe how innovations in biology, physics, mathematics, and data science including AI could inform models and improve predictions. It consolidates the DREAM team’s consensus on scientific priorities and organizational requirements. Scientifically, it stresses the need for rigorous, multifaceted model development, comprehensive validation and clinical applicability and significance. Organizationally, it reinforces the prerequisites of interdisciplinary research and collaboration between physicians, medical physicists, radiobiologists, and computational scientists throughout model development. Solely by a shared understanding of clinical needs, biological mechanisms, and computational methods, more informed models can be created. Future research environment and support must facilitate this integrative method of operation across multiple disciplines.

Background and PurposeSafe reirradiation relies on assessment of cumulative doses to organs at risk (OARs) across multiple treatments. Different clinical pathways can result in inconsistent estimates. Here, we quantified the consistency of cumulative dose to OARs across multi-centre clinical pathways. Material and MethodsWe provided DICOM planning CT, structures and doses for two reirradiation cases: head & neck (HN) and lung. Participants followed their standard pathway to assess the cumulative physical and EQD2 doses (with provided α/β values), and submitted DVH metrics and a description of their pathways. Participants could also submit physical dose distributions from Course 1 mapped onto the CT of Course 2 using their best available tools. To assess isolated impact of image registrations, a single observer accumulated each submitted spatially mapped physical dose for every participating centre. ResultsCumulative dose assessment was performed by 24 participants. Pathways included rigid (n = 15), or deformable (n = 5) image registration-based 3D dose summation, visual inspection of isodose line contours (n = 1), or summation of dose metrics extracted from each course (n = 3). Largest variations were observed in near-maximum cumulative doses (25.4 – 41.8 Gy for HN, 2.4 – 33.8 Gy for lung OARs), with lower variations in volume/dose metrics to large organs. A standardised process involving spatial mapping of the first course dose to the second course CT followed by summation improved consistency for most near-maximum dose metrics in both cases. ConclusionLarge variations highlight the uncertainty in reporting cumulative doses in reirradiation scenarios, with implications for outcome analysis and understanding of published doses. Using a standardised workflow potentially including spatially mapped doses improves consistency in determination of accumulated dose in reirradiation scenarios.

Objective: The present study aims at characterizing the functional status of the central nervous system (CNS) in encoding speech sounds in large-for-gestational-age (LGA) neonates as examined through a sensitive auditory evoked potential termed frequency-following response (FFR). Design: Case-control study. Setting: SJD Barcelona Children’s Hospital (Catalonia, Spain). Population: A sample of 25 LGA neonates were paired by age and sex with 25 born adequate-for-gestational-age (AGA). Methods: Descriptive statistics were calculated for sociodemographic characteristics of the mother and their neonates. Categorical demographic and electrophysiological variables were analyzed by Chi-square test and continuous variables with t test or Mann-Whitney U test. Main Outcome Measures: The primary clinical outcomes were the FFR spectral amplitude and its normalization. Both magnitudes reflect the neural encoding strength of the fundamental frequency of the eliciting stimulus. Results: LGA neonates displayed smaller spectral amplitudes compared to the AGA group (consonant transition: P = .002; vowel: P = .004) as well as smaller normalized spectral amplitudes (consonant transition: P = .01; vowel: P = .003). Conclusions: This study reveals for the first time perinatal CNS consequences of being born LGA, characterized by a deficient neural encoding of speech sounds. Funding: This work was supported by the Spanish Ministry of Science and Universities PGC2018-094765-B-I00 project and the MDM-2017-0729-18-2 Maria de Maeztu Center of Excellence, the 2017SGR-974 Excellence Research Group of the Generalitat de Catalunya, and the ICREA Acadèmia Distinguished Professorship awarded to Carles Escera. Keywords: auditory brainstem response, auditory evoked potentials, BMI, EEG, FFR, macrosomia, newborn, neonatal adiposity, universal hearing screening.

Our actions shape our everyday experience: what we experience, how we perceive and remember it, is deeply affected by how we interact with the world. Performing an action to deliver a stimulus engages neurophysiological processes which are reflected in the modulation of sensory and pupil responses. In this study, we hypothesized that these processes shape memory encoding, parsing the experience by grouping self- and externally-generated stimuli into differentiated events. Participants encoded sound sequences, in which either the first or last few sounds were self-generated and the rest externally-generated. We tested recall of the sequential order of sounds that had originated from the same (within event) or different sources (across events). Memory performance was not higher for within event sounds, suggesting that the memory representation was not structured by actions. However, during encoding, we replicated the well-known electrophysiological response attenuation, together with increased pupil dilation for self-generated sounds. Moreover, we found that at the boundary between events, physiological responses to the first sound originating from the new source were determined by the direction of the source switch. The results suggest that introducing actions, acts as a stronger contextual shift than removing them, despite not directly contributing to memory performance. The findings contribute to our understanding of how interacting with sensory input shapes our experiences, by addressing the unexplored relationships between action effects on sensory responses, pupil dilation and memory encoding, and discarding a meaningful contribution of low-level neurophysiological mechanisms associated to action execution in the modulation of memory.

Background: To investigate the accuracy of augmented reality (AR) navigation using the Magic Leap head mounted device (HMD), pedicle screws were minimally invasively placed in four spine phantoms. Methods: AR navigation provided by a combination of a conventional navigation system integrated with the Magic Leap head mounted device (AR-HMD) was used. Forty-eight screws were planned and inserted into Th11-L4 of the phantoms using the AR-HMD and navigated instruments. Postprocedural CT scans were used to grade the technical (deviation from the plan) and clinical (Gertzbein grade) accuracy of the screws. The time for each screw placement was recorded. Results: The mean deviation between navigation plan and screw position was 1.9 ± 0.7 mm (1.9 [0.3–4.1] mm) at the entry point and 1.4 ± 0.8 mm (1.2 [0.1–3.9] mm) at the screw tip. The angular deviation was 3.0 ± 1.4° (2.7 [0.4–6.2]°) and the mean time for screw placement was 130 ± 55 s (108 [58–437] s). The clinical accuracy was 94% according to the Gertzbein grading scale. Conclusion: The combination of an AR-HMD with a conventional navigation system for accurate minimally invasive screw placement is feasible and can exploit the benefits of AR in the perspective of the surgeon with the reliability of a conventional navigation system.

For complex spinal cases, especially when robotic guidance is used, preoperative planning of pedicle screws can be helpful. Transfer of these preoperatively planned pedicle screws to intraoperative 3-dimensional imaging is challenging because of changes in anatomic alignment between preoperative supine and intraoperative prone imaging, especially when multiple levels are involved. In the spine, where each individual vertebra is subject to independent movement from adjacent level, rigid image fusion is confined to a single vertebra and can display fusion inaccuracies on adjacent levels. A novel elastic fusion algorithm is introduced to overcome these disadvantages. This study aimed to investigate image registration accuracy of preoperatively planned pedicle screws with an elastic fusion algorithm vs. rigid fusion for intraoperative placement with image-guided surgery. A total of 12 patients, were selected depending on the availability of a preoperative spinal computed tomography (CT) and an intraoperative AIRO CT scan (BrainLAB AG, Munich, Germany) of the same spinal region. To verify accuracy differences between rigid fusion and elastic fusion 76 bilateral screw trajectories were virtually defined in the preoperative CT image, and they were transferred via either rigid fusion or elastic fusion to the intraoperative CT scan. Accuracy of the transferred screws in the rigid and elastic fusion group was determined by measuring pedicle breaches on the intraoperative CT. In the rigid fusion group 1.3% of screws showed a breach of less than 2 mm, 9.2% showed breaches between 2 and 4 mm, and 18.4% of the screws showed an error above 4 mm. The elastic fusion group showed no breaches and provided high accuracy between preoperative and intraoperative screw placement. Elastic fusion provides high registration accuracy and represents a considerable step towards efficiency and safety in CT-based image-guided surgery. 3.