Planning and optimizing surgery for brain tumors
Using navigated transcranial magnetic stimulation combined with DTI-based fiber tractography enables surgeons to make improvements in the surgical planning process and the overall outcome of brain tumor surgery. Due to exact operational planning, patients benefit from a higher extent of resection and a lower risk of severe, postoperative neurological deficits. Dr. med. Tizian Rosenstock, Junior Digital Clinician Scientist of the Berlin Institute of Health (BIH), and his team are researching the technologies mentioned above in order to increase the quality of treatments offered to brain tumor patients.
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Cooperation
Dr. med. Tizian Rosenstock is a scholar of the Junior Digital Clinician Scientist Program of the Berlin Institute of Health (BIH). The BIH supports his research group of the Image Guidance Lab by providing them with their expertise.
When it comes to planning and executing complex statistical analyses, Dr. med. Tizian Rosenstock and his team are working in cooperation with the Institute for Biometry of PD Dr. Ulrike Grittner, in order to competently give medical advice to patients with regard to their individual operation risk.
Prof. Dr. Christoph Lippert is the head of the academic chair of “Digital Health & Machine Learning” of the Hasso Plattner Institute. Being an expert in this field, he is our ideal partner for the development of Machine Learning-aided data analysis and the corresponding software tools.
Furthermore, we work together with research groups from diverse international universities for the purpose of finding answers to specific research questions: MD Anderson Cancer Center – University of Texas (Prof. Dr. Sujit Prabhu), King’s College Hospital London (Prof. Dr. Francesco Vergani), University Hospital of Bern “Inselspital” (Dr. med. Kathleen Seidel), University of Messina – Department of Neurosurgery (Dr. Giovanni Raffa), Technical University of Munich (Prof. Dr. med. Sandro Krieg), University Hospital of Cologne (Dr. med. Carolin Weiß Lucas), Vivantes Hospital in Neukölln (PD Dr. med. Andreas Jödicke), Helios Hospital in Berlin-Buch (PD Dr. med. Yu-Mi Ryang).
TMS motor mapping and preoperative risk stratification
With the aid of motor mapping and the DTI-based visual representation of the pyramidal tract, a patient’s individual risk of a postoperative paresis (= newly occurred motor weakness) can be objectively measured. This procedure has an advantageous impact on patient counselling and the surgical planning process. The exact spatial analysis of brain structures allows surgeons to precisely differentiate between tumor tissue and functional brain regions and is of high relevance for successful and safe tumor resection. With this technique, we are able to offer a perspective to patients who were previously diagnosed with an inoperable brain tumor.
Using novel approaches in analysis technologies (Machine Learning) in a multicenter study, we are aiming to discover new findings for further improving operational planning and the quality of our treatments.
TMS speech mapping
The first study describing the navigated transcranial magnetic stimulation (TMS) as non-inavsive diagnostic tool to analyze speech-associated brain areas was published in 2012 by Lioumis et al. The principle of TMS speech mapping consists in a repetitive stimulation (rTMS) inducing a focal functional lesion by inhibiting neurons. During the stimulation, the patient might be not able to talk properly which indicates that the stimulated brain area is involved in speech processing or production. In a comparative study with intraoperative direct cortical stimulation (DCS) as gold standard for identifying functional eloquence, TMS shows good sensitivity (90%) and a moderate speficity (24%) (Picht et al. 2013). The stimulation parameters have been evaluated by an international consensus-group which has also been published (Krieg et al. 2017). Additionally, some recent publications are showing evidence that TMS data are also useful to improve the MRI-DTI-based tractography of the language network (e.g. Raffa et al. 2016).
TMS mapping in children
Equally to TMS mapping procedures in adults, the identification of functional eloquent areas in children with a brain tumor is very important and can enrich the surgical planning and the counselling. We have published a case report where a 6-year-old boy with a speech-eloquent brain tumor underwent TMS speech mapping with consecutive analysis of the language network for the first time. The operation strategy was adapted based on the data provided by TMS and the TMS-based tractography. With different projects, we aim to optimize the TMS mapping in children.
Treatment of a postoperative paresis after brain tumor surgery with TMS
It is known that a hemiparesis after ischemic stroke is not only caused by damaged neurons in the lesional hemisphere but also by an unbalanced interhemispheric excitability. In detail, the regular callosal inhibition of the healthy hemisphere by the lesional is missing. Consecutively, the healthy hemisphere is more active which results in an “over-inhibition” of the lesional hemisphere (Perez et al. 2009). The principle of the TMS treatment is to compensate this unbalanced interhemispheric excitability by inhibiting the “over-active” healthy hemisphere. In stroke studies, patients treated with TMS had a better and faster recovery.
Sources
1. Rosenstock T, Picht T, Schneider H, Koch A, Thomale UW. Left perisylvian tumor surgery aided by TMS language mapping in a 6-year-old boy: case report. Childs Nerv Syst. 2018. doi: 10.1007/s00381-018-3944-1.
2. Schwarzer V, Bährend I, Rosenstock T, Dreyer FR, Vajkoczy P, Picht T. Aphasia and cognitive impairment decrease the reliability of rnTMS language mapping. Acta Neurochir (Wien). 2018;160(2):343-356.
3. Zdunczyk A, Schwarzer V, Mikhailov M, Bagley B, Rosenstock T, Picht T, Vajkoczy P. The Corticospinal Reserve Capacity: Reorganization of Motor Area and Excitability As a Novel Pathophysiological Concept in Cervical Myelopathy. Neurosurgery. 2018;83(4):810-818.
4. Rosenstock T, Giampiccolo D, Schneider H, Runge SJ, Bährend I, Vajkoczy P, Picht T. Specific DTI seeding and diffusivity-analysis improve the quality and prognostic value of TMS-based deterministic DTI of the pyramidal tract. Neuroimage Clin. 2017;16:276-285.
5. Rosenstock T, Grittner U, Acker G, Schwarzer V, Kulchytska N, Vajkoczy P, Picht T. Risk stratification in motor area-related glioma surgery based on navigated transcranial magnetic stimulation data. J Neurosurg. 2017;126(4):1227-1237.
6. Rosenstock T, Hermann KG. Septic Sacroiliitis Following Corticosteroid Injection in a Patient Under Anti-Tumor Necrosis Factor Therapy. J Clin Rheumatol. 2015;21(6):320-1.