NTMS-derived DTI-based motor fiber tracking in radiotherapy treatment planning of high-grade gliomas for avoidance of motor structures. (June 2022)

• Record Type: Journal Article
• Authors: Diehl, Christian D.; Rosenkranz, Enrike; Mißlbeck, Martin; Schwendner, Maximilian; Sollmann, Nico; Ille, Sebastian; Meyer, Bernhard; Combs, Stephanie E.; Bernhardt, Denise; Krieg, Sandro M.
• Is Part Of: Radiotherapy and oncology. Volume 171(2022)
• Page Start: 189
• Page End: 197
• Publication Date: 2022-06
• Subjects: ATRX alpha thalassemia/mental retardation syndrome X-linked -- BMRC British Medical Research Council -- CST corticospinal tract -- DES direct electrical stimulation -- DTI-FT diffusion tensor imaging fiber tracking -- FLAIR fluid attenuated inversion recovery -- ICRU International Commission On Radiation Units And Measurements -- IMRT intensity-modulated radiation therapy -- MEP motor-evoked potential -- MGMT methyl-guanin-methyl-transferase -- nTMS navigated transcranial magnetic stimulation -- OAR organ at risk -- PRV planning risk volume -- QUANTEC Quantitative Analysis of Normal Tissue Effects in the Clinic -- rMT resting motor threshold -- TPS treatment planning system -- WHO World Health Organization -- WM white matter -- BOLD-fMRI blood oxygenation level dependent functional magnetic resonance imaging -- MRI magnetic resonance imaging -- ROI region of interest -- EF elastic fusion -- DVH dose volume histogram -- VMAT volumetric-modulated arc therapy -- HGG high-grade glioma; Brain mapping -- Eloquent tumor -- High-grade glioma -- Motor mapping -- Navigated transcranial magnetic stimulation -- Subcortical fiber tracts; Oncology -- Periodicals; Radiotherapy -- Periodicals; Tumors -- Periodicals; Medical Oncology -- Periodicals; Neoplasms -- radiotherapy -- Periodicals; Radiotherapy -- Periodicals; Radiothérapie -- Périodiques; Cancérologie -- Périodiques; Tumeurs -- Périodiques; Electronic journals; 616.9940642
• DOI: 10.1016/j.radonc.2022.04.012
• Languages: English
• ISSNs: 0167-8140

Abstract

Highlights: nTMS (DTI-FTTMS detects cortical and subcortical motor areas. nTMS (DTI-FTTMS ) detects cortical and subcortical motor areas. DTI-FTTMS can be easily implemented in RT planning of motor-eloquent glioma. With DTI-FTTMS the corticospinal tract can be spared without affecting PTV dose. Our approach might help to avoid neurological sequelae after RT. Abstract: Background: Management of high-grade gliomas (HGGs) close to motor areas is challenging due to the risk of treatment-related morbidity. Thus, for resection, functional mapping of the corticospinal tract (CST) with navigated transcranial magnetic stimulation (nTMS) combined with diffusion tensor imaging (DTI)-based fiber tracking (DTI-FTTMS ) is increasingly used. This study investigated the application of DTI-FTTMS in adjuvant radiation therapy (RT) planning of HGGs for CST avoidance. Methods: The preoperative DTI-FTTMS -based CST reconstructions of 35 patients harboring HGGs were incorporated into the RT planning system and merged with planning imaging. The CST was delineated as the planning risk volume (PRV-FTTMS ). Intensity-modulated RT (IMRT) plans were optimized to preserve PRV-FTTMS . Segments within the planning target volume (PTV) were not spared (overlap). Results: With plan optimization, mean dose (Dmean) of PRV-FTTMS can be reduced by 17.1% on average (range 0.1–37.9%), thus from 25.5 Gy to 21.2 Gy ( p < 0.001). For PRV-FTTMS segments beyond the PTV dose, reduction is possible by 26.8% (range 0.1–43.9%, Dmean 17.4 Gy vs. 12.5 Gy, p < 0.001). Considering only portions within the 50% isodose level, Dmean is decreased by 46.7% from 38.6 Gy to 20.5 Gy (range 19.1–62.8%, p < 0.001). PTV coverage was not affected: V95% and V90% were 96.4 ± 3.1% and 98.0 ± 3.9% vs. 96.1 ± 3.5% ( p = 0.34) and 98.3 ± 2.9% ( p = 0.58). Dose constraints for organs at risk (OARs) were all met. Conclusion: This study demonstrates that DTI-FTTMS can be utilized in the RT planning of HGGs for CST sparing. However, the degree of dose reduction depends on the overlap with the PTV. The functional benefit needs to be investigated in future prospective clinical trials.