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Updated: Oct 6, 2025
Diffusion Tensor Magnetic Resonance Imaging in Chronic Spinal Cord Compression
Published on: May 7, 2019
TMS Seeded Diffusion Tensor Imaging Tractography Predicts Permanent Neurological Deficits
Matthew Muir1, Sarah Prinsloo1, Hayley Michener1
1Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
Abstract:
Surgeons must optimize the onco-functional balance by maximizing the extent of resection and minimizing postoperative neurological morbidity. Optimal patient selection and surgical planning requires preoperative identification of nonresectable structures. Transcranial magnetic stimulation is a method of noninvasively mapping the cortical representations of the speech and motor systems. Despite recent promising data, its clinical relevance and appropriate role in a comprehensive mapping approach remains unknown. In this study, we aim to provide direct evidence regarding the clinical utility of transcranial magnetic stimulation by interrogating the eloquence of TMS points. Forty-two glioma patients were included in this retrospective study. We collected motor function outcomes 3 months postoperatively. We overlayed the postoperative MRI onto the preoperative MRI to visualize preoperative TMS points in the context of the surgical cavity. We then generated diffusion tensor imaging tractography to identify meaningful subsets of TMS points. We correlated the resection of preoperative imaging features with clinical outcomes. The resection of TMS-positive points was significantly predictive of permanent deficits (p = 0.05). However, four out of eight patients had TMS-positive points resected without a permanent deficit. DTI tractography at a 75% FA threshold identified which TMS points are essential and which are amenable to surgical resection. TMS combined with DTI tractography shows a significant prediction of postoperative neurological deficits with both a high positive predictive value and negative predictive value.
Insights
Transcranial magnetic stimulation (TMS) combined with diffusion tensor imaging (DTI) tractography can predict postoperative neurological deficits in glioma patients. This approach helps surgeons balance maximal tumor resection with minimal neurological damage.
Area of Science:
- Neurosurgery
- Neuroscience
- Medical Imaging
Background:
- Optimizing the onco-functional balance in surgery requires maximizing resection while minimizing neurological deficits.
- Preoperative identification of nonresectable structures is crucial for surgical planning.
- Transcranial magnetic stimulation (TMS) noninvasively maps speech and motor systems, but its clinical utility in neurosurgery is not fully established.
Purpose of the Study:
- To provide direct evidence on the clinical utility of TMS in neurosurgery by assessing the eloquence of TMS points.
- To evaluate the predictive value of TMS, combined with diffusion tensor imaging (DTI) tractography, for postoperative neurological deficits in glioma patients.
Main Methods:
- Retrospective study of 42 glioma patients.
- Preoperative TMS mapping of speech and motor systems.
- Postoperative MRI overlaid with preoperative MRI to visualize TMS points relative to the surgical cavity.
- Diffusion tensor imaging (DTI) tractography to identify essential versus resectable TMS points.
- Correlation of resected TMS points with 3-month postoperative motor function outcomes.
Main Results:
- Resection of TMS-positive points was significantly predictive of permanent deficits (p=0.05).
- Four out of eight patients with resected TMS-positive points experienced no permanent deficit, indicating variability.
- DTI tractography at a 75% FA threshold effectively distinguished essential TMS points from those amenable to resection.
- Combined TMS and DTI tractography demonstrated high positive and negative predictive values for postoperative neurological deficits.
Conclusions:
- TMS, when integrated with DTI tractography, offers significant predictive power for postoperative neurological deficits in glioma surgery.
- This combined approach aids surgeons in optimizing the onco-functional balance by identifying critical eloquent areas.
- Further research is warranted to define the precise role of TMS in comprehensive pre-surgical mapping strategies.
