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Updated: May 10, 2026
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Published on: February 27, 2026
Postoperative ischemic changes after glioma resection identified by diffusion-weighted magnetic resonance imaging and
Jens Gempt1, Sandro M Krieg, Stefanie Hüttinger
1Neurochirurgische Klinik und Poliklinik; and.
Object:
The aim of surgical glioma treatment is the complete resection of tumor tissue while preserving neurological function. Surgery-related neurological deficits arise from direct damage to the cortical or subcortical structures or from ischemia. The authors aimed to assess the incidence of resection-related ischemia of newly diagnosed or recurrent supratentorial gliomas and the sensitivity of intraoperative neuromonitoring (IOM) of motor evoked potentials (MEPs) for detecting such ischemic events and their influence on neurological motor function.
Methods:
Between January 2009 and December 2010, 70 patients with tumors in motor-eloquent brain areas underwent intraoperative MEP monitoring during glioma resection and were examined by early postoperative MRI including diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) mapping. Postoperative areas of restricted diffusion were assessed by investigators blinded to the course of intraoperative MEPs and the neurological course.
Results:
Among the 70 enrolled patients, a MEP amplitude decline below 50% of the baseline level was observed in 21 patients (30%). Sixteen of these patients (76%) had ischemic lesions identified on postoperative MRI scans. Forty-nine patients (70%) showed no decline in MEP amplitude, and only 16 (33%) of these patients harbored ischemic lesions. Moreover, 9 (69%) of 13 patients with a permanent loss of MEP amplitude showed postoperative ischemic lesions. Factors that promoted the occurrence of postoperative infarction were previous radiotherapy and location of the tumor close to the central arteries.
Conclusions:
Alterations in the MEP amplitude during tumor resection and postoperative ischemic lesions are associated with postoperative impairment of motor function. Rather than cortical or subcortical structural damage of eloquent brain tissue alone, peri- or postoperative ischemic lesions play a crucial role in the development of surgery-related motor deficits.
Insights
Intraoperative monitoring of motor evoked potentials (MEPs) can detect resection-related ischemia during glioma surgery. Postoperative ischemic lesions, not just structural damage, significantly impact motor function after surgery.
Area of Science:
- Neurosurgery
- Neurology
- Neuroradiology
Background:
- Complete surgical resection of gliomas is crucial for patient outcomes.
- Neurological deficits post-glioma surgery can result from direct tissue damage or ischemia.
- Intraoperative neuromonitoring (IOM) is vital for preserving function during surgery.
Purpose of the Study:
- To determine the incidence of resection-related ischemia in supratentorial gliomas.
- To evaluate the sensitivity of motor evoked potentials (MEPs) in detecting ischemic events.
- To assess the impact of ischemia on postoperative neurological motor function.
Main Methods:
- 70 patients with gliomas in motor-eloquent areas were monitored using MEPs.
- Postoperative MRI, including DWI and ADC mapping, was used to identify ischemic lesions.
- Investigators assessed diffusion-weighted imaging (DWI) findings blinded to MEP and clinical data.
Main Results:
- A decline in MEP amplitude (<50% baseline) occurred in 30% of patients, with 76% showing ischemic lesions.
- No MEP decline was observed in 70% of patients, but 33% still had ischemic lesions.
- Previous radiotherapy and tumor proximity to central arteries increased the risk of postoperative infarction.
Conclusions:
- MEP amplitude changes during glioma resection correlate with postoperative ischemic lesions.
- Ischemic events, alongside structural damage, play a critical role in motor deficits after surgery.
- IOM of MEPs is valuable for identifying and potentially mitigating surgery-related ischemia and motor impairment.
