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Intraoperative 3 T MRI is more correlative to residual disease extent than early postoperative MRI
Kristin Huntoon1,2, Mina S Makary3, Mark Damante4
1Department of Neurological Surgery, Ohio State University Wexner Medical Center, Columbus, OH, USA. Khuntoon@mdanderson.org.
Purpose:
Extent of resection of low grade glioma (LGG) is an important prognostic variable, and may influence decisions regarding adjuvant therapy in certain patient populations. Immediate postoperative magnetic resonance image (MRI) is the mainstay for assessing residual tumor. However, previous studies have suggested that early postoperative MRI fluid-attenuated inversion recovery (FLAIR) (within 48 h) may overestimate residual tumor volume in LGG. Intraoperative magnetic resonance imaging (iMRI) without subsequent resection may more accurately assess residual tumor. Consistency in MRI techniques and utilization of higher magnet strengths may further improve both comparisons between MRI studies performed at different time points as well as the specificity of MRI findings to identify residual tumor. To evaluate the utility of 3 T iMRI in the imaging of LGG, we volumetrically analyzed intraoperative, early, and late (~ 3 months after surgery) postoperative MRIs after resection of LGG.
Methods:
A total of 32 patients with LGG were assessed retrospectively. Residual tumor was defined as hyperintense T2 signal on FLAIR. Volumetric assessment was performed with intraoperative, early, and late postoperative FLAIR via TeraRecon iNtuition.
Results:
Perilesional FLAIR parenchymal abnormality volumes were significantly different comparing intraoperative and early postoperative MRI (2.17 ± 0.45 cm3 vs. 5.47 ± 1.07 cm3, respectively (p = 0.0002)). A significant difference of perilesional FLAIR parenchymal abnormality volumes was also found comparing early and late postoperative MRI (5.47 ± 1.07 cm3 vs. 3.22 ± 0.64 cm3, respectively (p = 0.0001)). There was no significant difference between intraoperative and late postoperative Perilesional FLAIR parenchymal abnormality volumes.
Conclusions:
Intraoperative 3 T MRI without further resection appears to better reflect the volume of residual tumor in LGG compared with early postoperative 3 T MRI. Early postoperative MRI may overestimate residual tumor. As such, intraoperative MRI performed after completion of tumor resection may be more useful for making decisions regarding adjuvant therapy.
Insights
Intraoperative 3 Tesla MRI (iMRI) more accurately assesses residual low-grade glioma (LGG) tumor volume than early postoperative MRI. This finding aids in treatment decisions by providing a more precise measure of residual tumor post-resection.
Area of Science:
- Neurosurgery
- Neuroradiology
- Oncology
Background:
- Extent of resection is crucial for low-grade glioma (LGG) prognosis and adjuvant therapy decisions.
- Immediate postoperative MRI is standard for assessing residual tumor, but early scans may overestimate LGG volume.
- Intraoperative MRI (iMRI) may offer a more accurate assessment of residual tumor without further resection.
Purpose of the Study:
- To evaluate the utility of 3 Tesla intraoperative MRI (iMRI) in assessing residual low-grade glioma (LGG) tumor volume.
- To compare volumetric assessments from iMRI, early postoperative MRI, and late postoperative MRI.
- To determine if iMRI provides a more accurate representation of residual LGG compared to early postoperative imaging.
Main Methods:
- Retrospective analysis of 32 patients with LGG.
- Volumetric assessment of residual tumor using fluid-attenuated inversion recovery (FLAIR) sequences on 3 Tesla MRI.
- Comparison of MRI scans obtained intraoperatively, within 48 hours postoperatively, and approximately 3 months postoperatively.
Main Results:
- Perilesional FLAIR parenchymal abnormality volumes differed significantly between intraoperative (2.17 ± 0.45 cm³ ) and early postoperative (5.47 ± 1.07 cm³ ) MRI (p=0.0002).
- Significant differences were also observed between early (5.47 ± 1.07 cm³ ) and late (3.22 ± 0.64 cm³ ) postoperative MRI volumes (p=0.0001).
- No significant difference was found in perilesional FLAIR parenchymal abnormality volumes between intraoperative and late postoperative MRI.
Conclusions:
- Intraoperative 3 Tesla MRI (iMRI) appears to more accurately reflect residual LGG tumor volume than early postoperative MRI.
- Early postoperative MRI may overestimate residual tumor volume in LGG.
- iMRI performed after tumor resection completion may be more valuable for guiding adjuvant therapy decisions.
