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Published on: July 5, 2021
Posterior fossa ependymomas: new radiological classification with surgical correlation
Jean Marie U-King-Im1, Michael D Taylor, Charles Raybaud
1Department of Diagnostic Imaging, Hospital for Sick Children and the University of Toronto, 555 University Ave, Toronto, ON, Canada.
Summary
A new radiological classification system for infratentorial ependymomas helps predict surgical outcomes. Lateral-type tumors have a higher risk of residual tumor compared to midfloor-type tumors, guiding surveillance intensity.
Area of Science:
- Neuro-oncology
- Pediatric Neurosurgery
- Radiology
Background:
- The extent of surgical resection is crucial for the long-term outcome of infratentorial ependymomas.
- Accurate pre-operative assessment aids in surgical planning and predicting outcomes.
Purpose of the Study:
- To introduce and validate a novel radiological classification system for infratentorial ependymomas.
- To correlate this classification with surgical findings and the risk of post-operative residual tumor.
Main Methods:
- A cohort of 25 pediatric patients with infratentorial ependymomas underwent pre-operative MRI classification.
- Tumors were categorized as lateral-type or midfloor-type based on extension patterns and brainstem involvement.
- Classification was validated against operative records, and the risk of residual tumor was assessed.
Main Results:
- The classification identified 15 midfloor-type and 10 lateral-type tumors.
- Radiological classification showed good agreement with operative findings (18/20 cases).
- Lateral-type tumors had a significantly higher risk of residual tumor (80% vs. 33%, p=0.04) compared to midfloor-type tumors.
Conclusions:
- Infratentorial ependymomas can be reliably classified pre-operatively into lateral-type and midfloor-type.
- This classification correlates with operative findings and predicts the risk of residual tumor.
- The classification may inform the intensity of post-operative imaging surveillance.
