In an adult with localized spinal myxopapillary ependyoma managed with subtotal resection and 54 Gy radiation, how long should follow up MRI imaging continue, with what frequency, and for what volume?  

This is an excellent question. I don't think we have clear surveillance guidelines for many primary spinal tumors, including WHO gr. 2 ependymomas like myxopapillary ependymoma. In our institution, we generally obtain total spine MRI with dedicated imaging at the tumor level q4 months in the first 2...

Would agree with the approximate surveillance protocol listed by Dr. @Lazarev. European ependymoma guidance (Rudà et al., PMID 29194500) also states because of the risks of long-term/late relapses that MPE patients should be followed up long-term with contrast-enhanced MRI.