Low-grade gliomas, which are more frequent in young people, have a better prognosis with total excision, so it is important to judge the degree of excision objectively. For low-grade gliomas, there is a clear correlation between the degree of resection and prognosis, with the greater the degree of resection, the better the prognosis, and a greater difference in prognosis between total and non-total resection, especially for astrocytomas, which account for 75% of low-grade gliomas and are more dependent on surgery to prolong survival. To objectively evaluate the extent of resection, the guidelines recommend MRI T2 or Flair sequences up to 48 h postoperatively as an objective criterion for the extent of resection of low-grade gliomas. Beyond this time window, disruption of the blood-brain barrier due to surgical manipulation or thermal injury due to electrocoagulation will interfere with the objective assessment. In practice, the extent of resection is mostly a subjective judgment of the operator’s experience; or a postoperative CT slice to assess the extent of postoperative resection. There is no timely MRI assessment, and the extent of resection becomes a muddle. Since the objective extent of resection serves as an important reference factor for the selection of subsequent treatment methods, as a basis for the outline of subsequent radiotherapy target areas, as a baseline for the evaluation of subsequent treatment effects, and so on. Therefore, the absence of objective assessment of the extent of resection brings psychological burden and confusion to patients and radiologists, and makes the evaluation of follow-up treatment effects difficult. Therefore, objective criteria for resection of low-grade gliomas are available and important.