Low-grade gliomas account for about half of all gliomas and are generally slow-growing with a good prognosis, which is better if total or expanded resection is possible. We generally define the extent of the tumor by the abnormal signal on the T2 or Flair sequence, and the goal of surgery is to remove as much of the abnormal signal as possible while preserving function. The goal of surgery is to remove as many abnormal signals as possible while preserving function. The patient’s opportunity for surgery is very precious, especially when it is the first surgery, so it is important to achieve the maximum safe resection at the time of surgery, thus maximizing the patient’s benefit. The extent of resection is evaluated with a T2 sequence or Flair sequence up to 48 h postoperatively. Unless the patient is not in a condition to have an MRI, such as coma or uncooperative. If the patient’s condition allows, the patient must be given a T2 sequence or Flair sequence up to 48 h postoperatively to assess the extent of resection. This level of resection is the baseline for subsequent treatment. Without a T2 sequence or Flair sequence within 48 h of surgery to assess the extent of resection, it is not standard and the extent of resection may always be a muddle. The assessment of the extent of resection for low-grade gliomas is only standardized if one dares to show a T2 or Flair sequence within 48 h postoperatively. Saying how much or how little was excised based only on a postoperative CT …….. Not reliable.