Abstract: Background and purpose: It is difficult to eradicate high-grade gliomas (HGG) due to their invasive growth. Postoperative  adiochemotherapy can improve the prognosis of the patients. Three-dimensional arterial spin labeling (3D-ASL) technique has been  uccessfully used as a significant non-invasive method for preoperative diagnosis in HGG. This study explored its usefulness to assess residual tumor burden after resection of glioma before postoperative radiotherapy. Methods: From March 2015 to May 2017, 30 patients with pathologically confirmed HGG (12 of grade Ⅲ and 18 of grade Ⅳ) in Guizhou Provincial People’s Hospital were examined after tumor resection by conventional MRI and 3D-ASL scan. The data of 3D-ASL scan signals at the regions of interest in these patients were analyzed to investigate the evolution of the tumor blood flow (TBF), normalized TBF (nTBF) and contralateral white matter blood flow (CBFwm). Results: The 3D-ASL data of the 30 patients were divided into two groups according to clinical diagnosis. The results showed that the residual tumor positive group (20 patients) displayed high ASL perfusion whereas the residual cavity group (10 patients) displayed low ASL perfusion. The TBF was (85.97±17.54) mL/min in the residual tumor positive group, and (26.51±8.93) mL/min in the residual cavity group. The nTBF was 4.19±1.58 in the residual tumor positive group, and 0.91±0.44 in the residual cavity group. The differences between the two groups were statistically significant (P<0.01). However CBFwm showed no statistically significant difference (P>0.05). Conclusion: The significantly higher perfusion index of TBF and nTBF in residual tumor group of HGG patients indicates existence of residual tumors and rich microvascular angiogenesis in these patients. Therefore, 3D ASL technique is recommended in HGG patients after tumor resection, so as to facilitate clinical decision making for postoperative chemotherapy and radiotherapy.

Key words: High-grade gliomas, Three-dimensional arterial spin labeling, Radiotherapy, Tumor blood flow