3D Pseudocontinuous Arterial Spin-Labeling MR Imaging in the Preoperative Evaluation of Gliomas

Abstract

Background and purpose: Previous studies showed conflicting results concerning the value of CBF maps obtained from arterial spin-labeling MR imaging in grading gliomas. This study was performed to investigate the effectiveness of CBF maps derived from 3D pseudocontinuous arterial spin-labeling in preoperatively assessing the grade, cellular proliferation, and prognosis of gliomas.

Materials and methods: Fifty-eight patients with pathologically confirmed gliomas underwent preoperative 3D pseudocontinuous arterial spin-labeling. The receiver operating characteristic curves for parameters to distinguish high-grade gliomas from low-grade gliomas were generated. Pearson correlation analysis was used to assess the correlation among parameters. Survival analysis was conducted with Cox regression.

Results: Both maximum CBF and maximum relative CBF were significantly higher in high-grade gliomas than in low-grade gliomas (P < .001). The areas under the curve for maximum CBF and maximum relative CBF in distinguishing high-grade gliomas from low-grade gliomas were 0.828 and 0.863, respectively. Both maximum CBF and maximum relative CBF had no correlation with the Ki-67 index in all subjects and had a moderate negative correlation with the Ki-67 index in glioblastomas (r = -0.475, -0.534, respectively). After adjustment for age, a higher maximum CBF (P = .008) and higher maximum relative CBF (P = .005) were associated with worse progression-free survival in gliomas, while a higher maximum relative CBF (P = .033) was associated with better overall survival in glioblastomas.

Conclusions: 3D pseudocontinuous arterial spin-labeling-derived CBF maps are effective in preoperative evaluation of gliomas. Although gliomas with a higher blood flow are more malignant, glioblastomas with a lower blood flow are likely to be more aggressive.

Fig 1.

Enhanced T2-FLAIR images (A, C, and E) and CBF maps (B, D, and F) of a 69-year-old man with oligoastrocytoma (WHO grade II; Ki-67 index, 10%), a 42-year-old man with glioblastoma (WHO grade IV; Ki-67 index, 20%), and a 43-year-old man with glioblastoma (WHO grade IV; Ki-67 index, 60%), respectively. Note that blood flow is significantly elevated in the glioblastoma with a relatively low Ki-67 index, while it is not elevated in the glioblastoma with a very high Ki-67 index. The unit for CBF maps is milliliters/100 g/min.

Fig 2.

Boxplots of CBF_max (A) and rCBF_max (B) in low-grade gliomas and high-grade gliomas for all subjects. The boxplots of CBF_max (C) and rCBF_max (D) in LGGs and HGGs after the oligodendrogliomas and anaplastic oligodendrogliomas were excluded. ### indicates P < .001, compared with LGG.

Fig 3.

Receiver operating characteristic curves of CBF_max (A) and rCBF_max (B) in distinguishing high- from low-grade gliomas, without (black line) or with (red line) oligodendrogliomas and anaplastic oligodendrogliomas excluded.

Fig 4.

The linear regression of CBF_max (A–C) and rCBF_max (D–F) with the Ki-67 index in all subjects (A and D), in the low and high Ki-67 groups (B and E), and in glioblastomas (C and F). The low Ki-67 group included patients with a Ki-67 index of <30%, and the high Ki-67 group included patients with a Ki-67 index of ≥30%.