Arterial spin-labeling perfusion MRI stratifies progression-free survival and correlates with epidermal growth factor receptor status in glioblastoma

Abstract

Background and purpose: Glioblastoma is a common primary brain tumor with a poor but variable prognosis. Our aim was to investigate the feasibility of MR perfusion imaging by using arterial spin-labeling for determining the prognosis of patients with glioblastoma.

Materials and methods: Pseudocontinuous arterial spin-labeling with 3D background-suppressed gradient and spin-echo was acquired before surgery on 53 patients subsequently diagnosed with glioblastoma. The calculated CBF color maps were visually evaluated by 3 independent readers blinded to patient history. Pathologic and survival data were correlated with CBF map findings. Arterial spin-labeling values in tumor tissue were also quantified by using manual fixed-size ROIs.

Results: Two perfusion patterns were characterized by visual evaluation of CBF maps on the basis of either the presence (pattern 1) or absence (pattern 2) of substantial hyperperfused tumor tissue. Evaluation of the perfusion patterns was highly concordant among the 3 readers (κ = 0.898, P < .001). Pattern 1 (versus pattern 2) was associated with significantly shorter progression-free survival by Kaplan-Meier analysis (median progression-free survival of 182 days versus 485 days, P < .01) and trended with shorter overall survival (P = .079). There was a significant association between pattern 1 and epidermal growth factor receptor variant III expression (P < .01).

Conclusions: Qualitative evaluation of arterial spin-labeling CBF maps can be used to stratify survival and predict epidermal growth factor receptor variant III expression in patients with glioblastoma.

Fig 1.

Qualitative and quantitative evaluation of ASL CBF maps. Conventional MR imaging (T1-weighted postcontrast imaging in A and E, T2 FLAIR in B, and T2 spin-echo in F) and ASL perfusion imaging (C and G) were visually evaluated by 3 independent readers. Two perfusion patterns can be characterized: Pattern 1 is characteristic of the presence of substantial hyperperfused tumor tissue in the CBF map, which can be identified by the bright ring-of-fire appearance (white arrows in C); in comparison, pattern 2 corresponds to the absence of easily recognizable hyperperfused tumor tissue compatible with a relatively less perfused tumor (G). Quantitative evaluation of ASL CBF maps is performed by applying manual ROIs in the tumoral regions with a ring-of-fire appearance and the mirrored regions in the contralateral hemisphere (D and H).

Fig 2.

The Kaplan-Meier curve and log-rank test for progression-free survival and overall survival. GBM perfusion patterns are examined in their relationship to PFS (A) and OS (B). The x-axis shows days after surgery (baseline) with the vertical lines noting 6- and 12-month PFS (A) and 6- and 12-month OS (B), respectively. The y-axis represents the percentage not progressed.