Diagnostic Performance of Arterial Spin Labeling for Grading Nonenhancing Astrocytic Tumors

抄録

Purpose: We evaluated the utility of arterial spin labeling (ASL) imaging of tumor blood flow (TBF) for grading non-enhancing astrocytic tumors.

Materials and Methods: Thirteen non-enhancing astrocytomas were divided into high-grade (n = 7) and low-grade (n = 6) groups. Both ASL and conventional sequences were acquired using the same magnetic resonance machine. Intratumoral absolute maximum TBF (TBF_max), absolute mean TBF (TBF_mean), and corresponding values normalized to cerebral blood flow (TBF_max and TBF_mean ratios) were measured. The Mann-Whitney U test and receiver operating characteristic (ROC) curve analysis were used to assess the accuracy of TBF variables for tumor grading.

Results: Compared with low-grade astrocytoma, high-grade astrocytoma exhibited significantly greater absolute TBF_max (90.93 ± 24.96 vs 46.94 ± 20.97 ml/100 g/min, P < 0.001), TBF_mean (58.75 ± 19.89 vs 31.16 ± 17.63 ml/100 g/min, P < 0.001), TBF_max ratio (3.34 ± 1.22 vs 1.35 ± 0.5, P < 0.001), and TBF_mean ratio (2.15 ± 0.94 vs 0.88 ± 0.41, P < 0.001). The TBF_max ratio yielded the highest diagnostic accuracy (sensitivity 100%, specificity 86.3%), while absolute TBF_mean yielded the lowest accuracy (sensitivity 85.7%, specificity 70.1%) by ROC analysis.

Conclusion: Parameters from ASL perfusion imaging, particularly TBF_max ratio, may be useful for distinguishing high-grade from low-grade astrocytoma in cases with equivocal conventional MRI findings.