Value of Early Postoperative FLAIR Volume Dynamic in Glioma with No or Minimal Enhancement

Abstract

Objective: The evaluation of postoperative magnetic resonance imaging (MRI) in glioma with no or minimal enhancement is controversial because the evaluation of residual tumor volume can be biased. The purpose of this study was to clarify the value of early postoperative and 3-month MRI regarding its validity in predicting recurrent disease.

Methods: For this retrospective, single-center study, overall fluid attenuated inversion recovery (FLAIR) volumes (early postoperative [<48 hours] and 3-month MRI including FLAIR and T1-weighted sequences with and without contrast agent) of 99 patients were assessed using manual segmentation. FLAIR volume dynamic over the first 3 months after surgery and its effect on disease recurrence were evaluated while considering histopathologic features.

Results: Overall FLAIR-hyperintense volume significantly decreased between early postoperative and 3-month follow-up MRIs (P < 0.001). Early FLAIR volume increase had a high positive predictive value for overall disease recurrence after resection (85.71% [95%-CI: 62.64-96.24]). Early FLAIR volume dynamic (P < 0.001), isocitrate dehydrogenase 1/2 status (P = 0.002), and preoperative Karnofsky Performance Status (P = 0.012) were observed as independent factors for progression-free survival in multivariate analysis.

Conclusion: Early postoperative FLAIR volume assessment in gliomas with no or minimal enhancement is susceptible to a systematic overestimation of residual tumors. Nevertheless, early FLAIR volume dynamic is an independent factor for tumor recurrence that should be evaluated in order timely adapt surveillance and therapy regimens accordingly.

Keywords: Early postoperative MRI; Low-grade glioma; No enhancement.