Predicting Glioblastoma Recurrence from Preoperative MR Scans Using Fractional-Anisotropy Maps with Free-Water Suppression.

Marie-Christin Metz,Jens Gempt,Miguel Molina-Romero,Lioba Grundl,Bjoern Menze,Jana Lipkova,Paul Eichinger,Claus Zimmer,Stephanie E Combs,Friederike Liesche-Starnecker,Benedikt Wiestler

doi:10.3390/cancers12030728

Abstract

Diffusion tensor imaging (DTI), and fractional-anisotropy (FA) maps in particular, have shown promise in predicting areas of tumor recurrence in glioblastoma. However, analysis of peritumoral edema, where most recurrences occur, is impeded by free-water contamination. In this study, we evaluated the benefits of a novel, deep-learning-based approach for the free-water correction (FWC) of DTI data for prediction of later recurrence. We investigated 35 glioblastoma cases from our prospective glioma cohort. A preoperative MR image and the first MR scan showing tumor recurrence were semiautomatically segmented into areas of contrast-enhancing tumor, edema, or recurrence of the tumor. The 10th, 50th and 90th percentiles and mean of FA and mean-diffusivity (MD) values (both for the original and FWC–DTI data) were collected for areas with and without recurrence in the peritumoral edema. We found significant differences in the FWC–FA maps between areas of recurrence-free edema and areas with later tumor recurrence, where differences in noncorrected FA maps were less pronounced. Consequently, a generalized mixed-effect model had a significantly higher area under the curve when using FWC–FA maps (AUC = 0.9) compared to noncorrected maps (AUC = 0.77, p < 0.001). This may reflect tumor infiltration that is not visible in conventional imaging, and may therefore reveal important information for personalized treatment decisions.

Highlights

Glioblastoma is the most aggressive primary brain tumor, with a median survival rate of only 15 months despite intensive treatment that usually consists of surgery and subsequent radiochemotherapy [1]
We identified a significant difference in free-water-corrected FA values in regions with later tumor recurrence and those of pure edema
FA values values of of regions regions with with later later tumor tumor recurrence recurrence significantly edema; areas of of later recurrence showed significantly lower significantlydiffered differedfrom fromthose thoseofofpure pure edema; areas later recurrence showed significantly lower values, comparable to values seen in contrast-enhancing tumors

Summary

Introduction

Glioblastoma is the most aggressive primary brain tumor, with a median survival rate of only 15 months despite intensive treatment that usually consists of surgery and subsequent radiochemotherapy [1]. Cancers 2020, 12, 728 the most fatal characteristics of glioblastomas is their ability to diffusely infiltrate the brain tissue, which leads to the commonly accepted assumption that contrast-enhancing tumor margins do not represent true tumor borders [2]. Most tumor recurrences occur in the peritumoral edema, whereas only about 10%. Much effort has been undertaken to identify means to assess nonenhancing peritumoral edema for tumor infiltration that is not visible in conventional imaging [4,5]. Tumor infiltration or invasion is characterized by a variable degree of anisotropy reduction. Peritumoral edema results in reduced anisotropy in white matter, which significantly hinders differentiation between pure edema and an actual tumor invasion [7]

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