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

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.

Analyzing the effects of free water modeling by deep learning on diffusion MRI structural connectivity estimates in glioma patients

“…Thus, the reduction of tracts several standard deviations away from the mean is a sign of noise reduction. Meanwhile, the observed increase of the single-tract CoV using probabilistic tractography in patients further indicates the potential of the FWM to improve differentiation of white matter microheterogeneity by demasking free water partial volume effects obscuring true white matter alterations in edema, which is further supported by recent findings [39].…”

Multiparametric MRI assessment of response to convection-enhanced intratumoral delivery of MDNA55, an interleukin-4 receptor targeted immunotherapy, for recurrent glioblastoma

“…[ 11 ] However, advanced MRI techniques such MR spectroscopy, diffusion, and perfusion MRI have been used successfully for determining prognosis, predicting, and assessing treatment response to different therapeutic regimens in these patients. [ 1 , 2 , 6 , 10 , 13 , 19 , 22 , 28 - 30 , 32 , 33 ] On DTI, successful treatment is exhibited by increase in MD, and decrease in FA values reflecting destruction of tumor cells and reduction of barriers to proton motion. [ 5 , 20 , 21 , 32 ] From our case, we observed large % decreases (33–37%) in FA at follow-up periods relative to baseline indicating favorable treatment response.…”

Effects of Multi-Shell Free Water Correction on Glioma Characterization

“…The DWI signal decay in both ventricles and the two most cystic necrotic volumes was found to be normal, and FW was estimated to one in both cases. It is possible that FW correction methods, such as the one applied in this study, can be of value in differentiating true disease progression from pseudo-progression [ 44 ]. Tumor cellularity, as derived with RSI, has been presented as a possible diagnostic tool in identifying pseudo-progression in glioblastoma [ 45 , 46 ].…”