IMG-108. Dynamic Glucose Enhanced Imaging using Direct Water Saturation in Brain Tumors

BACKGROUND Dynamic glucose-enhanced (DGE)-MRI utilizes D-glucose as a biodegradable contrast agent, offering tissue contrast uptake information similar to dynamic contrast-enhanced (DCE)- and dynamic susceptibility contrast (DSC)-MRI. DGE leverages chemical exchange saturation transfer (CEST), enhancing sensitivity by detecting water signal reductions from low-concentration solutes. To mitigate DGE’s proneness to motion artifacts and enhance signal-to-noise ratio, we proposed to measure the linewidth (LW) increase of the direct water saturation (DS) Z-spectrum consequent to the increase in transverse relaxation (DS-DGE). We present DS-DGE data from glioma patients at 3T and compare with DCE-/DSC-derived hemodynamic parameters. METHODS Six patients (4 glioblastomas, 2 low-grade astrocytomas) were scanned at 3T (Philips Elition RX). After a D-glucose infusion (D50, 0.5g/kg [max 35 g], 6.25 g/min), DS-DGE-MRI was performed acquiring 40 dynamics (each with a DS Z-spectrum with 32 offset-frequencies) yielding a resolution of 2.2x2.2x4.4 mm³. A deep learning-based Lorentzian fit generated LW. Pre-infusion baseline (LWbase) and post-infusion (LWavg) values were calculated along with DS-DGE AUC (LWavg-LWbase)/LWbase). DCE-/DSC-MRI data were analyzed using extended Toft and leakage-corrected tracer models, respectively. Mean±STDev were obtained for DS-DGE AUC, leakage-corrected CBV, Ktrans, and Ve from ROIs in tumor and normal white matter (WM). RESULTS DS-DGE AUC was over two-fold higher in contrast-enhanced tumor (CE) versus WM (2.7±1.15% vs 1.29±0.51%). Regions with Edema and Necrosis had ~50% higher DS-DGE AUC than in WM. In comparison, leakage-corrected CBV in both CE and Necrosis was ~25% lower than WM while Edema was similar to WM. Ktrans and Ve were higher in CE compared to both Edema and Necrosis (0.056±0.025 min-1 (CE), 0.027±0.017 min-1 (Edema), 0.031±0.028 min-1 (Necrosis) for Ktrans and 0.12±0.081 (CE), 0.053±0.058 (Edema), 0.075± 0.085 (Necrosis) for Ve. CONCLUSIONS DS-DGE MRI effectively highlighted glioma and produced contrast metrics similar to or complementary to gadolinium-based DCE/DSC-MRI supporting its potential for non-gadolinium-based imaging using D-glucose.