Metabolic CEST MRI of glucosamine uptake in brain tumor-bearing mice

Increased reliance on anaerobic glycolysis is a hallmark of cancer metabolism that is traditionally used by FDG-PET for lesions and metastases detection. Glucose-based chemical exchange saturation transfer (glucoCEST) MRI offers an alternative, non-radioactive approach for characterizing metabolic changes. In this context, glucosamine (GlcN), a safe dietary supplement, has recently demonstrated favorable bio-distribution and contrast-enhancing properties suitable for cancer imaging both in rodents and in human subjects. However, results are currently limited to breast cancer and to healthy mouse brain. Here, we investigate the ability of CEST MRI to detect and characterize GlcN uptake in brain tumors in vivo. A GL261 glioma mouse model was imaged with a 7T scanner at baseline and at 8 and 16 minutes after intravenous GlcN administration. CEST contrast was quantified using the area under the magnetization transfer ratio asymmetry curve (MTRasym AUC) and multi-pool Lorentzian fitting. Sixteen minutes following GlcN injection, a statistically significant increase in the hydroxyls (OH) CEST signal was observed in the tumor region compared to the contralateral region (p = 0.0413, AUC; p = 0.0046, OH fitted Lorentzian amplitude). These findings suggest that GlcN-based CEST imaging may offer a biocompatible method for brain tumor characterization.