ABSTRACT Background Glutamate chemical exchange saturation transfer (GLU‐CEST) is a non‐invasive in vivo approach for glutamate detection, but its performance for glioma evaluation at 5T remains incompletely defined. Purpose To investigate factors influencing 5T GLU‐CEST and its diagnostic value in glioma stratification. Study Type Prospective. Phantom and Population Five phantom series (pH 6.2–7.4; glutamate 8–20 mM) and 40 adult‐type diffuse glioma patients (49.00 ± 12.26 years; 23 males). Fieldstrength/Sequence 5 T, fast spin‐echo GLU‐CEST and amide proton transfer (APT)‐CEST. Assessment Phantoms and patients underwent MRI scans; GLU‐CEST, APT‐CEST, and normalized values (ΔGLU‐CEST, ΔAPT‐CEST) were quantified. Gliomas were graded by WHO 2–4; IDH status was determined. Statistical Tests Spearman correlation, Kruskal–Wallis tests, Mann–Whitney U tests, and weighted DeLong tests; two‐sided p < 0.05 was significant. Results GLU‐CEST signals positively correlated with glutamate and negatively with pH ( ρ ≥ 0.893). Significant differences were found in all effects between WHO Grade 2 and 4 gliomas (ΔGLU‐CEST: 2.006 1.143, 2.799 vs. 4.365 2.974, 5.299; GLU‐CEST: 7.424 6.679, 7.649 vs. 10.155 8.098, 11.550; ΔAPT‐CEST: 1.918 1.258, 2.461 vs. 3.386 2.682, 4.805; APT‐CEST: 1.961 1.425, 2.715 vs. 3.333 2.478, 4.632), whereas only ΔGLU‐CEST and GLU‐CEST exhibited significant disparities between Grade 3 and 4 gliomas (ΔGLU‐CEST: 2.171 1.895, 2.862 vs. 4.365 2.974, 5.299; GLU‐CEST: 7.102 6.475, 7.259 vs. 10.155 8.098, 11.550). In the solid tumor region, all effects demonstrated significant differences between IDH‐mutant and IDH wild‐type gliomas (ΔGLU‐CEST: 2.111 1.614, 3.110 vs. 4.333 2.964, 5.405; GLU‐CEST: 7.259 6.577, 7.726 vs. 10.291 8.097, 11.634; ΔAPT‐CEST: 2.017 1.355, 2.718 vs. 3.235 2.670, 4.735; APT‐CEST: 2.122 1.680, 2.889 vs. 3.270 2.450, 4.262), whereas GLU‐CEST outperformed APT‐CEST and ΔAPT‐CEST in diagnostic efficacy (AUC difference = 0.073 and 0.101). Data Conclusion 5 T GLU‐CEST is capable of differentiating between grade 2 and grade 4, as well as grade 3 and grade 4 adult diffuse gliomas, and demonstrates superior performance to APT‐CEST in the classification of IDH status. Evidence Level 2. Technical Efficacy Stage 2.
Ying et al. (Sun,) studied this question.