Glutamine Imaging: A New Avenue for Glioma Management

¹H- and ¹³C-MR spectra of healthy brain and glioma tissue. A, ¹H-MR spectrum acquired at 7T using a 3D MR spectroscopic imaging sequence in a healthy human volunteer. Glutamine and glutamate peak fits are shown in blue and pink, respectively, demonstrating separation at 7T. B, Structural MP2RAGE image and glutamine metabolite map acquired in the same subject as in A. The Color bar shows metabolite concentrations in arbitrary units. C, Structural MP2RAGE image and a glutamine metabolite map acquired in a male patient with glioblastoma (51 years of age). The Color bar shows metabolite concentrations in arbitrary units. Glutamine concentrations are increased in the tumor region, indicated by the dark mass in the MP2RAGE image, relative to the rest of the brain. A–C adapted and reprinted with permission from Hingerl et al.²² D, ¹³C-MR spectrum acquired in a healthy mouse brain at 14.1T after 3 hours of infusion with [1,6-¹³C]-glucose. E, ¹³C-MR spectrum acquired from a tumor-bearing mouse brain after 3 hours of infusion of [1,6-¹³C]-glucose. Decreased glutamate peak intensities (carbon [C]2, C3, and C4) and glutamine peak intensities (C2, C3, and C4) are observed compared with healthy brain without tumor (blue arrows). D and E adapted and reprinted with permission from Lai et al.³⁰ Ala indicates alanine; Asp, aspartate; GABA, γ-aminobutyric acid; Glc, glucose; Gln, glutamine; Glu, glutamate; Lac, lactate; NAA, N-acetylaspartate.