Longitudinal MR Spectroscopic Imaging of Pediatric Diffuse Pontine Tumors to Assess Tumor Aggression and Progression

(A) The region of excitation or PRESS box (white) and the phase-encoding matrix (green) for the MR spectroscopic imaging data acquisition are superimposed on an axial FLAIR MR image of patient 1 at baseline. The region of excitation encompasses the lesion (region of hyperintensity on the FLAIR image) and surrounding normal-appearing tissue. (B) Proton spectrum from a voxel in the tumor area (red box) of patient 1 at baseline. (C) Proton spectrum from a voxel in the normal-appearing tissue area (blue box) of patient 1 at baseline. (D) Proton spectrum obtained at follow-up 1 from the same voxel of origin for the spectrum shown in B.

Zoomed 2 × 3 array of proton spectra (A) collected at follow-up 1 from the tumor region of patient 1, where MR imaging contrast enhancement was observed (B).