Ganglioglioma. The neoplasia of a 49-year-old patient (ID no. 2, On-line Table 1) affects the left thalamus, pallidum, and putamen, and is characterized by a largely homogeneous elevated T2-FLAIR signal (A) and somewhat rim-like contrast enhancement (B). Based on 1H-MR imaging, differential diagnostic considerations included low-grade tumors such as GG and PA but also malignant neoplasias such as GB and cerebral metastasis. Na-MR imaging reveals a mean NaR:NaT of 1.39 (whole tumor VOI) and 1.26 (CE tumor VOI) (C and D) compatible with a low-grade tumor (Fig 3A, -B; On-line Fig 2E, -F; On-line Table 1). Thus, the differential diagnoses of GB and M could be ruled out. This result was confirmed by histopathology (On-line Fig 8). Na images are overlaid on T1-weighted postcontrast images; color mesh grid: whole tumor VOI, solid color: CE tumor VOI.