fig 4.

Ring-enhancing lesion surrounded by edema (arrows) and multiple non-active lesions. Proton density–weighted (2060/20/1) (A), postcontrast T1-weighted (510/14/2) (B), k_for (C), and T1_free (D) images. The quantitative analysis in the acute lesions yielded the following results: ring-enhancing lesion: MTR = 16.4 %, k_for = 0.13 s⁻¹, T1_free = 1.5 s; edema: MTR = 41.1 %, k_for = 0.56 s⁻¹, T1_free = 1.2 s. Proton density–weighted (E) and postcontrast T1-weighted (F) images acquired 6 weeks later. Disappearance of perifocal signal abnormality supports the assumption of edema