Fig. 4

5-year-old boy with NF-I. a. Axial T2W MR image of the orbits shows bilateral ONG (dashed arrows) causing fusiform enlargement and kinking of the optic nerves. A focal T2- hyperintense lesion (arrowhead) is seen in the right mesial temporal lobe. b. Coronal T2WMR image of the same patient shows extension of the bilateral ONG along the intracranial segments of the optic nerves (arrows). c. Axial contrast-enhanced FS TIW MR image of the same patient shows prominent enhancement in the intracanalicular and intracranial segments of bilateral ONG (arrows). There is also avid enhancement in the suprasellar/chiasmatic region (arrowhead) and in the right mesial temporal lesion (arrowhead) in keeping with tumour extension along the optic chiasm and right optic radiation