Figure 1
Longitudinal MRI studies of the orbitae. (a) Initial diagnosis of the left-orbital rhabdomyosarcoma with infiltration of the ethmoidal air cells and the left maxillary sinus (coronal and transversal contrast-enhanced fat-saturated T1w). (b) Normal post-therapeutic follow-up study. (c) At onset of double vision, discrete thickening of the left medial and inferior rectus muscle in the coronal T1w and of the left lateral rectus muscle in the ADC-map (arrow) became apparent, yet without pathological decrease in diffusivity (ADC = 1.25 x10−3 mm2/s). (d) Follow-up MRI showed progressive signal alterations in all left extraocular eye muscles and initial changes in the right medial rectus muscle. Both left and right medial rectus muscle showed significantly restricted diffusion (arrow, ADC = 0.62 x10−3 mm2/s). Figures 1b,c,d show coronal contrast-enhanced T1w and ADC-maps calculated from transversal DWI with b-values of 0 and 1000 s/mm2. The examinations were performed at 1.5 Tesla (1a and 1d) and at 3 Tesla (1b and 1c).