Fig 9. A 17-year-old boy with right papilledema and orbital pain and rule out pseudotumor. The patient had positive serum EIA and Western blot (IgM and IgG) and CSF Lyme IgM and IgG antibodies. Lyme PCR in the CSF was negative. Complete resolution of symptoms occurred after intravenous ceftriaxone therapy. Right optic nerve edema on fat-saturated T2-weighted fast spin-echo images (A) and right-greater-than-left optic nerve enhancement on coronal fat-saturated contrast-enhanced T1-weighted images (B). C, Bilateral third cranial nerve enhancement (arrowheads) and bilateral retrobulbar compartment congestion (arrow). Note the generalized extraocular muscle enlargement and enhancement, including the insertions. Additional imaging findings included enhancement of right fifth cranial nerve, optic chiasm, and intracanalicular right seventh nerve, all of which were occult to neurologic examination.