Purchase this article with an account.
S. Bose, T. McCulley, M. Taban, J. Fallon, S. Potkin; PET Scan Changes Following Optic Nerve Sheath Fenestration for Pseudotumor Cerebri . Invest. Ophthalmol. Vis. Sci. 2003;44(13):2725.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Background. The mechanism by which optic nerve sheath fenestration (ONSF) improves visual function is still under debate. To date, there has not been any comprehensive functional neuroimaging study that provides information regarding metabolic changes in the brain in patients with pseudotumor cerebri (PTC) before and after ONSF. Objectives: To describe changes in the glucose metabolic rate of the brain and anterior visual pathways following ONSF using positron emission tomography (PET) scanning. Methods: A 19-year-old obese white female diagnosed with PTC presented with a severe visual loss in her right eye to light perception, 20/25 OS, bilateral disc edema; normal Brain CT and MRI, and a CSF opening pressure of 350 mm H2O with normal cytology. A PET scan with fluoride-18 fluorodeoxyglucose (FDG) was performed. The patient underwent ONSF of the right eye via a medial approach and she underwent repeat FDG PET scanning on post-operative day 8; her VA improved to 20/25 OD. Results: Presurgery, the PET scan revealed dramatic bilateral metabolic changes compared with 56 controls. However, the primary (BA 17) and proximal (BA 18,19) visual cortices do not show any differences, except in BA 19 in the dorsal visual stream. Postsurgery, relative to the visual system, significant bilateral increases in uptake along the path of the optic nerves, optic radiations and in most of occipital, temporal, parietal visual processing system were observed. Although the differences noted presurgery in the non-primary visual areas of the brain remain, or even accentuated, the presurgery hypermetabolism in primary visual cortex appear to have been reversed by the surgery. Conclusion: Metabolic imaging with FDG-PET provides functional information not attainable with MRI, MRA, or MR spectroscopy since PTC patients, as in this case, can have abnormal PET studies despite normal conventional neuroimaging. ONSF or a reduction in ICP appears to reverse the GMR in the dorsal and ventral visual streams.
This PDF is available to Subscribers Only