Bimedial rectus hypermetabolism in convergence spasm as observed on positron emission tomography.
A 52-year-old man developed vertical gaze palsy, convergence spasm, and convergence-retraction nystagmus due to glioblastoma of the right thalamus. 18F-fluorodeoxyglucose positron emission tomography (PET) inadvertently demonstrated markedly increased metabolism in the medial rectus muscles. The hypermetabolism indicates active contraction of these extraocular muscles due to excessive convergence drive attributed to inappropriate activation or disrupted inhibition of convergence neurons by the diencephalic lesion.
Jeong
Seong-Hae
SH
Department of Neurology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seoul, Korea.
Oh
Young-Mi
YM
Kim
Chae-Yong
CY
Kim
Ji Soo
JS