Role of Ocular Ultrasonography to Distinguish Papilledema From Pseudopapilledema

We prospectively evaluated the sensitivity and specificity of ocular ultrasonography (OUS) to distinguish papilledema from pseudopapilledema.

Forty-nine study participants, with optic disc elevation, underwent neuro-ophthalmic evaluation, OUS, fundus photography, and optical coherence tomography (OCT) of the optic nerve head at the initial and follow-up visits (≤6 months apart). Participants were classified as having papilledema if there was a change in optic nerve appearance on fundus photographs, as determined by a masked observer, between initial and follow-up visits ≤6 months apart. OUS was considered positive when the optic nerve sheath width was >3.3 mm and the 30° test was positive. Ocular ultrasonographic findings were correlated in patients who had papilledema vs patients who had pseudopapilledema. In a subanalysis, OUS findings were also correlated with change in peripapillary retinal nerve fiber layer thickness on OCT of the optic nerve head between initial and follow-up visits.

OUS was 68% (17/25) sensitive for papilledema and 54% (13/24) specific for pseudopapilledema. When using OCT parameters to define papilledema, the sensitivity of OUS to diagnose papilledema decreased to 62%. Positive OUS correlated with elevated opening pressure on lumbar puncture and with signs of increased intracranial pressure on MRI.

OUS alone was less sensitive in diagnosing papilledema than previously thought. Therefore, OUS may not be helpful in distinguishing between papilledema and pseudopapilledema.