Reproducibility and accuracy of optic nerve sheath diameter assessment using ultrasound compared to magnetic resonance imaging

Abstract

BackgroundQuantification of the optic nerve sheath diameter (ONSD) by transbulbar sonography is a promising non-invasive technique for the detection of altered intracranial pressure. In order to establish this method as follow-up tool in diseases with intracranial hyper- or hypotension scan-rescan reproducibility and accuracy need to be systematically investigated.MethodsThe right ONSD of 15 healthy volunteers (mean age 24.5 ± 0.8 years) were measured by both transbulbar sonography (9 – 3 MHz) and 3 Tesla MRI (half-Fourier acquisition single-shot turbo spin-echo sequences, HASTE) 3 and 5 mm behind papilla. All volunteers underwent repeated ultrasound and MRI examinations in order to assess scan-rescan reproducibility and accuracy. Moreover, inter- and intra-observer variabilities were calculated for both techniques.ResultsScan-rescan reproducibility was robust for ONSD quantification by sonography and MRI at both depths (r > 0.75, p ≤ 0.001, mean differences < 2%). Comparing ultrasound- and MRI-derived ONSD values, we found acceptable agreement between both methods for measurements at a depth of 3 mm (r = 0.72, p = 0.002, mean difference < 5%). Further analyses revealed good inter- and intra-observer reliability for sonographic measurements 3 mm behind the papilla and for MRI at 3 and 5 mm (r > 0.82, p < 0.001, mean differences < 5%).ConclusionsSonographic ONSD quantification 3 mm behind the papilla can be performed with good reproducibility, measurement accuracy and observer agreement. Thus, our findings emphasize the feasibility of this technique as a non-invasive bedside tool for longitudinal ONSD measurements.

Optic Nerve Sheath Diameter for Preterm Infants: A Pilot Study

“…This has corroborated the accuracy of ultrasonography measurements in other studies with older patients [27, 28]. The obvious advantage that ultrasonography has over MRI is its allowance for rapid clinical decision making in urgent situations and serial evaluations for unknown pathophysiologic trajectories without transferring an unstable patient to a distant magnet.…”

Cerebral Vascular Control and Metabolism in Heat Stress

“…Direct and invasive measures of ICP (e.g., with craniotomy) are impractical in the healthy human experimental design. However, several indirect measures of ICP are readily attainable [e.g., lumbar CSF pressures, ocular pressure, optic nerve sheath diameter measures by transbulbar sonography, or MRI (38)]. Combining these during heat stress (while controlling for MAP and PaCO 2 ) will provide insight into changes in ICP-and indirectly to the increases in BBB permeability and cerebral water content.…”

Transorbital Sonography in Acute Optic Neuritis: A Case-Control Study

“…A procedure described previously in the literature was used. 14,15 Subjects were examined in the supine position with the upper part of the body and the head elevated to 20°-30°to avoid any pressure on the eye and were asked to keep their eyes in a midposition and to suppress eye movements. For safety reasons due to possible biomechanical side effects, the mechanical index was reduced to 0.2.…”

“…13 Previous studies did demonstrate good accuracy and reliability of sonographic quantification of optic nerve sheath diameter (ONSD). 14,15 The primary aim of this study was to use TOS to assess enlargement of the optic nerve and its sheath in acute ON by measuring optic nerve diameter (OND) and ONSD. The second aim was to identify whether OND and ONSD values were associated with any VEP abnormalities in cases of acute ON.…”