Optic nerve sheath diameter measurement techniques: Examination using a novel ex-vivo porcine model

Derek M. Nusbaum*, Erik Antonsen, Kurt H. Bockhorst, R. Blaine Easley, Jonathan B. Clark, Kenneth Martin Brady, Kathleen K. Kibler, Jeffrey P. Sutton, Larry Kramer, Ashot E. Sargsyan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Scopus citations


Background: Ultrasound (U/S) and MRI measurements of the optic nerve sheath diameter (ONSD) have been proposed as intracranial pressure measurement surrogates, but these methods have not been fully evaluated or standardized. The purpose of this study was to develop an ex-vivo model for evaluating ONSD measurement techniques by comparing U/S and MRI measurements to physical measurements. Methods: The left eye of post mortem juvenile pigs ( N 5 3) was excised and the subdural space of the optic nerve cannulated. Caliper measurements and U/S imaging measurements of the ONSD were acquired at baseline and following 1 cc saline infusion into the sheath. The samples were then embedded in 0.5% agarose and imaged in a 7 Tesla (7T) MRI. The ONSD was subsequently measured with digital calipers at locations and directions matching the U/S and direct measurements. Results: Both MRI and sonographic measurements were in agreement with direct measurements. U/S data, especially axial images, exhibited a positive bias and more variance (bias: 1.318, 95% limit of agreement: 8.609) compared to MRI (bias: 0.3156, 95% limit of agreement: 2.773). In addition, U/S images were much more dependent on probe placement, distance between probe and target, and imaging plane. Conclusions: This model appears to be a valid test-bed for continued scrutiny of ONSD measurement techniques. In this model, 7T MRI was accurate and potentially useful for in-vivo measurements where direct measurements are not available. Current limitations with ultrasound imaging for ONSD measurement associated with image acquisition technique and equipment necessitate further standardization to improve its clinical utility.

Original languageEnglish (US)
Pages (from-to)50-54
Number of pages5
JournalAviation Space and Environmental Medicine
Issue number1
StatePublished - Jan 2014


  • Intracranial pressure
  • Magnetic resonance imaging
  • Optic nerve sheath diameter
  • Ultrasound

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health


Dive into the research topics of 'Optic nerve sheath diameter measurement techniques: Examination using a novel ex-vivo porcine model'. Together they form a unique fingerprint.

Cite this