Hamid Shokoohi1, Matthew Pyle2, Evan Kuhl2, Michael A Loesche3, Aakshit Goyal4, Maxine A LeSaux2, Keith S Boniface2, M Reza Taheri4. 1. Department of Emergency Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA. 2. Department of Emergency Medicine, The George Washington University Medical Center, Washington, DC. 3. Harvard Affiliated Emergency Medicine Residency Program, Harvard Medical School, Boston, MA. 4. Department of Radiology, The George Washington University Medical Center, Washington, DC.
Abstract
BACKGROUND AND PURPOSE: Ultrasound (US) measurement of the optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) is a method frequently used to screen for an increased intracranial pressure. The aim of this study was to assess the accuracy of US measurements of ONSD and OND, when compared to magnetic resonance imaging (MRI) measurements as the criterion standard. METHODS: In this prospective, single-institution study, orbital US was performed for those patients requiring an emergent brain MRI. ONSD and OND of both eyes were measured in the axial and coronal planes in straight gaze by US. ONSD and OND from brain and orbital MRI were measured by two neuroradiologists. Correlation and agreement between readings were assessed using Pearson's correlations. RESULTS: Eighty-two patients met inclusion criteria. The mean axial and coronal ONSD in the MRI examinations was 5.6 and 5.7 mm at 3-5.9 mm behind the globe, respectively. The mean ONSD from the US measurements was 6.22 and 5.52 mm in the axial and coronal planes, respectively. The mean OND in US examinations was 4.31 mm (axial) and 3.68 mm (coronal). Axial versus coronal measurements of ONSD had a modest correlation in US assessment with an r2 of .385 (P < .001) but there were no correlations between any of the US and MRI measurements. CONCLUSIONS: In measuring ONSD and OND, US measurements showed a modest correlation between axial and coronal measurements, but no concordance was found between US and MRI in our setting.
BACKGROUND AND PURPOSE: Ultrasound (US) measurement of the optic nerve sheath diameter (ONSD) and optic nerve diameter (OND) is a method frequently used to screen for an increased intracranial pressure. The aim of this study was to assess the accuracy of US measurements of ONSD and OND, when compared to magnetic resonance imaging (MRI) measurements as the criterion standard. METHODS: In this prospective, single-institution study, orbital US was performed for those patients requiring an emergent brain MRI. ONSD and OND of both eyes were measured in the axial and coronal planes in straight gaze by US. ONSD and OND from brain and orbital MRI were measured by two neuroradiologists. Correlation and agreement between readings were assessed using Pearson's correlations. RESULTS: Eighty-two patients met inclusion criteria. The mean axial and coronal ONSD in the MRI examinations was 5.6 and 5.7 mm at 3-5.9 mm behind the globe, respectively. The mean ONSD from the US measurements was 6.22 and 5.52 mm in the axial and coronal planes, respectively. The mean OND in US examinations was 4.31 mm (axial) and 3.68 mm (coronal). Axial versus coronal measurements of ONSD had a modest correlation in US assessment with an r2 of .385 (P < .001) but there were no correlations between any of the US and MRI measurements. CONCLUSIONS: In measuring ONSD and OND, US measurements showed a modest correlation between axial and coronal measurements, but no concordance was found between US and MRI in our setting.