Correlation of optic nerve sheath diameter measurements by computed tomography and magnetic resonance imaging

• Published in: The American journal of emergency medicine Vol. 31; no. 11; pp. 1595 - 1597
• Main Authors: Kalantari, Hossein, MD, MPH, Jaiswal, Rajnish, MD, Bruck, Isaac, MD, PhD, Matari, Hussein, MD, Ghobadi, Farzaneh, MD, Weedon, Jeremy, PhD, Hassen, Getaw Worku, MD, PhD
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.11.2013; Elsevier Limited
• Subjects: Age; Agreements; Computed tomography; Confidence intervals; Emergency; Emergency medical care; Female; Humans; Intracranial Pressure; Magnetic Resonance Imaging; Male; Measurement techniques; Medical imaging; Middle Aged; NMR; Nuclear magnetic resonance; Optic Nerve - anatomy & histology; Optic Nerve - diagnostic imaging; Retrospective Studies; Tomography; Tomography, X-Ray Computed; Ultrasonic imaging
• ISSN: 0735-6757; 1532-8171
• DOI: 10.1016/j.ajem.2013.07.028

Abstract Background Traditionally, intracranial pressure is measured by direct ventriculostomy, which is invasive. Noninvasive measures such as bedside ultrasound and magnetic resonance imaging have been advocated and utilized recently to assess the intracranial pressure. The role of this study is to determine the degree of agreement between measurements of the optic nerve sheath diameter by computed tomography (CT) and magnetic resonance imaging (MRI). Materials and Methods Retrospective chart review of 100 consecutive patients who had both MRI and CT scan of the head from January 1, 2011, until March 31, 2013, at our center was performed. A discrepancy of 0.2 mm between the 2 measurements was set as acceptable difference. The measurements of optic nerve sheath diameter (ONSD) were compared for agreement between the 2 modalities using the method by Bland and Altman. Results A total of 100 patients with both MRI and CT scan of the head were selected. Of these 100 patients, 24 were male and 76 were female. The average age was 63 years. No ONSD abnormality was detected in any of the patients. The discrepancy in measurements of the ONSD between CT and MRI in transverse plane was less than the predetermined cut-off value of 0.2 mm. Within-subject variance was estimated at 0.0058 for both CT and MRI. Conclusion Comparable results without significant discrepancy as predetermined by the study groups were obtained from CT scan. Measurement of ONSD by CT scan can be used to indirectly asses the intracranial pressure in addition to clinical assessment and other signs of increased intracranial pressure on CT scan.