Abstract
Background: Measuring optic nerve sheath diameter (ONSD), a relatively re-cent technique, allows an indirect and non-invasive diagnosis of intracranial hypertension. The ONSD ratio to eyeball transverse diameter (ETD) increases this reliability of the technique. The objective of this study was to determine the normal ONSD and its ratio with ETD in black African adults in Benin. Methods: A descriptive cross-sectional study was conducted between May 2019 and August 2019. Ultrasound ONSD and ONSD/ETD ratio were meas-ured in 210 healthy adults received in the medical imaging department of the Borgou and Alibori University Hospital Center in Benin. The ONSD corre-sponded to the average of 12 measurements (03 horizontal and 03 vertical for each eye) taken 3 mm behind the papilla. The transverse ETD corresponded to the average of 03 measurements. Results: The mean ONSD was 4.20 ± 0.28 mm (95% CI = [4.17; 4.24] mm and 95th percentile = 4.70 mm). The mean ETD was 24.25 ± 1.10 mm. The ONSD/ETD ratio was 0.17 ± 0.01 (95% CI = [0.17; 0.17] and 95th percentile = 0.19). There was no difference between ver-tical and horizontal ONSD and between right and left ONSD. The ONSD and the ONSD/ETD ratio were not correlated with any of the socio-demographic and anthropometric characteristics studied (sex, age, ethnicity, weight, height, body mass index, head circumference and waist circumference). The ONSD was associated with ETD (p < 0.001 and r = 0.55). Conclusion: An ONSD and an ONSD/ETD ratio respectively greater than 4.70 mm and 0.19 should sus-pect intracranial hypertension. The ONSD/ETD ratio may be a better indicator of HICT because of its small variation.
Highlights
Intracranial hypertension (ICH) is one of the major causes of mortality and neurological sequelae in neuro-intensive care [1]
Ultrasound optic nerve sheath diameter (ONSD) and ONSD/eye transversal diameter (ETD) ratio were measured in 210 healthy adults received in the medical imaging department of the Borgou and Alibori University Hospital Center in Benin
Recent studies noted that the association of eye transversal diameter (ETD) measuring through the ONSD/ETD ratio improves the technique’s reliability in intracranial hypertension diagnosis [14] [15] [16]
Summary
Intracranial hypertension (ICH) is one of the major causes of mortality and neurological sequelae in neuro-intensive care [1]. Its reference diagnosis method is the intracranial pressure (ICP) monitoring with intra-ventricular or intra-parenchymal sensors [2] This invasive technique, with possible infectious and/or bleeding complications, is often not available in low and middle incomes countries like Benin. Neuroimaging techniques such as computed tomography (CT), magnetic resonance imaging (MRI) and transcranial Doppler ultrasound allow a non-invasive diagnosis [2] [3] [4]. Recent studies noted that the association of eye transversal diameter (ETD) measuring through the ONSD/ETD ratio improves the technique’s reliability in intracranial hypertension diagnosis [14] [15] [16]. The efficient use of this technique in the benefit of our populations in Benin, where ultrasound is one of the most accessible imaging techniques, requires the prior sonographic determination of normal ONSD and ONSD/ETD ratio values, which is the objective of the present study
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
