New Optic Nerve Sonography Quality Criteria in the Diagnostic Evaluation of Traumatic Brain Injury

Abstract

Background New sonographic quality criteria to optimize optic nerve sheath diameter (ONSD) measurements were suggested. The latter were correlated to elevated intracranial pressure (ICP) in traumatic brain injury (TBI). Aim We investigated whether ONSD measurements were correlated to simultaneous ICP measurements in severe TBI. Methods Forty patients with severe TBI (Marshall Scale ≥II and GCS ≤8) participated in the study. All patients had an intraparenchymal ICP catheter inserted, while ONSD was measured bilaterally, upon admission and over the next 48 hours, based on the new sonographic criteria. A total of 400 ONSD measurements were performed, while mean ONSD values of both eyes were used in the analysis. Results ONSD measurements were strongly correlated to ICP values (r=0.74, p < 0.0001). Receiver operator curve (ROC) analysis revealed that the ONSD cutoff value for predicting elevated ICP was 6.4 mm when using the mean of both eyes (AUC = 0.88, 95% CI = 0.80 to 0.95; sensitivity = 85.3%, specificity = 82.6%). Linear regression analysis nested models revealed that sex (p=0.006) and height (p=0.04) were significant predictors of ONSD values. Conclusion When applying the new sonographic quality criteria, ONSD is strongly correlated to ICP in severe TBI. Whether to use such criteria to monitor ONSD as a proxy for ICP trend in TBI remains to be further explored.

A New Inexpensive Simulation Model for Ultrasound Assessment of Optic Nerve Sheath Diameter

“…31 Early data suggest that these criteria may lead to a change in normal values for ONSD measurement. 9 These criteria emphasize bilateral ocular sonography and avoidance or identification of landmarks within and around the globe, which are not simulated in our model. To our knowledge, no model to date has been developed which is able to simulate all structures necessary to apply the new quality criteria.…”

“…This black line is the optic nerve, and its diameter is measured 3 mm behind the optic disc (Figure 3). [7][8][9]22,23 Measurements were conducted by three expert point-of-care ultrasonographers (LG, TJ, AD) in a single session. The diameters were 3.5 mm (polyvinyl intravenous line tubing), 4 mm (nasogastric tube), 4.2 mm (spring wire guide sheath), 4.6 mm (nasogastric tube), 5.5 mm (nasogastric tube), 6 mm (tracheostomy cannula), and 7.9 mm (nasogastric tube).…”

“…6 Acute increases in ICP have been shown to strongly correlate with increases in ONSD. [7][8][9][10] Recently, ultrasound measurement of ONSD has been investigated for use as a dynamic real-time ICP monitoring tool in critically ill patients with promising results. 10 Ultrasound itself is becoming increasingly available due to decreasing costs, the production of portable pocket ultrasound systems, and the dissemination of ultrasound expertise.…”

Validity and reliability of pocket-sized ultrasound devices in measurement of optic nerve sheath diameter in ICU patients

“…The ONSD measurement was performed according to the new Optic Nerve Sonography Quality Criteria. [8]. While recording proper images for measurement, we considered the following matters: clear discrimination of optic nerve, internal and external border of the subarachnoid space; capturing close proximity of the hypoechogenic regions which belong to optic nerve fibers and vitreous fluid inside the eye globe and lens-free images.…”

“…Optic nerve sheath is anatomically continuous with dura mater, and optic nerve, pia mater and subarachnoid space can be distinguished easily with proper technique [7]. Ultrasonographic images should be obtained with appropriate techniques according to new Optic Nerve Sonography Quality Criteria [8]. Recent studies suggest that daily monitoring of ONSD measurement by USG can be useful not only for the determination of increased ICP but also for evaluating the neurological prognosis of the patients [9][10][11].…”