Ocular ultrasonography to detect intracranial pressure in aneurysmal subarachnoid hemorrhage

Optic Nerve Ultrasound Evaluation in Children: A Review

Managing patients with neurocritical illness requires monitoring and treating elevated intracranial pressure (ICP), especially in cases in children. In terms of precise and real-time measurements, invasive ICP measurements are presently the gold standard for the initial diagnosis and follow-up ICP assessments. As a rapid and non-invasive way to detect elevated ICP, point-of-care ultrasonography (POCUS) of optic nerve sheath diameter (ONSD) has been proposed. The utility of bedside POCUS of ONSD to detect elevated ICP with excellent diagnostic test accuracy in adults has already been demonstrated. Nonetheless, data on the relationship between POCUS of ONSD and ICP in children are scarce. Therefore, the purpose of this review is to point out the most recent findings from the pediatric published literature and briefly discuss what was assessed with ONSD ultrasound examination, and also to describe and discuss the diagnostic procedures available for optic nerve ultrasound appraisal. A search of the medical databases PubMed and Scopus was carried out. The terms such as "ocular ultrasonography", "ICP assessment", "children", "point-of-care ultrasound", and "POCUS" were searched. In conclusion, the use of the standardized A-scan technique coupled with the B-scan technique should be suggested to provide data that are as accurate, precise, repeatable, and objective as possible.

Optic Nerve Changes Detected with Ocular Ultrasonography during Different Surgical Procedures: A Narrative Review

Ultrasonographic appraisal of the optic nerve sheath diameter has become popular in recent years as a useful diagnostic tool to detect intracranial pressure variations. Intracranial hypertension is a life-threatening disease with possible poor clinical outcomes and can be caused by a variety of neurological and non-neurological conditions. Considering the latter, increases in intracranial pressure have also been described during several surgical procedures. Ocular ultrasonography might be utilized to identify intracranial pressure increases by evaluating optic nerve sheath diameter variations. The aim of this review is to provide a wide overview on the use of the optic nerve ultrasound evaluation to detect intracranial pressure changes during surgical procedures, also discussing the pitfalls of the B-scan technique, the most widely used for such a purpose. PubMed medical database, Web of Science and Scopus were used to carry out this review. The present review showed that ocular ultrasonography could be considered a valuable diagnostic tool in the surgical setting to indirectly assess intracranial pressure. However, the use of the B-scan ultrasound should always be coupled with the standardized A-scan technique for a more accurate, precise and trustworthy ultrasound assessment.

Optic Nerve Drusen Evaluation: A Comparison between Ultrasound and OCT

This observational study compared optic coherence tomography (OCT) and B-scan in the detection of optic disc drusen. In total, 86 eyes of 50 patients with optic disc drusen (ODD) (36 bilateral) with a mean age of 34.68 ± 23.81 years, and 54 eyes of 27 patients with papilledema, with a mean age of 35.42 years ± 17.47, were examined. Patients with ODD, diagnosed with ultrasound, underwent spectral-domain OCT evaluation. With US, 28 ODD cases were classified as large (4 buried and 24 superficial), 58 were classified as point-like (6 buried, 49 superficial and 3 mixed). Then, all patients underwent OCT. OCT was able to detect the presence of ODD and/or peripapillary hyperreflective ovoid mass structure (PHOMS) in 69 eyes (p < 0.001). In particular, 7 eyes (8.14%) showed the presence of ODD alone, 25 eyes (29.07%) showed only PHOMS and 37 eyes (43.02%) showed ODD and PHOMS. In 17 eyes (19.77%) no ODD or PHOMS were detected. In the papilledema group, no ODD were observed with both US and OCT. OCT showed the presence of drusen or similar lesions in only 80.23% of the cases highlighted by the US scan, so it does not allow for certain ODD diagnoses, especially in the case of buried ODD.

Optic Nerve Ultrasound Evaluation in Idiopathic Intracranial Hypertension

Idiopathic intracranial hypertension (IIH) is a disease with a heterogeneity of possible causes, which needs to be quickly diagnosed. Ocular ultrasonography could be considered a useful tool to diagnose this condition in a fast and non-invasive way. In fact, Karl Ossoinig had already proposed this diagnostic tool in the 1970s for the evaluation of intracranial pressure changes under several pathological conditions, including idiopathic intracranial hypertension. The aim of this review is to analyze scientific articles published in the last 30 years concerning the use of ocular ultrasonography to assess optic nerve indices in patients with idiopathic intracranial hypertension. Specifically, 15 published articles found in PubMed database were included and analyzed in the present review. Our conclusion suggests that ocular ultrasonography is a reliable diagnostic technique to be utilized in all the cases of suspected raised intracranial pressure. To obtain the best possible accuracy and precision in the least invasive way, standardized A-scan seems to be the best choice.

Comparing ultrasonographic optic nerve sheath diameter to head computed tomography scan to predict intracranial pressure elevation

Introduction:

Intracranial hypertension is an emergency condition that needs to be recognized as soon as possible. Lumbar puncture, the gold standard diagnostic procedure for intracranial hypertension, is contraindicated in some conditions while brain imaging procedures may be too difficult to be performed on critically ill patients. To solve this problem, this study aims to assess an alternative method to detect intracranial hypertension by measuring optic nerve sheath diameter using ocular ultrasound and optic nerve sheath diameter difference in each etiology.

Methods:

This cross-sectional study was conducted at the Emergency Department of Dr Iskak Tulungagung General Hospital. Sixty-nine patients who visited the emergency room for the first onset of intracranial pathology were included for optic nerve sheath diameter measurement by ultrasound. Subjects were divided into elevated and non-elevated intracranial pressure groups based on head computed tomography scan findings. The optic nerve sheath diameter results were compared and analyzed.

Result:

There were 29 subjects in the elevated intracranial pressure group and 40 subjects in the non-elevated intracranial pressure group. The mean of optic nerve sheath diameter in the elevated and non-elevated intracranial pressure groups was 0.63 ± 0.06 and 0.57 ± 0.06 cm, respectively (p = 0.000). Based on receiver operating characteristics analysis, 0.58 cm was the most optimal cut-off value.

Conclusion:

Ultrasonographic optic nerve sheath diameter can be used to predict elevated intracranial pressure in suspected patients who are contraindicated to invasive intracranial pressure measurement or critically ill. There were significant differences between elevated and non-elevated intracranial pressure groups in stroke and trauma subjects.

Optic Nerve Ultrasound Evaluation in Animals and Normal Subjects

In recent years, ultrasonographic measurement of the optic nerve sheath diameter (ONSD) has been widely used to identify the presence of increased intracranial pressure (ICP). Intracranial hypertension is a life-threatening condition that can be caused by various neurological and non-neurological disorders, and it is associated to poor clinical results. Ultrasonography could be used to qualitatively and efficiently detect ICP increases, but to reach this purpose, clear cut-off values are mandatory. The aim of this review is to provide a wide overview of the most important scientific publications on optic nerve ultrasound normal values assessment published in the last 30 years. A total of 42 articles selected from PubMed medical database was included in this review. Our analysis showed that ocular ultrasonography is considered to be a valuable diagnostic tool, especially when intracranial hypertension is suspected, but unfortunately this research provided conflicting results that could be due to the different ultrasound protocols. This is mainly caused by the use of B scan alone, which presents several limitations. The use of B-scan coupled with the standardized A-scan approach could give more accurate, and reliable ultrasound evaluation, assuring higher data objectivity.

Diagnostic value of ONSD in sepsis associated encephalopathy of New Zealand rabbits

OBJECTIVE

The purpose of the present study was to assess whether optic nerve sheath diameter (ONSD) measured by ultrasound could predict brain injury in sepsis associated encephalopathy (SAE).

METHODS

A total of 48 male New Zealand White rabbits were used to establish sepsis model. The levels of neuro-specific enolase (NSE), S100B, myeloperoxidase (MPO), and tumor necrosis factor-α (TNF-α) were detected by enzyme-linked immuno sorbent assay and ONSD were measured before modeling, 6 h, 12 h and 24 h after modeling. Sixteen rabbits were sacrificed for hematoxylin-eosin (HE) staining of brain tissue and the brain water content at above time points. Rabbits demonstrated brain injury by HE staining were included in the SAE group, the others were enrolled in the control group. The correlation between ONSD and MPO, NSE and S100B in the SAE group were analyzed. Receiver operator characteristic curves were generated to analyze the area under the curve (AUC), specificity and sensitivity of ONSD values for SAE.

RESULTS

Twenty-nine of 48 rabbits had brain injury, while 19 cases were enrolled in the control group. The level of MPO, NSE, S100B, TNF-α at 6 h, 12 h and 24 h in SAE group were all higher than those of the control group with statistical significance. The ONSD in SAE group increased with time and significantly wider than those in the control group. Correlation analysis revealed that ONSD was positively correlated with MPO, NSE and S100B in the SAE group. The AUCs for the ONSD value in diagnosing SAE at 6 h, 12 h and 24 h were 0.864, 0.957, 0.877, respectively.

CONCLUSIONS

Alterations in ONSD strongly correlated with MPO, NSE and S100B among SAE rabbits. Monitoring of ONSD exhibited a high predictive value for SAE.

The Effect of Biomarkers and Optic Nerve Sheath Diameter in Determining Mortality in non-Traumatic Subarachnoid Hemorrhage

AIM

Although radiological methods are sufficient for the diagnosis of spontaneous subarachnoid hemorrhage (SAH), additional biomarkers are needed to predict prognosis. The aim of this study was to investigate the effects of serum S100B protein, Glial Fibrillary Acidic Protein (GFAP) levels and, Optic Nerve Sheath Diameter (ONSD) on mortality and clinical severity in patients with spontaneous SAH.

MATERIALS AND METHODS

Fifty-six patients who were diagnosed with SAH after first evaluation in the emergency department (ED) were included in the study group; Forty-six patients who were admitted to the ED with headache of non-intracranial etiology, were included as the control group. Cerebral computed tomography (CT) images and peripheral blood samples were obtained from all patients; at the time of diagnosis and 24 h after diagnosis. Serum S100B protein and GFAP levels were measured from the blood samples and ONSD was measured on CT.

RESULTS

Serum S100B protein and GFAP levels and, ONSDs at the time of diagnosis and 24 h after diagnosis were significantly higher in the study group (p < 0.05). Both GFAP levels and ONSD at the time of diagnosis and 24 h after the diagnosis were found to be related with increased mortality (p < 0.05). A similar association was found for serum S100B protein levels 24 h after the diagnosis, but not at the time of diagnosis (p = 0.540).

CONCLUSION

Serum S100B protein and GFAP levels and, ONSD were increased in patients with spontaneous SAH. All parameters were found to be associated with increased mortality.