Ultrasound measurement of optic nerve sheath diameter in monitoring increased intracranial pressure

This article was professionally consulted by Specialist Doctor II Khong Tien Dat - Radiologist - Radiology Department - Vinmec Ha Long International Hospital. The doctor has more than 14 years of experience in the field of diagnostic imaging.

Ultrasonic optic nerve sheath diameter measurement is a modern, highly accurate technique applied in monitoring increased intracranial pressure. Currently, optic nerve ultrasound is widely used because of its simple operation and ease of operation in medical facilities.

Methods for monitoring raised intracranial pressure include invasive and non-invasive methods. In particular, the invasive method is conducted with a rate of about 50% on patients indicated for follow-up due to concerns about possible complications such as bleeding, infection, or lack of accuracy and cost. high. In contrast, the non-invasive method is easy to implement and therefore widely applied.
Continuous monitoring of raised intracranial pressure improves mortality in patients with severe traumatic brain injury.
Invasive methods include:
Ventricular drainage Catheter brain parenchyma Measure with pressure sensing balloon Non-invasive method:
Transcranial doppler ultrasound Ultrasound measure the diameter of the optic nerve sheath.

Ultrasound technique to measure the diameter of the optic nerve sheath is performed as follows:
Step 1: The patient lies supine on the bed. Step 2: The sonographer uses a flat transducer, f: 7-12MHz, B-mode. Step 3: Place the probe in the upper outer part of the eye socket. Step 4: Measure at 3mm behind the eyeball.

Studies have been performed and shown that there is a strong correlation between increased intracranial pressure and optic nerve sheath diameter measurements, as optic nerve capsule diameter increases, suggesting the diagnosis. increased intracranial pressure.
In addition, a number of studies have also been conducted to find out the threshold value of the optic nerve sheath diameter:
When the intracranial pressure is > 20mmHg: the value of the optic nerve sheath diameter is 5.4 ± 0.49mm. When intracranial pressure is < 20 mmHg: optic nerve sheath diameter is 4.4 ± 0.49mm. With the measured optic nerve sheath diameter > 5 mm used in the diagnosis of ICP when ICP > 20 mmHg, there will be a sensitivity of 88% and a specificity of 93%.

Ultrasonic optic nerve sheath diameter measurement in monitoring raised intracranial pressure is a noninvasive technique that can be used in the following cases:
Invasive techniques cannot be performed. Suspected increased intracranial pressure. Exclude increased intracranial pressure in clinical examination in patients with vomiting, nausea but no signs of ventricular dilatation or coma. Ultrasound measuring the diameter of the optic nerve sheath has the following advantages:
Easy to perform by experienced sonographers Less complications and risks for the patient. However, the disadvantage of this method is that the evaluation is interrupted and the execution is not continuous.
Ultrasound measuring the diameter of the optic nerve sheath in monitoring increased intracranial pressure is a safe and simple procedure, giving results with high accuracy, contributing to improving the effectiveness of hypertension treatment. intracranially and improve prognosis.
Vinmec International General Hospital has applied ultrasound technology in examination and diagnosis of many diseases, in which ultrasound method. The ultrasound technique to measure the diameter of the optic nerve sheath in monitoring increased intracranial pressure at Vinmec is performed methodically and in accordance with standard procedures by a team of highly qualified medical professionals and modern machinery. This results in accurate results, greatly contributing to the identification of the disease and the stage of the disease to coordinate with other specialties to come up with the most effective treatment regimen.