A new novel method for assessing intracranial pressure using non-invasive fundus images: a pilot study

Mikkel Schou Andersen,Christian Bonde Pedersen,Frantz Rom Poulsen

doi:10.1038/s41598-020-70084-0

Mikkel Schou Andersen, Christian Bonde Pedersen + Show 1 more

Open Access

https://doi.org/10.1038/s41598-020-70084-0

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Abstract

Arteriole and venule diameter ratio (A/V-ratio) can be measured using fundus photography. In this pilot study, we correlated changes in the intracranial pressure with the diameter of vessels of the retina. We investigated whether increased intracranial pressure (ICP) was reflected in a measurable and quantifiable distention of the venule diameter, leading to a decreased A/V-ratio. This was demonstrated by assessment of the A/V-ratio in patients already undergoing conventional ICP monitoring with a cerebral intraparenchymal pressure monitor. Our method shows a correlation between A/V ratio and ICP and suggests an easily obtainable and usable point-of-care (POC), non-invasive method to estimate the intracranial pressure without the necessity of mydriatic drugs. Furthermore, the sensitivity/specificity analysis with a cut-off of < 0.8015 A/V-ratio, showed a sensitivity of 94% [85–98%] and a specificity of 50% [34–66%] with a positive likelihood ratio of 9.0. This means that in a clinical setting there is a 94% chance of correctly identifying individuals with ICP ≥ 20 mmHg.

Highlights

Arteriole and venule diameter ratio (A/V-ratio) can be measured using fundus photography
intracranial pressure (ICP) monitoring is considered paramount in diseases like intracranial hemorrhages, traumatic brain injury, subarachnoid hemorrhages, malignant infarction, cerebral edema and infections of the central nervous system to optimize treatment of secondary brain injuries and thereby improve o utcome[7]
Of the 24 patients, 20 patients were suspected of normal pressure hydrocephalus (NPH) and four were suspected of ventriculoperitoneal (VP) shunt dysfunction

Summary

Introduction

Arteriole and venule diameter ratio (A/V-ratio) can be measured using fundus photography. We investigated whether increased intracranial pressure (ICP) was reflected in a measurable and quantifiable distention of the venule diameter, leading to a decreased A/V-ratio. This was demonstrated by assessment of the A/V-ratio in patients already undergoing conventional ICP monitoring with a cerebral intraparenchymal pressure monitor. The most promising non-invasive ICP measuring methods studied are pupillometry 14 and optic nerve sheath diameter[15]. They have not been validated for daily clinical use and are prone to a high degree of inter-observer v ariations[16]. A quick, non-invasive and easyto-use screening tool for intracranial pressure would be of great benefit in such and other cases, where elevated intracranial pressure can be a potential hazard

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