A novel SA technique not only improves the accuracy of ultrasound in assessing hydrocephalus, by analysing the dynamic properties of the back of the eye as a marker of pressure in the brain, but simplifies the process so it can be performed at a very basic healthcare level.
At a Café Scientifique meeting hosted by the research contracts and innovation department at the University of Cape Town and supported by intellectual property law firm Spoor & Fisher, paediatric neurosurgeon Dr Llewellyn Padayachy described a novel diagnostic method which uses the eye as a window to the brain.
Previously, the diagnosis of hydrocephalus and other causes of raised pressure in the brain involved drilling a hole in the skull in order to measure this pressure. This invasive and expensive method however, comes with the risk of infection and bleeding. Assessing pressure inside the brain is a vital part of diagnosing certain neurosurgical conditions including brain tumours, cranial deformities, traumatic brain injury and infection.
The eye with its natural connection to the brain delivers essential visual information but can also be used to extract information from the brain, the audience heard.
Motivated by the case of a particularly special child, which Padayachy says, "would've made him happier if diagnosed earlier," the team started pushing the boundaries of what traditional ultrasound imaging technology could achieve.
"Once you understand the relationship between the eye and the brain, you can then find ways "see" what you want. It's not science fiction, the idea of using the eye as the window to the soul can in fact be traced all the way back to the biblical era, with some references even predating the Bible," adds Padayachy.
While accurate data regarding the number of hydrocephalus cases on the African continent is sparse, conservative estimates put it at some 100,000 cases annually. In the US, it affects approximately 1m people in every stage of life, from infants to the elderly and is said to be as common as Down's syndrome and more common than spina bifida or brain tumours (Hydrocephalus Association).
"Sadly, it is also the most common indication for brain surgery in children. Over the past few decades, there have been limited significant advances in the treatment of hydrocephalus, hence it is imperative that these cases are detected early," says Padayachy.
The scientific team from Norway and South Africa working on this development realised the potential of traditional static ultrasound assessment of the eye as a non-invasive method for detecting raised pressure in the brain, but also identified the shortcomings in its diagnostic accuracy. They knew that advancing the current static imaging method was going to be the magic bullet.
Their novel technique not only improves accuracy by analysing the dynamic properties of the back of the eye as a marker of pressure in the brain, but perhaps more importantly simplifies the acquisition process so it can be performed at a very basic healthcare level.
According to Padayachy, the eye is directly linked to the brain by the optic nerve which sits at the back of the eyeball. The optic nerve sheath is a balloon-shaped structure. As pressure in the brain builds up, fluid from the brain is forced along this sheath. It dilates this sheath in the same way that a balloon is inflated.
"We figured that if this sheath appeared 'stretched' when we compared it to other clinical and imaging markers, then this information could be really useful."
This article was first published in the Medical Brief.
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