Scanning technology enables faster medical diagnosis

Portable medical scanning technology on a par with MRI and CT could soon find its way into GP surgeries, aiding the quicker diagnosis of various conditions.

The system can be retrofitted to existing ultrasound platforms, but has the added ability to differentiate between tissue types, opening up areas such as cancer diagnosis.

In terms of spatial resolution, magnetic resonance imaging (MRI) and computed tomography (CT) are the current gold standard, but are time consuming and require the use of large, expensive magnets and the injection of a contrast agent.

Ultrasound technology is more amenable, but despite recent advances cannot resolve with sufficient detail for all but the most basic applications.

A team from Oxford University’s Department of Engineering Science experimented with combinations of electromagnetic and acoustic waves to refine its technology — now being patented as Oxford Electromagnetic Acoustic Imaging (OxEMA).

‘It’s a real-time imaging system so you put a gel on patients as you do in ultrasound but you don’t have to put them through a hole as with MRI, and it’s a portable device so every GP can have it next to them,’ said Dr Rakesh Roshan of Isis Innovation, Oxford’s technology transfer unit.

Crucially, the technology can discriminate between the different mechanical and electrical properties of tissues, allowing the identification of various anomalies.

In a recent trial of the technology, a calcium carbonate stone was introduced in a sheep’s kidney, which was then scanned with ultrasound and subsequently with the OxEMA upgrade. While ultrasound failed to resolve the kidney stone, it clearly showed up as a brightly coloured area of relatively high permittivity and conductivity with OxEMA.

The team also claims that OxEMA will allow the earlier diagnosis of tumours, including those of the breast, liver and thyroid, as well as having application in orthopaedics.

‘We are not saying that this product will completely replace MRI systems, but there is a big gap in the market, since every patient cannot be taken through the MRI system straight away because there is a queue in the hospital. Oxford has, I think, only three MRI scanners,’ Roshan said.

A preliminary image of a sheep’s kidney where the OxEMA scan clearly identifies the artificially introduced abnormality (mimicking a stone) which is not clearly differentiated using conventional ultrasound
(i) Section through a sheep’s kidney, into which a calcium carbonate nodule has been inserted as a proxy for a kidney stone or vascularised tumour — location shown by red ring. (ii) The same section, with a registered ultrasound image superposed — the nodule can be seen, but is not differentiated from other features in the kidney. (iii) The same section, with the ultrasound and OxEMA scan superposed. The different electrical properties of the anomaly stand out extremely clearly in the OxEMA scan as a brightly coloured area of relatively high permittivity and conductivity