Bubble, bubble...spot the trouble

A cancer screening technique that uses ultrasound to track the movement of tiny gas bubbles around a patient’s blood system is claimed to be quicker and more accurate than existing diagnostic methods.

Developed by engineers at Siemens Medical Solutions in Germany, the technique is being used at a number of European hospitals for the diagnosis of liver cancer. It is also being evaluated for potential use in cardiology and breast cancer screening.

The technique works by injecting microscopic gas bubbles into a vein. These remain in the patient’s circulation for approximately 15 minutes before being harmlessly exhaled.

As they travel around the body, bubbles concentrate in characteristic patterns around potentially cancerous areas. The concentration is then monitored using a specially developed ultrasound technique known as Cadence Contrast Pulse Sequencing Technology (CPS).

This operates by transmitting specific sound sequences designed to make the gas bubbles oscillate. Processing is then used to separate the oscillation of the bubbles from that of the surrounding body.

According to Siemens, not only does CPS enable surgeons to detect the concentration of bubbles safely and quickly, but the technique is also more accurate than existing ultrasound methods.

The company claimed its use enables more effective detection of smaller tumours or metastases (secondary tumours) than previous ultrasound methods.

‘Using CPS technology we can accurately display the smallest tumour vessels even with low quantities of contrast medium,’ said assistant professor Dr Deike Strobel, head of the ultrasound department at the University Hospital in Erlangen.

German doctors said the technology was particularly promising as a faster method for diagnosing liver tumours, reducing the need for more complex or expensive imaging methods and making it possible to differentiate between malignant and benign growths.