Fibre-optic coils monitor lungs and heart

17 Jun 2002

Researchers at Kingston University in London have developed a device that allows technicians to see immediately magnetic resonance imaging (MRI) pictures of the inside of the body without patients having to hold their breath for long periods.

Instead of having to wait until the scan is over to check the quality of the measurements, technicians can see the results immediately. The researchers also realized that, as well as detecting breathing, the system was picking up a faint heartbeat. They have now produced a version of the device that is capable of measuring both the respiration and the heart rate of a patient. Images of the heart captured by the scanner can be matched, frame by frame, to the signal recorded from the heartbeat. Successive images of the heart at a particular point in its cycle can then be picked out and superimposed on each other to produce a clearer picture.

The device consists of coils of optical fibre attached to the patient's chest and abdomen. When optical fibres are bent into a curve, part of any light travelling down them is lost out of the side. The tighter the bend, the more light is lost.

In the new system, breathing movement makes the coils in the optical fibre tighter or looser, which affects the amount of light coming out of the end of the fibre. A pounding heart also alters the shape of the coils, but to a lesser degree.

The researchers plan to test the system inside an MRI scanner in the next few months.