Seeing the nerves within us.

Using a new magnetic resonance imaging (MRI) technique, a team of British and American researchers has obtained the clearest images yet of nerves within the body. Lead researcher Aaron G. Filler of the University of Washington in Seattle says that with modifications, commercial MRI scanners may help physicians diagnose and treat nerve-related pain and weakness much more effectively. In ordinary MRI scans and X-ray images, nerves are difficult to distinguish from other tissues, Filler says.

This cross section of a human leg highlights the sciatic nerve (bright area in the center), which channels nerve impulses to the pelvis, legs, and feet. By adjusting the magnetic fields and radio pulses used to probe the body during MRI scans, the researchers can selectively de-emphasize various tissues, leaving the image of the nerves shining out "like the smile of the Cheshire cat in Alice in Wonderland," Filler explains.

MRI scanners can combine these cross sections into three-dimensional images of the body's nerve networks. This technique may eventually help surgeons locate and repair the damaged or squeezed nerves that cause lower-back pain, for example. The researchers describe the new technique in the March 13 Lancet.