SIMON FRASER / SCIENCE PHOTO LIBRARY SIMON FRASER / SCIENCE PHOTO LIBRARY
Inflamed lymph node. Colour Doppler ultrasound scan of increased blood flow (red and blue) in an inflamed lymph node in the neck of a 40-year-old woman. The colour-coding shows the direction of the blood flow, away (blue) or towards (red) the detector. It can also distinguish between fast (bright) and slow (dark) flow. Inflammation of a lymph node (lymphadenitis) is usually a response to an infection. The increased lymph node activity produces more of the immune system's lymphocyte cells that fight infection. Colour Doppler ultrasound scanning colour-codes moving fluids, like blood, by detecting the frequency change they cause when reflecting high-frequency sound waves.
Model release not required. Property release not required.