Ultrasound Gain Settings: Adjusting Adjusting Ultrasound Image Brightness
©Walter Rasmussen, R.D.C.S.
How should an ultrasound image look? The student of Sonography should observe a lot of images in textbooks, ultrasound publications and quality websites to learn what the standard for good imaging looks like. A good image demonstrates structure with good resolution and even illumination throughout the image. This involves using all of the adjustments covered in this guide pertaining to two-dimensional image control.
The Gain control adjusts the overall amplification of the returning reflections displayed on the ultrasound image. The gain adjustment can be likened to the brightness adjustment on a television. The Gain control works hand-in-hand with the Dynamic Range, Compression and Reject controls. Typically, the brighter the image is made with the adjustment of Gain, the more Dynamic Range and Compression will need to be decreased to keep from obscuring desired details. With increases in Gain, Reject will need to increased in order to suppress noise.
Below: Serial echocardiograms for Gain technique comparison. Two sonographers with different gain settings for the same patient.
Upper: Gain adjusted for good structure visualization. Lower: Gain adjusted too high, obliterating detail.
Gain Increase–Decrease Dynamic Range and/or Compression or Increase Reject to suppress weaker echoes.
Gain Decrease– Increase Dynamic Range and/or Compression or decrease Reject to enhance weak echoes.
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