Question

how does contrast affect the diagnostic quality of radiographs?
what setting would directly affect contrast?
what is the difference between high and low contrast?
when would we want radiographs with low contrast?
when would we want radiographs with high contrast?

Answer 1

Radiography is a very useful technique in medical diagnosis of a medical condition. It is an imaging technique in which X-rays, gamma rays or any ionization radiation and even non-ionization radiations are used to view the internal form of the organs. It helps to detect any abnormality as the image of the organ comes on a plate.

* Radiographic contrast contrast is the density difference between neighboring regions of a tissue being radiographed. Any abnormality appears on the radiograph. High radigraphic contrast is observed in radiographs where density differences are more. It helps the radiologist to make a better and more accurate diagnosis.

* Scale setting or Contrast Resolution directly affects contrast.

Exposing a film to produce higher film densities will generally increase the contrast in a radiograph.

* As the name suggests, in high radiographic contrast density differences are notably distinguished as black and white on the radiograph. In low radiographic contrast images the density differences among tissues appear in lower contrast such as black to grey in color, on the radiograph.

* Long scale radiograph are considered 'lower contrast' because in this density differences are less noticeable. However, low density contrasts possess many more shades of grey. Lung field examinations generally require low density contrast examinations because even slight changes in the tissues appear in the diagnostic image.

* High density contrasts are needed when taking a radiograph of the brain to detect a tumor or hemorrhage or while examining the alimentary canal. This is done so that a clear and contrasting image of the tissues appears on the radiograph.