Abdominal x rays made easy: calcification

As outlined earlier in the series a small number of densities may be seen on plain radiographs. The most radio-opaque (brightest) of any natural substance is calcium, which appears white. The reason calcium shows the greatest radio-opacity is that it “obstructs” x rays more than any other natural substance. Consequently, fewer of those x rays reach the x ray plate, and the film appears white.

Iatrogenic or artefactual metallic objects appear even brighter white (this will be discussed in the final part of this series). The vast majority of calcium is contained in the bones--a normal, expected location (bony abnormalities will be covered in the next part of this series).

The incidence of physiological calcification of normal anatomical structures increases with age and reflects that calcium is deposited over time.

Calcium can be seen in normal and abnormal structures. Abnormal calcification in some cases merely indicates underlying pathology whereas in others the calcification is the pathology.