CT of the lung: patterns of calcification and other high-attenuation abnormalities.

CT is the most sensitive radiologic method for the detection of differences in radiographic density in chest lesions. Areas of high attenuation (visually as opaque as bony structures) in an abnormality on CT scans can be an important clue to the correct diagnosis. The high attenuation is most often caused by calcification, but may also be due to iodine, barium, or radiopaque foreign bodies. This essay illustrates the patterns of high attenuation associated with chest diseases on unenhanced CT scans.