Headcheese sign.

Appearance: The headcheese sign on chest CT is characterized by the juxtaposition of lobular regions of low, normal, and high attenuation.1 This results in 3 (or more) different densities on CT that are sharply demarcated from each other. The abrupt density transitions reflect the margins of secondary pulmonary lobules. Low attenuation lobules almost always reflect air trapping, which can be confirmed on end-expiratory CT.2 The CT imaging pattern is reminiscent of the variegated appearance of headcheese cold cut meat.