11
Table 3. Radiological Terms for Heterogenous Lung
Attenuation
Terminology Significance Description
"ree-density
pattern"
a
• Term coined to replace the
"headcheese" sign, since most
individuals worldwide do not
relate to the headcheese sign
• Combination of three
attenuations on inspiratory
CT images:
a. Normal-appearing lung
b. High attenuation (GGO)
c. Lucent lung (i.e., regions
of decreased attenuation
and decreased vascular
sections)
• Indicative of a mixed obstructive
and infiltrative process:
a. The obstructive abnormality
(seen in small airway disease)
is manifested by areas of
decreased attenuation and
decreased vascularity.
b. The infiltrative disorder results
in GGO surrounding preserved
normal lobules.
• Sharply demarcated from
each other
• Highly specific for fibrotic HP;
has not been shown to be specific
for nonfibrotic HP
a
e term "three-density pattern" was coined by this committee. is descriptive pattern was
unanimously determined by the committee to be the preferred term. is pattern has been shown
to differentiate fibrotic HP from idiopathic pulmonary fibrosis and, thus, raises the index of
suspicion for the diagnosis of fibrotic HP whenever present. However, it is unknown whether the
pattern is also present in nonfibrotic HP. Some radiologists relate this pattern to the appearance
of headcheese and, therefore, it has been referred to as the "headcheese sign" in the literature. e
guideline committee strongly discourages the use of the term "headcheese" to describe this pattern.
(cont'd)
