When a solitary pulmonary nodule is seen on computed tomography (CT), which of the following radiological features suggest it is benign?
a) Air bronchograms within the nodule
b) Amorphous calcification within the nodule
c) CT attenuation of -10 Hounsfield units (HU)
d) Lobulated outline of the nodule
e) Enhancement of the nodule by less than 15 HU following intravenous contrast
The correct answer is b) Amorphous calcification within the nodule.
Amorphous calcification, also known as benign or diffuse calcification, is a radiological feature that suggests a solitary pulmonary nodule is benign. This type of calcification is often seen in benign lesions such as hamartomas or granulomas.