Centrilobular nodules – “tree-in-bud” sign

Centrilobular nodules can be accompanied by structures called "tree-in-bud" opacities, which resemble a budding tree. Showing a branching structure, it represents an impacted centrilobular bronchus dilated by pus, mucus or fluid. This occurrence is almost always associated with inflammation due to pulmonary infections. The identification of Y- and V-shaped structures on HRCT images is of value for narrowing the differential diagnosis.7,9

Centrilobular nodules – “tree-in-bud” signCentrilobular nodules – “tree-in-bud” sign