RB-ILD in a 44-year-old woman with a 20 pack-year smoking history. HRCT image of the upper lung lobes shows centrilobular nodules (white arrows), patchy ground-glass opacities (black arrow), and mild coexisting centrilobular emphysema (arrowhead). *Mueller-Mang C, Grosse C, Schmid K, et al.: What every radiologist should know about idiopathic interstitial pneumonias. Radiographics 2007, 27:595–615. With permission from The Radiological Society of North America.