Imaging findings in the pulmonary aspergilloses can answer important clinical questions. Steroid-responsive chronic asthma due to allergic bronchopulmonary aspergillosis can be differentiated from simple asthma by computed tomography (CT) evidence of extensive and severe central bronchiectasis, mucoid impaction, or small airways lesions. The simple aspergilloma can be differentiated from the complex aspergilloma by the absence of: constitutional symptoms, para-cystic lung opacities, cyst expansion, or progressive pleural thickening. The CT halo sign is a transient finding that can provide a probable diagnosis of early invasive pulmonary aspergillosis in patients who are at extraordinarily high risk of the infection. Patients with a halo sign at baseline are more likely to have a satisfactory treatment response than those without this indicator.