Allergic bronchopulmonary aspergillosis: Lessons for the busy radiologist

The probability of a radiologist interpreting a disease correctly is not only influenced by their training and experience but also on the knowledge of a particular entity. This editorial reviews certain myths and realities associated with radiological manifestations of allergic bronchopulmonary aspergillosis (ABPA). ABPA is a hypersensitivity disorder against the antigens of Aspergillus fumigatus. Although commonly manifesting with central bronchiectasis (CB), the disorder can present without any abnormalities on high-resolution computed tomography (HRCT) of the chest, so-called serologic ABPA (ABPA-S). HRCT of the chest should not be used in screening or in the initial diagnostic work up of asthmatics, as asthma without ABPA can manifest with findings of CB. High-attenuation mucus (HAM) is the pathognomonic sign of ABPA and is very helpful in the diagnosis of ABPA complicating asthma and cystic fibrosis. Instead of classifying ABPA based on the presence and absence of CB into ABPA-CB and ABPA-S respectively, ABPA should be classified as ABPA-S, ABPA-CB and ABPA-CB-HAM. The classification scheme based on HAM not only identifies an immunologically severe disease but also predicts a patient with increased risk of recurrent relapses.