Allergic bronchopulmonary and sinus aspergillosis: the roentgenologic spectrum.

Allergic bronchopulmonary aspergillosis (ABPA) and allergic Aspergillus sinusitis (AAS) are the best recognized manifestations of Aspergillus-associated hypersensitivity respiratory disorders. These conditions occur predominantly in atopic individuals. Roentgenologic techniques play a pivotal role in the diagnosis of these two conditions. ABPA, on imaging, is characterized by fleeting pulmonary infiltrates often confused with pulmonary tuberculosis. However, central bronchiectasis on computed tomography (CT) is considered to be the hallmark of the disease. Though the diagnosis of AAS is primarily based on histopathology, roentgenology is essential for the diagnosis. Haziness of one or more paranasal sinuses is almost always seen on plain roentgenograms. However, CT proffers more reliable information with characteristic features that include heterogeneous densities and serpiginous areas of increased attenuation on non-contrast scans. Early diagnosis, with the help of roentgenologic techniques, and appropriate therapy could alter the natural history of these diseases.