Radiologic approach to the diagnosis of infectious pulmonary diseases in patients infected with the human immunodeficiency virus

Nearly all patients infected with HIV experience respiratory infection at some point in the course of their illness. The spectrum of infections is varied and in order to generate a useful differential diagnosis based on imaging findings it is imperative for the radiologist to be aware of changing trends in disease prevalence and epidemiology, and the possible pathology related to new therapies. The characterization of the radiographic pattern in correlation with clinical findings and laboratory values (in particular the degree of immunosuppression as reflected in the CD4 level) would be helpful in narrowing the differential diagnosis of infectious pulmonary disease in HIV-positive patients. The most common radiologic patterns considered include areas of ground-glass, consolidation, nodules, and lymphadenopathy. We also include airways diseases and cavitary/cystic lesions because their prevalence has increased over recent years, and we also mention the significance of a normal chest radiograph in the suspicion of a lung infection. In most cases, the clinical and radiographic findings are sufficient for confident diagnosis. The radiologic diagnosis of thoracic infections in patients with AIDS has improved with the use of CT. The greatest value of CT is in excluding lung disease when the radiographic findings are equivocal and in confirming the presence of clinically suspected disease when the radiograph is normal.