The management of infections in haematology is dictated by the patient’s type of acquired or induced immune deficiency (neutropenia, deficiency in cell-mediated or antibody-mediated immunity), and findings from clinical examination, laboratory studies, or morphologic investigations. The CT scan dominates in the initial management and follow-up of these patients, since clinical features very often appear to be non-specific. The radiologist’s role is to guide the clinician towards a specific diagnosis such as aspergillosis or pneumocystosis, or to point them towards a non-infectious cause: tumour localisation, hypervolaemia, bronchiolitis obliterans suggestive of GVH disease, drug toxicity, or embolism.