Figure 4. A 42-year-old man with acute myelogenous leukaemia (AML) and fever in neutropenia, following chemotherapy. (a) Chest CT revealed a solitary pulmonary nodule (white arrow) in the right upper lung lobe. (b) 3 months later, MRI (axial post-contrast T₁ weighted spin echo (SE) scan) of the paranasal sinus region showed circular swelling of the mucosa of the left maxillary sinus with relatively low intensity on T₂ weighted scans confined to small areas of the medial sinus wall (white arrow). (c) At follow up MRI (axial post-contrast T₁ weighted SE scan) progression of local infection with involvement of the left orbit was diagnosed (white arrow). Note areas of non-enhancing tissue due to infarction. (d) Despite intensive antifungal therapy, contiguous bone permeation with extension of the fungal process to the frontal dura and frontal lobe (white arrow) was disclosed on axial post-contrast T₁ weighted scan.