Presentation
Fever, frontal headaches, sense of nasal congestion.
Patient Data

Four gas-fluid levels are depicted, indicating acute sinusitis. There is also mucosal thickening on both the maxillary sinuses, suggestive of coexisting chronic sinusitis. The sphenoid sinuses appear normal.

Gas-fluid levels (red arrows), indicating acute sinusitis. Mucosal thickening of the maxillary sinuses (blue arrows), suggestive of chronic sinusitis.
Case Discussion
The diagnosis was based upon the clinical and characteristic imaging findings of acute sinusitis, on the ground of coexistent chronic sinusitis (of the maxillary sinuses). Although a gas-fluid level is a common finding in such cases, the presence of four gas-fluid levels simultaneously is somewhat unexpected.
Image courtesy of Dr Nikolaos Pantazis, MD Radiology (GRE).