Hematogenous osteomyelitis with fat-fluid level shown by CT.

Computed tomography (CT) revealed fat-fluid (pus) levels in two adult patients who had hematogenous osteomyelitis due to gram-negative organisms: in one patient within an intraosseous cavity, and in another patient within the adjacent suprapatellar bursae. Both patients were hospitalized for other chronic illnesses and had confusing clinical manifestations with non-specific radiographic changes. Observation of fluid levels, in addition to bony erosions, correctly suggested the presence of pus, and in one patient prompted a diagnostic intraosseous aspiration. To our knowledge, this CT sign of hematogenous osteomyelitis has not been previously reported.