Mediastinitis following median sternotomy: CT findings.

PURPOSE: To evaluate the usefulness of computed tomography (CT) in the diagnosis of mediastinitis following median sternotomy.

MATERIALS AND METHODS: Fifty patients aged 6 weeks to 80 years (31 male, 19 female) who underwent CT for clinically suspected mediastinitis following median sternotomy were retrospectively identified. CT scans were evaluated for primary findings (localized mediastinal fluid, pneumomediastinum, or both) versus secondary or other findings (mediastinal edema, adenopathy, pleural effusion, or a sternal or lung abnormality). Patients were divided into three groups on the basis of the CT findings and final clinical diagnosis: those with primary CT signs and a final diagnosis of mediastinitis, those with primary CT signs of mediastinitis and a different final diagnosis, and those with neither primary CT findings nor a final diagnosis of mediastinitis.

RESULTS: All patients with clinical mediastinitis had primary CT findings. These patients under went CT an average of 24 days after surgery. Patients with primary CT findings and a final clinical diagnosis of something other than mediastinitis underwent CT an average of 9 days following following surgery. Through postoperative day 14, CT had a sensitivity of 100% for clinical mediastinitis but a specificity of 33%; after postoperative day 14, the sensitivity was 100% and the specificity was 100%.

CONCLUSION: Primary CT findings are not specific for mediastinitis through postoperative day 14; after day 14, they are highly indicative of mediastinitis.