[X-ray computed tomography in the course of mediastinitis after sternostomy for heart surgery]

Results are reported of a prospective study of 79 CT scan examinations in 50 patients who had undergone sternotomy for cardiovascular surgery. In 69 cases the examination was conducted during the course of a progressive postoperative mediastinitis treated surgically. Mediastinitis was confirmed in 13 cases, including 12 relapses. In 2 cases the CT scan image was normal (2 false negatives) whereas mediastinal drains had been inserted. The CT scan image of mediastinitis shows mainly hypodense fluid collections (0 to 16 UH) in anterior mediastinum or between sternotomy borders (8 of 13 cases). But this type of image, detected 11 times in the absence of recurrence (favorable course), can result from a residual serous collection after ablation of drains. In 8 cases, a CT scan-guided puncture (7 cases) or one under ultrasound control (1 case) eliminated recurrence. The CT scan imaging also allowed diagnosis of 5 cases of osteitis, confirmed surgically. These findings indicate the definite interest of CT scan imaging in postoperative follow-up review of median sternotomies. It appears to be particularly indispensable for surveillance of surgically treated mediastinitis, because of the serious consequences of relapses and the often clinically silent chronic bone lesion. However, the possibility of residual serous collections emphasizes the importance of the clinical context and should lead to guided puncture investigation in doubtful cases.