Fig. 3

Bedside CXR and simulated DTS reconstruction of a 49-year-old man who was admitted to the ICU after a neurosurgical intervention with removal of a fourth ventricle ependymoma. Five days after surgery he developed respiratory insufficiency. a Bedside CXR shows subcutaneous emphysema in the neck and pulmonary consolidations bilaterally in the basal parts of both lungs. b Simulated DTS acquisition from a CT examination, performed 1 h later. Because of the discrepancy between respiratory function and findings on CXR, the CT examination was performed to rule out pulmonary embolism. c Slice of the DTS reconstruction of the simulated acquisitions at the level of the heart shows linear areas of hyperlucency around the heart and in the paravertebral region (black arrows). Also note an area of relative hyperlucency in the left lung with a clear delineation of the adjacent consolidation (white arrows). These findings are consistent with pneumomediastinum. d Slice of the DTS reconstruction of the simulated acquisitions more posterior than DTS reconstruction A shown in c, showing a large retrocardiac consolidation with air bronchogram (black arrows). e A coronal reformatted CT image confirms the pneumomediastinum and a large consolidation (f) with air bronchogram, consistent with subtotal atelectasis of the left lower lobe. Due to the retrocardiac location, the consolidation is not visible on the CXR. Moreover, the extent of the pneumomediastinum is better appreciated on the DTS reconstructions compared to the bedside radiograph