No abstract available. Article truncated at 150 words. A 60-year-old man in the surgical intensive care unit for atrial fibrillation with rapid ventricular response, on his second post-operative day following colectomy, complained of worsening shortness of breath. A chest radiograph (Figure 1) was obtained. A chest radiograph performed one day previous to Figure 1 showed clear lungs, no pleural effusions, and no volume loss.Question 1 and Figure 1: What are the abnormal findings on the chest radiograph? In particular, what technical error has occurred? The frontal chest radiograph shows increased opacity in the bases bilaterally, greater on the side labeled left (see “L” in the image- this is the technologist’s marker). Note the shift of the trachea towards the side labeled left. However, note also the opacity along the superior mediastinum on the right side; this opacity has the appearance of the aortic arch. Note the appearance of the stomach below the diaphragm, ipsilateral to the aortic