Correct!
3. Contrast-enhanced thoracic CT
Contrast-enhanced thoracic CT is the next most appropriate step among the choices listed. Thoracic ultrasound would be useful for evaluating the pleural fluid but this finding has not changed compared to the prior chest radiograph. Similarly, decubitus chest radiography could demonstrate whether or not the left pleural effusion is loculated versus free-flowing, but the lack of change in the size and configuration of the left pleural effusion at chest radiography suggests that this finding need not be the target of active investigation. 99mTc-Ventilation-perfusion scintigraphy is often useful for the investigation of suspected pulmonary embolism, but is unlikely to provide a diagnostic result (either high or low / very low probability for pulmonary embolism, or normal), in an intubated patient with numerous pulmonary abnormalities. 68Ga-citrate scanning can be useful for the assessment of some diffuse lung disorders but would not be helpful in the setting of new nodular opacities in an acutely ill patient- lack of tracer uptake would not provide and explanation for the new nodular opacities, and active tracer accumulation within these opacities would not provide a specific enough list of differential diagnostic possibilities to allow presumptive therapy or direct intervention.
Repeat thoracic CT using a pulmonary embolism protocol was performed (Figure 5).
Figure 6. Panels A-H: Axial contrast-enhanced thoracic CT displayed in lung (A-E) and soft tissue (F-H) windows. Panels I-0: Caudally acquired axial contrast-enhanced thoracic CT images. Lower Panel: Movie of CT scan in lung windows.
Which of the following statements regarding the enhanced thoracic CT study is most accurate? (Click on the correct answer to proceed to the 6th of 7 panels)