Correct!
3. Thoracic CT
Thoracic MRI can be employed for the investigation of mediastinal lesions, thoracic lymphadenopathy, chest wall lesions, and pleural abnormalities, but is less efficacious for the assessment of pulmonary abnormalities, particularly diffuse lung diseases; typically, thoracic CT is preferred for this application. Thoracic applications for 18FDG-PET scanning commonly include assessment of the solitary, indeterminate lung nodule and staging for pulmonary and extrathoracic malignancies; diffuse lung diseases are not typically evaluated with this modality. Some causes of alveolitis can produce elevated pulmonary parenchymal tracer uptake, as can pulmonary nodules in patients with sarcoidosis, but often these findings are incidentally detected at 18FDG-PET rather than intentionally evaluated with this technique. Ventilation-perfusion scintigraphy is commonly employed for the investigation of suspected pulmonary embolism, and less commonly to determine split lung function prior to pulmonary resections or to evaluate patients with pulmonary hypertension. In this circumstance, it would be reasonable to obtain ventilation-perfusion scintigraphy to assess for acute pulmonary embolism as a cause of the patient’s complaints of chest pain and shortness of breath; however, ventilation-perfusion scintigraphy would not be useful for the evaluation of this patient’s chest radiographic abnormalities. Transthoracic needle biopsy, either fluoroscopically or CT-guided, is primarily employed for establishing a diagnosis for focal pulmonary abnormalities, not diffuse lung disorders. Thoracic CT is the single best non-invasive test for characterizing the chest radiographic abnormalities).
Clinical course: The patient subsequently underwent unenhanced thoracic CT (Figure 2).
Figure 2: Axial unenhanced thoracic CT displayed in lung windows.
Which of the following statements regarding this imaging study is most accurate? (Click on the correct answer to proceed to the next panel)