Correct!
5. None of the above
Certainly choice 1- chronic obstructive pulmonary disease due to cigarette smoking- is contributing to the patient’s shortness of breath by accounting for the appearance of the centrilobular emphysema seen in the apices on the patient’s thoracic CT. However, cigarette smoking-induced emphysema may not entirely account for the diffuse lobular low attenuation in the bases. The thoracic CT shows no evidence of bronchiectasis or cystic lung disease, so these choices are not correct. Bronchiolitis obliterans often appears as an area of segmental airway thickening and dilation with focal low attenuation in the lung parenchyma subtended by the abnormal bronchi, also accompanied by a small ipsilateral pulmonary artery (this is often the appearance of Swyer-James syndrome)- this morphology is not present on the thoracic CT. Bronchiolitis obliterans may also be more diffuse, typically appearing as mosaic perfusion and multifocal lobular low attenuation on inspiratory imaging, proven to reflect air trapping on post-expiratory imaging; however, this appearance is not consistent with the morphology seen at this patient’s thoracic CT. Therefore, another process may account for the patient’s presentation.
At this point, which of the following tests would be most useful for establishing the diagnosis for this patient? (Click on the correct answer to proceed to the seventh and final panel)