American Board of Surgery Qualifying Exam (ABS QE) Practice Test

In chronic lung transplant rejection, what is often seen on imaging studies?

1. Ineffective ventilation

2. Interstitial fibrosis

3. Air trapping

4. Vasculopathy

The correct answer is: Air trapping

In chronic lung transplant rejection, imaging studies commonly reveal interstitial changes related to the underlying pathophysiology of rejection. These changes often include progressive lung injury where the lung parenchyma becomes fibrotic. Patients can develop bronchiolitis obliterans syndrome (BOS), which is characterized by air trapping due to the obstruction of small airways. This air trapping can be visualized on imaging studies such as CT scans. The imaging exhibits hyperinflated regions resulting from the inability to expel air effectively during expiration, which often manifests as hyperlucent areas. The presence of air trapping indicates that there is a component of airway obstruction that contributes significantly to the respiratory difficulties experienced by the patient. Understanding this aspect of chronic lung transplant rejection helps contextualize the process behind the imaging findings. While interstitial fibrosis, vasculopathy, or ineffective ventilation can be related to other pulmonary conditions or complications, air trapping is specifically associated with the obstructive phenomena seen in the context of chronic rejection post-lung transplantation. Hence, it serves as a pivotal indicator in the evaluation and management of these patients.