NHSN does not offer an all-inclusive list of pulmonary and cardiac conditions that require serial imaging. Certain underlying diseases or conditions may make interpretation of the imaging test findings difficult, and the purpose of serial imaging is to ensure the imaging findings for these patients are due to pneumonia and not a reflection of the underlying disease/condition. This would include conditions such as COPD, CHF, bronchopulmonary dysplasia (BPD), respiratory distress syndrome (ARDS/RDS), etc. Conditions that do not typically present with imaging findings that could make evaluation of imaging for pneumonia difficult (such as hypertension, asthma, etc.) would not be included as underlying pulmonary or cardiac disease that require serial imaging.