Pulmonary congestion is a common finding of volume overload or volume shift in heart failure (HF) and its detection is essential to facilitate timely therapy initiation or adjustment prior to frank decompensation requiring hospitalization. Traditionally, the most often utilized clinical evaluation methods have been assessment of patient symptoms, the physical examination, and chest radiography (CXR). However, these approaches are either insensitive or difficult to use at the patient's home or in the outpatient setting.