Artifacts and anatomical variants affecting ventilation and perfusion lung imaging

Ventilation and perfusion lung imaging continues to be an important technique in the investigation of lung disease, particularly pulmonary emboli. For the most accurate interpretation, a solid understanding of the agents available, underlying physiology, and normal variants is required. A number of ventilation agents are available ranging from true gases to aqueous aerosols and carbon nanoparticles. The addition in recent years of SPECT imaging, although improving the technique, has added to the range of artifacts and variants to be appreciated. In addition, there are uncommon conditions that can affect the scan appearance. A selection of these variants and artifacts is discussed in this article.