Artifacts, pitfalls, and limitations Introduction
The quality of the information obtained from an ultrasound scan is determined by the skill and knowledge of the user, and the ability of the user to recognize and minimize artifacts. This chapter will discuss the most common artifacts encountered in ultrasound of the chest and techniques to avoid these. It should be noted, however, that this is a skill best acquired in real time at the bedside from those experienced in pleural ultrasound. Imaging artifacts can cause misdiagnosis by suggesting the presence of structures that are not present, or by obscuring important structures or pathology. A good example is reverberation artifact, which may give the false impression of adhesions or solid structures in a pleural effusion. If this is not recognized as artifact, it may result in the misdiagnosis of a simple pleural effusion as loculated, so influencing subsequent management decisions. It is essential for clinicians performing bedside pleural ultrasound to have an understanding of common artifacts, how they arise, how to recognize them, and to learn techniques to minimize their effect. Failure to do so may result in clinically significant errors in interpretation. This chapter will also discuss limitations to bedside pleural ultrasound, and pitfalls or errors that are commonly encountered by the novice.