Cross-sectional echocardiography: physical principles, anatomic planes, limitations and pitfalls.

Although M mode echocardiography has achieved a prominent role in the diagnosis and management of patients with cardiovascular disease, the limited area of view afforded by M mode techniques has restricted the application of ultrasound in many areas. The development of two dimensional echocardiography has obviated many of the limitations inherent in the narrow view of the M mode technique. It has enabled imaging of the heart from additional transducer locations, permitted determination of shape and anatomy and provided the ability to determine motion along two axes. Several types of two dimensional echocardiographs have been developed, and each type offers both advantages and disadvantages. Although two dimensional echocardiography has provided a larger area of view with ultrasound, it has also introduced new limitations including a larger and bulkier transducer, a much reduced sampling rate and a difficult display medium (videotape). In addition, new considerations regarding ultrasonic resolution have been raised. Two dimensional techniques have resulted in new pitfalls in ultrasonic diagnosis related to instrument artifacts as well as to performance and interpretation of the examination. The spurious appearance of cardiac masses because of these ultrasonic artifacts represents a particularly prominent diagnostic pitfall that must be avoided in daily practice. It is anticipated that the new wider field of view provided by two dimensional echocardiography combined with a standard high resolution capability of ultrasound (2 to 4 mm) will result in an increasingly large role for echocardiography in the management of patients with heart disease.