Introduction to Imaging
The Normal Examination
Dara Lee, MD and Scott D. Solomon, MD
Two-Dimensional, M-Mode, and Doppler Echocardiography Echocardiographic Views The Parasternal Position Apical Position Subcostal Position Suprasternal Position Summary
A 30-yr-old pregnant woman is referred for an echocardiogram to evaluate a heart murmur. She has no significant medical problems and is in the third trimester of an uncomplicated pregnancy. The systolic murmur was noticed on a routine obstetrical examination; the patient has no complaints of dyspnea, chest discomfort, or palpitations. She walks daily without limiting cardiac or respiratory symptoms. She has no history of rheumatic fever and has never been told of a heart murmur in the past.
As expected, the study is entirely normal. The most likely cause of the patient's murmur is the increased intravascular volume expansion associated with third trimester pregnancy, which often leads to a benign "flow murmur." Such a murmur may be auscultated in other states of increased flow across a normal valve, such as fever or hyperthyroidism.
two-dimensional, m-mode, and doppler echocardiography
The basic principles of echocardiography, including the basics of physics and instrumentation are discussed in Chapter 1. This chapter is an introduction to the echocardiographic examination, and a detailed description follows in Chapter 3.
Two-dimensional (2D) images form the basis of the echocardiographic study, providing structural and functional information as well as guiding the use of M-mode and Doppler techniques. The tomographic images described next constitute the 2D study. As discussed in Chapter 1, ultrasound waves generated from the ultrasound transducer travel to the heart and are then reflected back to the transducer. Returning ultrasound waves are analyzed for depth location (based on the time elapsed between signal emission and return), and density (denser structures will reflect a greater proportion of the ultrasound beam than less refractile objects). Figures 1 and 2 demonstrate a 2D image from the parasternal long-axis (please see companion DVD for corresponding video for Fig. 1).
From: Contemporary Cardiology: Essential Echocardiography: A Practical Handbook With DVD Edited by: S. D. Solomon © Humana Press, Totowa, NJ
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