Oh- Ech o ch01.tex V1 - Jul y 20, 2006 6:1 4 P.M. Page 1 1 How to Obtain a Good EchocardiographyExamination: Ultrasound Physics, Technique, and Medical Knowledge The burgeoning technol ogic revolution of the past two dec ade s hasproduc ed a continuousevolu tionin thedefini - tion of a complete and comprehensive echocardiographicevaluati on (Fig. 1-1). Echocardi ography is now a fullyFIG1.1 grown tree. It has numerous clinical applications, with var- iousforms of ultras oundtechnologybeing usedthroughoutthe entire field of cardiovascular medicine. This mature ul- trasound tree has grown from a seed planted more than 50 years ago. Since then, the tree has been trimmed and nourished carefully by many pioneers to serve the needs ofpatients and clinicians. In 1954, Edler and Hertz (1) of Sweden were the firstto record movements of cardiac structures, in particular, the mitral valve, with ultrasound. In the early 1960s in the United States, Joyner and Reid (2) at the University ofPennsylvania were the first to use ultrasound to examine the heart. Shortly afterward, in 1965, Feigen baum and col lea gues (3) at Indi ana Uni ver sit y report ed the firs tdetec tion of pericardial effusion with ultras ound and were responsible for introdu cing echoca rdiograp hy into the cli nic al pra cti ce of car diol ogy. Howeve r, M-mode echocardiography produced only an ‘‘ice pick’’ view of the heart;two-dimensi onal (2D) secto r scanni ng, develo ped in the mid-1970s, allowed real-t ime tomographic images ofcar diacmorphol ogyand functi on(4). Thefirstphase d arra y2Dsector sca n atMayo Cli nicwasmade onMarch17, 1977. Altho ugh the development of Doppler echoca rdiogra phyparalleled that of M-mode and 2D echocardiography from the early 1950s, it was not used clinically until the late 1970s. Pressure grad ients acr oss a fixe d ori fice could be obtained reliably with blood-flow velocities recorded by Dopple r echocardiogr aphy. Two groups, Holen and colleagues (5) and Hatle and colleagues (6), should be credi ted for introdu cing Doppler echoc ardiogra phy into clinical practice. Numero us validati on studie s subseq uently confirmed the accuracy of Doppler echocardiography in the assess- mentof cardia c press ures.Therefore, theDoppler techni que made echocardiography not only an imaging but also a hemodynamictechnique.On thebasisof theDopple r con- cep t,colorflowimaging wasdeve lope d inthe ear ly1980sso that blood flow could also be visualized noninvasively (7).
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Figure 1-1 Echocardiography has become a mature tree thathas numerous branches and is still growing. CFI, color flowimaging; ICUS , intracardiac ultrasonography; I-Op, intraoperativeechocardiography, IVUS , intravascular ultrasonography;TEE , trans-esophagealechocardiography;3D/4D, three- and four-dimensionalechocardiography.
Another ingenious modification of Doppler echocardio-
graphy was tissue Doppler imaging (TDI), which allows
echocardiographers to record myocardial tissue velocity
and to measure the extent of myocardial deformation as
of the endocardial border. If the image quality is not opti-
mal in spite of all measures, including harmonic imaging,
then a contrast agent should be injected intravenously to
improve the definition of the endocardial border. Because
intravenous accessis required,a qualified memberof an in-travenous team should be available to start an intravenous
line as soon as contrast echocardiography is needed.
SCREEN DISPLAY AND KNOB SETTINGS
How best to display echocardiographic images on the
screen is a personal choice and should be choreographed
Figure 1-3 Still frame of a typical echocardiography monitorscreen. It is essential for the screen to display the patient’sidentification, blood pressure (BP ), and cardiac rhythm. The typeof transducer, field depth, color map, and other machine settingsare also displayed. In the example here, the BP was 120/52 mmHg, with a wide pulse pressure. Aortic valve shows doming (arrow )during systole (a break in the ECG at the bottom indicates thetiming of the image on the screen), with moderately severe aorticregurgitation that explains the wide pulse pressure. ‘‘H3.5 MHz’’indicates harmonic imaging with a 3.5-MHz transducer. Field depthis 160 mm (this information is important in stress echocardiographyand other quantitative studies for which the same depth isdesired for all images). ‘‘MI’’ indicates mechanical index, whichis an essential function in contrast echocardiography. ‘‘Store inprogress’’ indicates that the echocardiographic images are storeddigitally while the phrase is shown on the screen; thus, desiredimages need to be maintained during this period. HR , heart rate.
according to the clinical objectives of the examiner.
The following should be shown on the screen: the
patient’s identification, blood pressure at the time of theexamination, and a sharp electrocardiographic tracing with
prominent R and A waves (Fig. 1-3 and 1-4). Depth, size,
FIG1.3
FIG1.4
and gain settings of the ultrasound images need to be
adjusted frequently during the examination. To develop
an initial impression of the overall cardiac structure and
Figure 1-4 Initial parasternal long-axis view with an imagingdepth of 24 cm (240 mm on screen) demonstrating a large pleuraleffusion (PL) andpericardialeffusion(PE ). Lesionsin thedescendingaorta (*) can also be appreciated with a long imaging depth. LA,left atrium; LV , left ventricle; RV , right ventricle.
systolic pressure. Typical echocardiography reports from
the Mayo Clinic laboratory are shown in the Appendix.
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