 |
| Fig.1.33 |
There are various displays available in Doppler echocardiographic
systems
(Fig
1.33). The operator sees a normal two-dimensional echocardiographic
image when not in the Doppler mode. When the PW Doppler is switched
on the cursor and sample volume indicator appear along with a
video picture of the spectral display, and the system goes into
an automatic gating mode which, in this case, updates the two-dimensional
image periodically. Notice the location of the sample volume in
the apical four chamber view just below the aortic root. The spectral
displays an obviously aliased flow pattern. The scale factors
on the spectral display indicate the maximum velocity able to
be detected before aliasing occurs.
A hard copy printout of the PW spectral tracing on the screen
is also usually available on most machines from a graphic recorder.
If a CW examination is then performed, the video screen on the
system shows the CW mode spectral display since no imaging is
possible in this mode. The full profile of the abnormal jet may
then be recorded on the screen or by hard copy strip chart recorder.
Of course, higher velocity profiles may be displayed using the
CW approach.
2004