Many veterinary practices now have ultrasound equipment for pregnancy and tendon scanning. Unfortunately this equipment is seldom suitable for echo-cardiography. As discussed in the previous section, equine echocardiography is best performed with a low-frequency sector scanner. A frequency of 2.0-3.0MHz is suitable, although a 3.5 or 5.0 MHz transducer may be best for echocardiography of foals because the penetration is adequate and resolution is improved.
A number of other features are important considerations in selection of suiequipment. These are summarised in Table 4.5. Most practices will be forced to compromise when selecting an ultrasound machine, but a suitable frequency and depth display are essential if effective echocardiography is to be performed. Ultrasound machines used for echocardiography should have an
mode facility which can be selected rapidly rather than via a complex menu. Machines should also be equipped with ECG leads and ECG display. This is particularly valuable for making measurements at specific times of the cardiac cycle and for interpreting spectral Doppler. A foot pedal for freezing frames or for switching from 2DE to M-mode is very helpful.
Ancillary equipment is also important. The most important of these is a good quality video recorder which is required unless a cine-loop facility is available on the ultrasound machine. A video tape recording is the best means of recording hard copy for later analysis or comparison with other studies because the real-time image is much easier to interpret than a still frame. Other forms of hard copy are also available. Equipment for Polaroid photography is relatively cheap but each image is quite expensive. Multi-format cameras provide good quality images but are expensive both in terms of capital and running costs. A video printer is cheaper if more than a few images are to be made and is ideal for most practices.