Page 450 - WSAVA2018
P. 450

     448
WSV18-0040
NUTRITION AND DIAGNOSTIC IMAGING (LECTURES GIVEN IN MANDARIN CHINESE)
THE THORAX EXAMINED BY RADIOLOGISTS - HOW TO AVOID MAKING MISTAKES
H.G. Heng1
1Purdue University, Department of Veterinary Clincial Sciences, West Lafayette, USA
NEW SONOGRAPHY TECHNOLOGY IN VASCULAR IMAGING
Hock Gan Heng, DVM, MVS, MS, DACVR, DECVDI
Purdue University, Department of Veterinary Clinical Sciences,
625 Harrison Street, West Lafayette, IN 47907, USA hheng@purdue.edu
Doppler Effectis a change in frequency (and wavelength) caused by the motion of a sound source, reflector and receiver. If a reflector is moving toward the source and the receiver, the received echo of the reflector has a higher frequency than would occur without the motion. On the other hand, if the motion is away from the source and the receiver, the received echo of the reflector has
a lower frequency. The amount of the frequency change depends on the speed motion of the reflector, the angle between the wave propagation, direction and the motion direction, and the frequency of the wave emitted by the source. The change cause by the motion is called the Doppler-shift frequency or Doppler shift. The Doppler shiftdepends on the speed of the reflector and the frequency of the source. It is the difference between the frequency of the source and the returning frequency recorded by the receiver.
In medical ultrasonography, the reflector is the cells in the blood stream, and the source and the receiver is
the transducer used in the examination. The Doppler Effectis a result of the motion of blood. A maximum positive Doppler shiftoccurs if the direction of the sound propagation is exactly opposite the flow direction. A maximum negative Doppler shift occurs if the direction of the sound propagation and the flow direction is similar.
If the flow is perpendicular to direction of the sound propagation, the Doppler Shift, no frequency change and thus no Doppler Shiftis detected.
There are three forms of displaying Doppler: Colour Doppler, Power Doppler and Spectra Doppler (tissue Doppler). The Continuous Wave (CW) and Pulsed Wave (PW) PW are display in a form of Spectra Doppler.
Note that the blue colour coded blood vessels represent blood vessels that are flowing away from the transducer (at the top of the image). In the top half of the kidney, they represent renal vein, where the blood flow from
43RD WORLD SMALL ANIMAL VETERINARY ASSOCIATION CONGRESS AND 9TH FASAVA CONGRESS
25-28 September, 2018 | Singapore
What can veterinarians do?
In the UK the Pet Advertising Advisory Group (http://paag. org.uk/) promotes responsible advertising and minimum standards for the online sale of animals. Although voluntary, this at least provides some improvement in advertising and also education via pop-ups, for people looking for a pet online about what to look for to identify a ‘good’ ad. Similar groups have now arisen in other countries. As a profession we should be advocating for a group to be developed in Australia.
Individual veterinarians in practice can have a significant impact by educating the pet owners they see. Good advice includes always seeing both parents when buying a puppy or kitten, and meeting the animal and finding out its history before taking home a relinquished pet. This needs to be case specific. For example, mature people with dog training experience can take home a dog with some behavioural problems, but a young busy family with children under 5 years of age should be counselled not to. Veterinarians can also inform people of the risks of online trade, including scams where there is no pet, receiving a sick or diseased animal, or even receiving an animal that does not fit the breed advertised.
Conclusions
The internet has changed forever the way people
find their new pets. There are reputable breeders
and owners using the internet to advertise their pets. The main problem is for members of the public to be able to easily determine the good from the bad ads. Veterinarians in clinical practice are at the frontline in seeing newly acquired pets, and should include in their history both the location the pet came from and how it was found. Veterinarians also have an important role
in education. Protecting the welfare of pets will help to nurture the human-animal bond which is a great outcome for everyone.
References
1 Hazel SJ, Jenvey CJ and Tuke J. (2018) Online relinquishments of dogs and cats in Australia. Animals 8(2), 25. doi.org/10.3390/ani8020025
2. EU Dog & Cat Alliance®. Online Sale of Pets:
What’s the Cost? Available online: https://www. dogandcatwelfare.eu/news/online-sale-pets-whats-cost/




































































   448   449   450   451   452