When preparing to get scanning, the first thing that
you need to look at is the machine that you're using.
There are various types of machines that are available to perform
an ultrasound examination in cattle.
This particular
machine has the
console and the probe
which is attached. The viewing device, so what you actually see the image on, is either an
external monitor or a set of goggles. There is also a wrist display.
On other machines
these may all be combined onto
one console. Some of them may be more stationary, while this one you can wear on your hip and walk around with you.
You also have the probe and this is what actually acquires the image.
When looking at what you can adjust on the machine to improve the quality of
the images that you're
achieving, there are three main things that you need to be able to alter.
The first is the frequency.
The frequency will affect whether you're looking at something in the superficial or near field,
so things that are very very close to the surface of the probe or things that are further away.
So an example of this,
of something that would be in the near field would be an early pregnancy or an ovary.
Something that would be
in the more far field, further away from the surface of the probe, would
be a later term pregnancy or in a multiparous cow,
whose uterus has been stretched to be on the pelvic brim instead of being intra-pelvic.
When looking at the frequency that you set the machine at, a
higher frequency range will give you a clearer picture, better resolution of things that are in that superficial or near field,
like an early pregnancy or an ovarian structure.
If you looking at later term pregnancy or a uterus that is potentially a bit deeper down within the pelvis,
you would be wanting to use a lower frequency setting.
Another feature that you can change is going to be the depth. Again if you're looking at things that are in the very superficial field
or things very near to the surface of the probe, such as an early pregnancy or the ovary, you
would have the depth
at a more superficial setting, so you wouldn't be looking as deep.
If you are looking at things that are further down
within the cow,
such as a later term pregnancy, then you would need to have the
depth set at a greater number of centimetres.
The final thing that you need to be able to change is the gain setting.
The gain is the overall brightness of the image that you're viewing.
When you set the gain, be a bit cautious about how high you turn that up because it will amplify
or make louder, more bright,
not only the true signal but also any noise that you have within the image.
So you want to ensure
that you're getting a clear picture of the actual structures within the cow.
So you need to look at your frequency, your depth and your gain settings.
On this particular machine
the frequency and the depth
are both set within individual modes. On this machine there are four different settings,
the ovary/ early mode, detail mode and foetal sexing modes are all looking at structures that
are in the more superficial
or near field, otherwise they are very near to the
surface of the probe.
Therefore, they will be looking
at a decreased depth as they are closer to the surface of
the probe when it's in the cow and you will also be wanting
to have a clearer picture in that superficial field.
So, when you're in an ovary/early mode, what you'll
be looking at is higher frequency setting and a
decreased depth.
When you're looking at the late mode on this particular machine,
what it will be changing
is the frequency down to a lower frequency, as we are wanting to get enough penetration down
deeper within,
within the cow
and it will also be increasing the depth as well.
So when looking at things in the very near field, such as an early pregnancy or an ovary, you would
want to have it on a higher
frequency setting and a
decreased depth, because you are looking at things that are just underneath
the surface of the probe.
When you're looking at things that are further away from the probe,
where you need the ultrasound wave to penetrate a bit deeper down, you will set it on a lower
frequency and
an increased depth.
So those would be things, such as a later term
pregnancy or a multiparous cow
that has the uterus that has stretched beyond the brim of the pelvis.