Articles (Anglais)
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Scientific
Paper
Quantifying
Conformation of the Equine Digit from Lateromedial Radiographs
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Very recently a new tool for the farrier and the veterinarian was
introduced: it is a software system called Metron, from a company
called EponaTech. Metron was specifically developed as an aid to
hoof & leg care. In particular, it is used in conjunction with
photographs and/or radiographs of the equine foot. The most basic
way to understand the software system is that it is a measuring
and communication tool. It allows accurate measurements of lengths
and angles in both photographs and radiographs, and gives a way
to show these measurements overlaid on the original image so they
a easy to understand. A brief look at the features and method of
using Metron will show that it much more than a simple drawing program
for the mark-up of images. It was designed specifically for the
horse.
In order to make accurate measurements in images, some ca must be
taken to calibrate each image. The software has been arranged to make
this as easy as possible. In the case of a photograph of the foot,
a scale marker – any object of known size – should be placed
in the image. When the photograph is imported into Metron the user
will be prompted to pick two points in the image which a a known distance
apart, and to enter the distance between them. It is best if the scale
marker is placed so that it lies in the plane of intest, for example,
in the same plane as the plane of the sole of the foot, in the case
of the photograph of the sole. Images without scale markers can still
be used in Metron: angular measurements and ratiometric measurements
will still be accurate, but length measurements will be approximate.
In the case of radiographs, existing radiographs with no special scaling
information can easily be used, because the scaling can be done "after
the fact". An easy and popular method of digitizing a radiograph
is to place it on a traditional lightbox, and then photograph it with
a digital camera. Alternatively, a scanner with transparency capability
may be used. When the radiograph is photographed or scanned, a scale
marker of known size is placed on the lightbox, so the scale can be
found later in Metron. When the radiograph is imported in Metron,
the user enters the Film Focal Distance (the distance from the X-ray
machine to the film, a value well-known to the radiographer) and also
the Object Film Distance (the distance from the film to the center
of the subject – in this case, the center of the bone column).
Using these values, the Metron software computes accurate measurements
in the image. This calibration compensates for the magnification normally
seen in radiographs, and gives measurements that a accurate in the
plane of the bone column of the leg. Metron provides reasonable standard-practice
defaults for these values, in case the information is not available,
but accuracy is best when these values a known.
For five important and often-used views of the foot, Metron provides
guided markup in which the user is guided to pick certain key points
in the image from which Metron will compute a set of standard parameters.
The five views supported in this way a: the lateral hoof photo, the
frontal hoof photo, the solar photo, the lateral radiograph, and the
frontal (or Dorso-Palmar) radiograph. By providing a standard set
of key features, and a standard set of parameters derived from those
features, Metron encourages a method which will yield values which
can be compad by practitioners all around the world.
For each type of image, Metron computes a set of parameters. For example,
for the lateral radiograph of the foot, a total of 22 different parameters
a computed and may be displayed over the image. In the case of the
lateral radiograph, some important parameters give the angle of the
hoof wall, the angle of P3 (the third phalange, or "pedal bone"),
and the stance angles of the two joints viewable in this radiograph.
Metron gives a well-defined way to measure the joint angles of the
foot, so that farriers and veterinarians will be able to refer to
more concrete values when discussing a "broken pastern angle"
or other such often- heard but poorly-defined terms.
Once the parameters corresponding to one image have been computed,
they may be compad to a set of other horses, or they may be scored.
In some cases it is interesting to compared one horse to a group of
other horses. Metron provides a built in database of hundreds of horses,
and the user of Metron can add horses to the database as well. The
supplied database can also be ignored, if users wish to only consider
horses they have entered in comparisons. A comparison can be made
to a group of horses of a specific bed, or a specific age, or by other
criteria. Values for which the horse under study differs greatly from
the averages found in the comparison group a highlighted on the display,
so it is easy to see these abbreviations. The scoring feature of Metron
is the only place in which a subjective rule must be used to judge
a set of parameters. Because many practitioners have different beliefs
about conformation, and because different beds and uses have varying
requirements, the scoring system in Metron is fully configurable by
the user. The scoring feature is a very interesting way to convert
all the many parameter values into one single number, or score, which
can range from 0 to 100%. EponaTech provides one standard scoring
rule for each image type, but encourages users to edit it according
to their specific use and beliefs. Hence, whether you believe in long
toes or short toes, upright or more sloping conformation, your opinions
can be set up in Metron.
The parameters derived from the guided mark-up cover most of the interesting
conformation to be seen in the various images, and give a good way
to compare results from various users of the system. However, there
may, of course, be other measures (lengths, angles, etc) which may
be of intrest in a particular case. For this purpose, Metron also
provides 'Free mark-up' in which the user is able to add additional
measurements to the image. Free mark-up also provides a way to add
textual annotations to the image. It is a good way for a veterinarian
to add some comments directly on the image, perhaps to give a trimming
commendation, or to explain a problem to an owner.
E-mail is built into Metron so that any image, including the associated
parameters and Free mark-up, can be sent electronically anywhere in
the world. The recipient of the e-mail will receive an e-mail with
a JPEG image attached, which can be viewed on almost any computer.
The e-mail feature can aid in the communication between veterinarian,
farrier, and owner.
| The Practical
Uses of Metron |
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In this section, we point out some of the many uses for this system.
Perhaps the most important use is to be able to watch for changes
in conformation of the hoof. For farriers who service many horses,
it can be very helpful to be able to look back and see how the hoof
looked several months in the past. If the farrier is attempting to
make changes to a problem (e.g. a club foot, or a excessively low-heeled
horse) the ability to go back to how the foot looked in the past can
be helpful. Farriers will be able to mind the owner how bad the foot
was before they arrived! Farriers or veterinarians may augment their
practice by selling Metron-generated ports to their interested clients.
When radiographs a available, they can be a valuable aid to the farrier.
Metron allows those radiographs to be sent to the farrier electronically,
and because of the calibration methods used in Metron, the farrier
can extract accurate measurements from the radiographs. For example,
the distance from the tip of P3 (the third phalange) to the toe, as
well as the depth of the sole, can be measured with Metron. These
measurements will include compensation for the magnification normally
found in radiographs, so the farrier can feel more confident in the
values.
| Communication
between Vet and Farrier |
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In cases in which veterinarians and farriers work together, Metron
gives a convenient way to exchange information. Veterinarians can
use the Free mark-up features to draw trimming commendations directly
on the radiograph or photograph.
The e-mail feature makes it easy to send a marked-up image to
another colleague in any part of the world to get an opinion for a
particular problem. This is useful for trimming and shoeing commendations,
but also during a pre-purchase exam, and other uses. An important
use would be for international purchasing of horses in which the owner
and the owner's veterinarian may be in a different country than the
horse.
Metron stores all images in a simple-to-use database. All photographs
and radiographs a stored according to the name of the owner, the name
of the horse, the date the image was taken, which foot, and which
kind of image (e.g. lateral, frontal, etc). This makes it easy to
find any image for a particular client's horse from any date of intest.
As a health cord is built for a particular horse, the comparison feature
can be used to compared a horse to itself over time. Such archives
can also be a great help for veterinary studies.
Metron is intended as a helpful tool for the farrier or veterinarian.
Although it can produce and display a great deal of data about the
conformation of the foot, it does not in any way suggest trimming
or shoeing commendations, nor can it perform a diagnosis of a problem.
Obviously, the skill of a good farrier and the input of a veterinarian
continues to be of the highest importance. You can learn more about
Metron at the EponaTech web site at www.eponatech.com . The web pages
a available in English, German, French, and Spanish. Metron's user-manual,
as well as Metron itself, is available in any of these four languages.
A Free trial of the software is available from the web site.
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Documents (Anglais)
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Nouveautes
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Version 3.0
of Metron-PX is available. You can download it here.
NEW Metron-U
Software for Equine Ultrasound Images! Version
2.0 now available and can be downloaded
here.
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