What is it?
The
IMT (Intima Media Thickness) scan
is a high resolution vascular ultrasound which
measures arterial wall thickness and its character.
IMT refers to a measurement of the first two layers
of the carotid artery. The measured
thickness is a marker of early atherosclerosis and
its progression.
How is an IMT scan performed?
 During
an IMT scan, an ultrasound technician will glide an
ultrasound probe over the skin of the neck,
carefully surveying the carotid arteries using
high-resolution computer imaging. This process takes
about fifteen minutes and is completely noninvasive.
The images are analyzed with IMT software that
automatically detects the edges of the vessel wall
layers and measures them. Then, this data is
compared with a database to reveal the patient’s
risk relative to large population-based studies’
normative values for the same age, race and gender.
The report can accurately assess the presence of
disease, predict cardiovascular events and evaluate
the progression or regression of disease before
there are symptoms.
Research
SonoSite “An Ounce
of Prevention” article
Article:
www.sonosite.com/primarycare
“ At the Heart
Prevention Clinic of Idaho, Dr. Bryan Pogue and
his lipidologist partners are tackling
cardiovascular disease by maintaining an intense
focus on preventing and even reversing disease,
rather than waiting to correct its consequences”
quoted a 2007 article published by SonoSite. In
the article, the fact that the medical community
as a whole is shifting toward earlier and more
aggressive preventative care is stressed, which
highlights the value of IMT and Cardiovascular
risk profiling. Dr. Pogue’s co-authorship and
investigation in the landmark OPACA (Office
Practice Assessment of Carotid Atherosclerosis)
Study sponsored by SonoSite is also mentioned.
Statins at McDonald’s
Article:
www.medscape.com/viewarticle/726921
An article presents the
new proposal from British cardiologists that
statins, medication aiming to offset fat found
in unhealthy meals, be offered alongside
condiments at fast-food resturaunts. Dr. Darrel
Francis (Imperial College London, UK) said, “ If
patients need to see a doctor before they take a
statin, then how come they don’t need medical
advice to eat a hamburger?”. One risk
that bothers Francis is that patients might
begin to think that they can eat larger
quantities of whatever they want with the
addition of the statin. Some cardiologists
disagree with the proposal based on the fact
that cardiovascular disease is based on multiple
risk factors, not diet and fat/cholesterol
control alone. Others say that doing something
good to counteract something negative only to
end with a neutral result is not worth it. Dr.
Dariush Mozaffarian (Harvard School of Public
Health, Boston, MA) said, “ We want to
maximize the good. If somebody needs to take a
statin, and they benefit from a statin and are
compliant with that statin, then they should
take the drug and gain the benefit, and they
should also focus on gaining the benefit from a
healthy diet. Why would you not want to do both?”.
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Carotid Artery
The common carotid arteries (CCA) supply
blood to the head. Each artery branches into the
external carotid artery (ECA) and internal
carotid artery (ICA). The ICA supplies blood to
the brain. The area where these two arteries
split is called the bulb. In an IMT scan, the
areas of interest are the CCA, ICA, and the
bulb.
Why the Carotid artery?
Studies have indicated that by using the
averate IMT of the Carotid arteries, we see a
mirror to the heart and its condition. In other
words, if something is happening in your carotid
arteries (plaque build-up, for example), it is
happening in your heart as well.
What is plaque, what
does it do?
If an IMT measurement is
greater than 1.2mm in thickness, it is
because of fatty build-up and considered a
“plaque”. This plaque can continue to grow
which will cause narrowing (stenosis) of the
artery. This restricts blood flow. Plaque
also has the potential to rupture the artery
and enter the blood stream, causing a
stroke.
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