CIMT Ultrasound Explained
Do you have a cat in the gutter?
In the photo above, the pigeon is minding its own business with no idea that death is about to pounce. You are the pigeon; unknown vulnerable plaque in your heart or carotid artery is the cat. Arterial plaque looms without symptoms, and without warning can pounce to change your life forever!
Plaque typically begins to form years or even decades before a heart attack or stroke occurs. Cholesterol particles pour into the wall of the artery as shown above and plaques begin to grow beneath the surface like an iceberg. Plaques then bubble up from the surface like a volcano that is waiting to erupt. These volcanoes are vulnerable plaques. Heart attacks and strokes are caused by rupture of vulnerable arterial plaque; an eruption of the volcano.
Optimal Screening
All existing vascular plaque needs to be stabilized to prevent a heart attack or stroke. Optimal treatment will also prevent further growth, and quite possibly reverse the process. Early plaque is much more common than most realize. However, finding early plaque can be very difficult. The following tests are used to identify disease before it causes a problem.
Cardiac stress test- This is the most common form of testing, but is very inadequate. A stress test will only show a problem if a plaque is so big that it blocks 2/3 of the blood flow. 70-86% of heart attacks occur in vessels with less than a 2/3 blockage! A normal stress test is frequently a false reassurance that you are safe.
Standard carotid ultrasound testing- Like a stress test for the heart, this only measures blockages of flow in the carotid artery of the neck. Small, yet dangerous plaques will never be seen.
Coronary Calcium Scoring (also known as Ultrafast CT scan of the heart) – This test has been available since the late ‘90s and is much better screening tool than either of the above flow studies. It uses the radiation of a CAT scan to look for plaque in your heart that contains calcium. It will find plaque that is not yet obstructing flow. It’s weakness is that many vulnerable plaques do not contain calcium.
Carotid Intima-Media Thickness (CIMT) ultrasound- CIMT is the best method to detect early disease. It is much different than carotid ultrasound screening described above. CIMT uses modern ultrasound technology together with advanced software capability to measure the thickness of arterial walls. It is extremely valuable to:
- Detect advanced thickening that is reversible if treated appropriately.
- Detect individual vulnerable plaques that do not contain calcium. These are the “cats in the gutter”.
A 2009 study published in the Mayo Clinic Proceedings performed CIMT ultrasound on 36-59 year olds who only had one cardiovascular risk factor. It found that 34% had plaque! Many of these unsuspecting people will have an event, or need stents/bypass in years to come. Half of those found to have plaque on CIMT had a calcium score of zero. This is not surprising since soft plaque, the most dangerous type, does not contain calcium.
In the United States, we have been very effective at treating disease once an event occurs or it gets advanced enough to cause symptoms. We have been very ineffective at proactively preventing or reversing early disease. CIMT ultrasound allows us to find disease very early, search for the causes, and treat them aggressively. Treatments include appropriate lifestyle changes, meds, and supplements. It also includes treatment of root causes like sleep apnea, periodontal disease and insulin resistance. Disease found early is reversible. Improvement can be tracked by CIMT ultrasound.
CIMT is newly available to the public. A March 2011 task force report published by the American College of Cardiology touted CIMT ultrasound as a very valuable screening tool. They only cautioned about the quality of the test. We will ensure that you receive a quality test.
Who should be screened?
Knowledge is power. Anyone with even one vascular risk factor should be screened. The Mayo Clinic Study showed that many young people with just one risk factor had plaque.
We strongly recommend it for anyone with a family history of heart attack, stroke, or dementia. You should be tested if you have a traditional risk factor like high cholesterol, high blood pressure, obesity, or smoking. We also strongly recommend it for anyone who has one of the root causes of vascular disease like pre-diabetes, sleep apnea periodontal disease, and any of the inflammatory diseases (rheumatoid arthritis, psoriasis, inflammatory bowel, others). Every man over 40 and woman over 50 should consider having it.