Level 1 Diagnostics’ Carotid Ultrasound

Overview

No one else is doing what Level 1 Diagnostics is doing with carotid ultrasounds for preventative medicine. Level 1 Diagnostics ultrasound is able to identify what part of a plaque is calcified and what part is soft plaque, versus blood in the artery, thereby accurately identifying the presence of a vulnerable plaque.

Level 1 Diagnostics uses advanced technology called Sequential Analytics, whereby 30 frames or more per second are captured for as long as it takes to film the entire carotid in both the sagittal and transverse planes. Each frame is evaluated for disease by highly-trained specialized technicians using advanced software. These results are then over-read by radiologists, providing our doctors with the finest information available.

The Problem

In most instances plaques are present in the carotid artery because cardiovascular disease is a systemic disorder (throughout the entire circulatory system). In order to be evaluated by a Cardiologist you must have significant risk factors or have had an event—such as a heart attack or a stroke.

An angiogram is the gold standard for plaque evaluation. A stress echo or a nuclear stress test is specific to coronary arteries and is most often used to detect a decrease in blood flow to the heart from narrowing in the coronary arteries. Without major symptoms, a Cardiologist cannot order these tests preventively to rule out cardiovascular disease. Also, even if someone had an event and then had a stent, that does not stabilize other plaques that are present.

Traditional ultrasound is not geared towards preventative medicine. The traditional medical picture archiving system is called dicom. These are very large files whereby a sonographer takes a picture of a lesion to show the doctor. This was developed for patients who had an event and the doctor needs to find the cause and treat it.

Traditional ultrasound includes Doppler. Doppler is a mode of ultrasound that uses blood flow to help doctors make an educated guess about percent stenosis (how much of the artery is blocked). This only applies to the internal carotid artery. It is only relevant to the external carotid if there is a complete occlusion and to the common carotid if there is an 80% occlusion. Even when carotid intima-media thickness levels were less than 1 mm, more than 30% of people demonstrated mixed or soft plaque, potentially prone to rupture.

The Solution

Level 1 Diagnostics ultrasound protocol evaluates in both “A” and “B” mode.

  • “A” mode (Amplitude) is a graphical representation of tissue density within a structure.
  • “B” mode (Brightness) is a traditional 2-dimensional slice.
  • Both “A” and “B” mode are required to ascertain plaque stability.

Level 1 Diagnostics is interrogating the internal, external, and common carotid.
The external carotid feeds blood to the face. The internal carotid feeds blood to the brain. The common carotid feeds to both the internal and external.

Level 1 Diagnostics has the technology to evaluate plaque vulnerability in the common carotid, which no other ultrasound is able to do.
With the Level 1 Diagnostics protocol the bulb in the common carotid is visualized and this is a place where vulnerable plaque might be seen.

Level 1 Diagnostics looks at the carotid in both the sagittal and transverse planes.
Most plaques reside on the sides as well as the top and bottom of the artery wall. Scanning and recording in real time the transverse plane from the bottom of the neck to the bulb reveals the tiniest plaque. The sagittal view is necessary to get an accurate measurement of the thickness of the artery wall over the length of tissue. Therefore, it is necessary to have both views. It is also a way to visualize other vascular pathology. 


Plaque Character

The primary purpose of the Level 1 Diagnostics ultrasound is to accurately determine the likelihood of the presence of cardiovascular disease based upon the thickness of the intima-medial layer of the common carotid artery wall, relative to a patient’s age and gender. If during the evaluation one or more plaques are identified, the question no longer is whether the patient has cardiovascular disease, but rather, what is the likelihood that the plaque could rupture, leading to a stroke or heart attack?

The Plaque Composition Profile accurately measures any plaques that may be found in the carotid arteries and is displayed graphically as seen here. This data can be compared with future scans to monitor the progression or regression of disease. The character of the plaque is represented by a numeric value with a higher value representing plaque that is more calcified and lower values representing soft or mixed plaque that may have a greater vulnerability to rupture:

  • value less than 50 represents fluid
  • value between 50 and 200 represents soft/mixed plaque
  • value over 200 represents calcified plaque

According to a major study in the July 2017 ed. of American Journal of Cardiology: It is important to assess plaque when doing a carotid ultrasound

Even when CIMT (carotid intima-media thickness) levels were less than 1 millimeter, greater than 30% of persons demonstrated mixed or soft plaque potentially prone to rupture. Of those with CIMT greater than or equal to 1 millimeter, more than 70% had such mixed or soft plaque and over 40% demonstrated stenosis (abnormal narrowing of a passageway) of 30% or greater.

We describe in a large CIMT registry study a substantial age-related increase in both men and women of increased CIMT, plaque presence and severity, as well as stenosis. Even in those with normal CIMT, mixed or soft plaque was common, further demonstrating the value in assessing for plaque when doing carotid ultrasound.*

* The explanations in parentheses were added to the original quote by Level 1 Diagnostics.

What Your Scans Will Reveal

  1. Plaque Character and Plaque Vulnerability –type of plaque seen
    1. There was no plaque seen in the artery.
    2. There was hard plaque seen in the artery which will continue to build up over time leading to an increase in atherosclerosis.
    3. There was soft plaque seen in the artery which is vulnerable to rupture.
    4. There was mixed plaque seen in the artery, but the hard plaque appears to be stable.
    5. There was mixed plaque seen in the artery, but the hard plaque is anchored by soft plaque making it vulnerable.
  2. Carotid Intima-Media Thickness (CIMT) – a well-established predictor of cardiovascular disease events.
    1. The results of the IMT measurement was less than 0.8  mm, therefore inconsequential at this time.
    2. The results of the IMT measurement was between 0.8–1.0 mm and shows early evidence of cardiovascular disease.
    3. The results of the IMT measurement was greater than 1.1 mm which is predictive of systemic cardiovascular disease.
  3. Stenosis – abnormal narrowing of the carotid artery
    1. There was no stenosis seen in the artery.
    2. There was mild stenosis seen in the artery.