Contrast echocardiography is a technique for improving echocardiographic resolution and providing real time assessment of intracardiac blood flow.
Contrast enhanced ultrasound can dramatically improve ability to detect heart diseases and stratify future risk. The most common use of contrast echocardiography is the enhancement of the endocardial border.
Contrast echocardiography has become an indispensable tool in non-invasive imaging.
Contrast echocardiography is widely used, well tolerated, non-invasive technique employing ultrasound contrast agents such as SonoVue (Bracco. Milan) in order to improve image quality.
Contrast echocardiography exploits the ultrasound properties of micro bubbles, acoustically active gas filled microbubbles, which remain within intravascular space and allow the simultaneous assessment of myocardial structure, function and perfusion.
These concerns prompted the facilitation of contrast ultrasound imaging that utilizes contrast agents.
But, what is contrast media?
Ultrasound contrast agents are liquid suspensions of tiny microbubbles that are biocompatible and biodegradable.
The present generation of ultrasound contrast agents consist of microbubbles of encapsulated high-molecular-weight gas. Contrast imaging utilizes the non-linear scattering properties of ultrasound contrast agents to facilitate their detection within the heart.
The Oscillation
The microbubbles oscillate within the ultrasound beam.
Since the ultrasound characteristics of microbubbles are distinctly different from those of the surrounding blood cells and cardiac tissue, the backscatter that they produce result in intense echocardiographic signals, which are proportional to the blood volume.
Thus, the Left Ventricular cavity is enhanced, compared with the surrounding heart muscle (which has relatively lower myocardial blood volume).
With the advancement in ultrasound techniques and improved microbubble technology, it is now possible also to assess myocardial microcirculation and hence perfusion.
Contrast echocardiography provides the clinical efficacy and safety of ultrasound contrast agents and thus evidence-based recommendations and protocols for the use of contrast echocardiography is used in various clinical scenarios.
Clinical importance:
The clinical applications of contrast echocardiography have been expanded since the early days of contrast enhancement.
It is widely cited that contrast echocardiography can be used to identify Doppler signal enhancement, evaluation of non-compaction cardiomyopathy, thrombus detection, assessment of global and regional wall motion, and to enhance the endocardial border.
- Contrast echocardiography is performed for the assessment of regional and global left ventricular (LV) function both at rest and under stress for the optimal evaluation of LV structure and for the assessment of myocardial perfusion.
- Left ventricular (LV) opacification with contrast echocardiography has the potential to improve the definition of the LV border. The aim of contrast echocardiography is to provide better quantification of LV volume and assessment of LV wall motion analysis than echocardiography alone.
- Stress echocardiography is use for detection of regional wall motion abnormality for the diagnosis of coronary artery disease because in stress echocardiography (SE), the uptake is higher than in rest echocardiography
- Use of contrast in stress echocardiography is indicated to obtain diagnostic assessment of segmental wall motion and thickening at rest and stress, to increase the proportion of diagnosis studies and reader interpretation.
- Contrast echocardiography can be used for detection of right-to-left shunts, arterial septal defects,
- It may be used to enhance tricuspid Doppler signal for use in assessment of transvalvular velocity to estimate right ventricular systolic pressures
- The contrast agent transverse the pulmonary vasculature and are indicated for Left Ventricular opacification and Left Ventricular endocardial border definition in patients with technically suboptimal echocardiograms.
- Myocardial ischemia and infarction affecting myocardial perfusion and contractibility, it would be ideal to provide both simultaneously by myocardial contrast perfusion echocardiography.
- Contrast echocardiography can also be used in combination with color kinesis to show the degree of myocardial thickening.
- Three-dimensional echocardiography can provide quantitative method for measuring Left Ventricular volume and assessing wall motion with stress echocardiography.
- Myocardial contrast perfusion echocardiography has been an essential tool or performing alcohol ablation of septal coronary artery in patients with obstructive hypertrophic cardiomyopathy.
- Contrast echocardiography improves image quality through improve endocardial border definition during stress echocardiography. Contrast has been shown to improve visualization of regional wall motion abnormalities, improve study quality and increase reader confidence in study interpretation.
Contrast in Practice:
- SonoVue (Bracco, Milan) doesn’t need refrigeration. Just prepare and inject at room temperature.
- High echogenicity
- It gives homogeneous enhancement without artifacts or shadowing
- Allows to perform much accurate measurements, giving a higher diagnostic value to the exam.
- A small dose (1 ml) can opacity the ventricle for up to 2 minutes in real time, so by repeating the injections you can optimize the whole stress-echo exam in all its phases.
- Highly stable and persistent
- Safe
Contrast echocardiography over other modalities:
A contrast ultrasound exam is much easier and safer. It is repeatable, dynamic and the amount of added diagnostic information is immediately seen, allowing complete assessment of the patient’s condition during routine examinations.
What about during stress-echo?
- Immediate evaluation of wall motion abnormalities, EF and regional segments
- Less risky
- Avoids exposure to ionizing radiations.
- Echocardiography is the method of choice for repetitive cardiac Imaging.
- Contrast application can close the gap between MRI and echocardiography in those patients with suboptimal images.
- Even with the use of contrast, echocardiography remains a very cost-effective test that can be easily integrated into the workflow, either as an outpatient appointment or as treatment on the ward.
- Once we have the diagnostic information from contrast ultrasound, normally the patient doesn’t need to do more exams, unless there is need for a deeper assessment. But in any case, the contrast exam will always give enough info to make a diagnosis and follow-up.
- CEUS also reduces the time of the whole stress protocol.
- Contrast echocardiography is safe and have no side effects
Conclusion:
Contrast echocardiography utilizes the interaction of microscopic gas bubbles with ultrasound to enhance recognition of blood pool and tissues.
Improved contrast agent technology combined with the introduction of harmonic imaging has increased sensitivity of the technique and expanded the indications of contrast echocardiography.
Contrast enhanced echocardiography enhances the image quality during rest and stress echocardiography by many folds and provides an additional information on myocardial perfusion.
The addition of contrast to echocardiography improves the visualization of the heart in patients with previously uninterpretable or suboptimal echocardiography results.
Contrast echocardiography reduces the requirement for extra, expensive, and more risky tests and, importantly, saves the patient from further examinations.
Thus, contrast echocardiography provides a safe and comprehensive assessment of cardiac structure, perfusion, function, and coronary flow.
Recent developments in the technique of myocardial contrast echocardiography enables assessment of myocardial perfusion in both infarction and chronic heart disease during intravenous infusion of left heart contrast.
Quantification of myocardial blood flow by echocardiography is on the threshold of routine clinical use.
Visit the following link:
https://ceusconsulting.com to learn more about the contrast echocardiography and application specialist services.
References:
http://www.icus-society.org/wp-content/uploads/2018/08/Senior-Contrast-Echo-2017-EHJCVI.pdf