The Role of Contrast in Echocardiography
Stephanie N. Johnson
Majesh Makan
Key Points for Contrast Optimization
Mechanical index (MI) <0.5
Optimize time gain compensation and overall gain settings
Minimize near-field gain
Generally have focus point at the base of the heart
Optimize probe position for non-foreshortened views
Doppler enhancement measuring the modal/darkest envelope
Correct timing and dose of contrast requires good communication between sonographer and nurse
Indications
Reduced image quality with ≥2 wall segments not visualized
Increase the accuracy of ventricular volume measurement
Stress testing for enhanced endocardial edge detection
Doppler signal enhancement
Evaluation for LV thrombus, LV aneurysm
Intracardiac masses
Contraindications
Pregnant or lactating women
Patients who have known allergic reaction to Perflutren (Octafluropropane gas)
Right-to-left, bi-directional or transient right-to-left cardiac shunts
Sensitivity to blood, blood products, or albumin (Optison™ only)
General Principles
Using contrast while performing an echocardiogram can play a vital role and provide additional information in the patient’s diagnosis and management. Contrast consists of microbubbles that when mixed with red blood cells in the cardiac chambers increase the scatter of the ultrasonic signal, therefore enhancing the blood–tissue
interface. Optison™ is a Perfluoropropane-filled shell derived from human serum albumin, whereas Definity™ is a Perfluoropropane lipid–coated microbubble that has to be agitated before use. The FDA has approved contrast for left ventricular (LV) opacification and enhancement of endocardial border definition.
interface. Optison™ is a Perfluoropropane-filled shell derived from human serum albumin, whereas Definity™ is a Perfluoropropane lipid–coated microbubble that has to be agitated before use. The FDA has approved contrast for left ventricular (LV) opacification and enhancement of endocardial border definition.
Contrast Should be Given to Patient When:
Reduced image quality: Two or more wall segments cannot be visualized in any one view.
Doppler signal enhancement
For valvular stenosis and regurgitation
The best Doppler signal is obtained at the beginning of contrast administration. This helps avoid “blooming” artifact and overestimation of the Doppler signal
Measure only the modal envelope (Fig. 3-1)
Rule out LV apical pathology: LV thrombus, aneurysm, pseudoaneurysm, apical hypertrophy, non-compaction (Fig. 3-2)
Assess regional wall motion abnormalities
Exercise/pharmologic stress testing
Ensures visualization of all myocardial segments
Increase accuracy of ejection fraction and LV volume calculations (Fig. 3-3)
ICU and ER settings
ICU patients are usually technically difficult to image due to mechanical ventilation, chest tubes, bandages, presence of lung disease, and inability for patients to be repositioned.
Most patients are imaged supine rather than in the left lateral position.
Using contrast in the ER is helpful when patients come in with chest pain to provide complete analysis of all myocardial segments for regional wall motion abnormalities.
Identifying intracardiac masses
Thrombus does not enhance and is outlined as a “black” mass with contrast enhancement of the cardiac chambers.
Tumors within the cardiac chambers can similarly be outlined by contrast.
The use of contrast increases the sensitivity of detection of intracardiac masses and also helps in differentiating these from normal structures (e.g., LV trabeculation) (Fig. 3-4).
Key Point:
Move focus point transiently from the base of the heart to the apex to evaluate the LV apex for pathology.
Key Point:
Even though IV contrast may help with endocardial definition it does not reduce image foreshortening secondary to non-optimal probe or patient positioning. Try to optimize the image prior to contrast administration.
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