©Walter Rasmussen, R.D.C.S.
The most common site for a thrombus is at the left ventricular apex and is best detected from all of the apical views. The sonographer should always be alert for and investigate anything at the apex that has similar appearance to a thrombus. The presence of apical thinning and scaring, a wide left ventricular apex and/or hypokinesis to dyskinesis and aneurysm should cause the sonographer to give the area special attention for the presence of an apical thrombus.
Any or all of the following adjustments will help maximize sensitivity and resolution of the ultrasound machine:
- Decrease the depth or use the zoom so that the apical region is featured.
- Move the focus to the level of the apex.
- Use the highest frequency that has sufficient penetration and contrast.
- Use 2-D Colorization to aid in visualization.
- Ask the physician to authorize the us of LV contrast for more definitive assessment and diagnosis.
A suspected left ventricular thrombus needs to be distinguished from normal endocardial trabeculations which are often seen at the left ventricular apex. Trabeculations can be distinguished from a thrombus by demonstrating their anatomical relationship to the left ventricular wall with a long digital clip, showing a seamless connection to the myocardium and that it thickens during systole. Thrombi will usually have a different textural appearance from the myocardial tissue and are usually more spherical in shape, or if of the laminated type, will appear as an akinetic segment, distinct and motionless against the left ventricular wall.
The administration of left ventricular contrast can be very helpful in distinguishing a thrombus from myocardial tissue. As the contrast fills the left ventricular chamber, a thrombus will appear darker than the surrounding tissue.