High frame rate cardiac ultrasound for visualizing small-scale heart muscle movement
Cardiac ultrasound is a fast, inexpensive, and non-invasive method for visualizing the structure and function of the heart and for diagnosing cardiovascular conditions such as a heart murmur or heart attack. There are over 31 million cardiac ultrasounds performed in the United States every year. As the heart pumps blood, there are smaller contractions that occur in different regions of the heart wall. Analyzing these regional contractions of the heart is crucial for the diagnosis and monitoring of coronary artery disease (18 million patients in the US) and cardiac arrhythmias (12 million patients in the US). However, ultrasound imaging of these propagating waves of contractions along the walls of the heart is difficult and subjective. Specifically, the movement of the heart as it pumps blood can make it difficult to detect these smaller contractions. Therefore, there is a need for an easily interpretable and objective method of visualizing small, propagating contractions in the wall of the heart while it is in motion.
Duke inventors have developed a new method of analyzing high frame rate cardiac ultrasounds to track and measure small movements in the wall of the heart while it is in motion. This method is capable of measuring the amplitude of motion, contractions, and relaxations of the heart muscle throughout the stages of the cardiac cycle. This is aided by a time reference provided by a simultaneous electrocardiogram recording, which measures the electrical activity of the heart. Specifically, the user is able to detect these small motions and see which regions of the tissue are moving at a high speed, a low speed, or are staying stationary using the difference in brightness of various regions between frames of the ultrasound video. This unique method produces extremely high timescale-resolution measurements of movements in the heart, which aids the diagnosis and monitoring of various cardiac conditions.
This method can also be used for measuring the stiffness of the walls of the heart, which has various applications in monitoring heart health, such as detecting cardiac fibrosis.
- High time and spatial resolution (300 images per second) of small contractions and relaxations in the cardiac muscle, which helps the diagnosis of coronary artery disease and cardiac arrythmias.
- Ultrasound imaging of the heart is safer and faster than MRI and CT imaging.
- Improved sensitivity of a low-cost, non-invasive cardiac imaging method.