 | | |
|
Contrast microbubbles can be destroyed by intense ultrasound and the scattered signal level can increase abruptly for a short time during microbubble destruction, resulting in an acoustical flash (sudden increase in echogenicity).
Intermittent imaging with high acoustic output utilizes the properties of contrast microbubbles to improve blood-to-tissue image contrast by imaging intermittently at very low frame rates.
The frame rate is usually reduced to about one frame per second, or it is synchronized with cardiac cycles so that enough contrast microbubbles can flow into the imaging site where most microbubbles have been destroyed by the previous acoustic pulse. Because bubbles are destroyed by ultrasound, controlling the delay time between frames produces images whose contrast emphasizes regions with rapid blood flow rate or regions with high or low blood volume.
|
| |
 |
|
| |
| | |