Criteria for identification of high-intensity transient signals
| Criteria |
|---|
| 1) Doppler microembolic signal is transient, usually lasting <300 ms |
| 2) The amplitude is usually at least 3 dB higher than the background blood flow |
| 3) A signal is unidirectional within the Doppler velocity spectrum |
| 4) Microembolic signal is accompanied by an audible output |