Multigate transcranial doppler ultrasound system with real-time embolic signal identification and archival

• Published in: IEEE transactions on ultrasonics, ferroelectrics, and frequency control ferroelectrics, and frequency control, 2006-10, Vol.53 (10), p.1853-1861
• Main Authors: Lingke Fan, Boni, E., Tortoli, P., Evans, D.H.
• Format: Article
• Language: English
• Subjects: Acoustics; Acquisitions; Adult; Algorithms; Artificial Intelligence; Automatic control; Biological and medical sciences; Channels; Computer Systems; Control systems; Doppler; Doppler effect; Echoencephalography - instrumentation; Echoencephalography - methods; Engines; Equipment Design; Equipment Failure Analysis; Exact sciences and technology; Fast Fourier transforms; Fourier transforms; Fundamental areas of phenomenology (including applications); General equipment and techniques; Hardware; Humans; Image Enhancement - instrumentation; Image Interpretation, Computer-Assisted - instrumentation; Information Storage and Retrieval - methods; Instruments, apparatus, components and techniques common to several branches of physics and astronomy; Intracranial Embolism - diagnostic imaging; Investigative techniques, diagnostic techniques (general aspects); Marketing; Medical sciences; Miscellaneous. Technology; Pattern Recognition, Automated - methods; Physics; Pilot Projects; Radiology Information Systems; Real time systems; Reasoning; Reproducibility of Results; Sensitivity and Specificity; Signal detection; Signal processing; Signal Processing, Computer-Assisted - instrumentation; Transducers; Ultrasonic imaging; Ultrasonic investigative techniques; Ultrasonics, quantum acoustics, and physical effects of sound; Ultrasonography, Doppler - instrumentation; Ultrasonography, Doppler - methods
• ISSN: 0885-3010; 1525-8955
• DOI: 10.1109/TUFFC.2006.117

An integrated system for acquisition and processing of intracranial and extracranial Doppler signals and automatic embolic signal detection has been developed. The hardware basis of the system is a purpose-built acquisition/processing board that includes a multigate Doppler unit controlled through a computer. The signal-processing engine of the system contains a fast Fourier transform (FFT)-based, spectral-analysis unit and an embolic signal-detection unit using expert system reasoning theory. The system is designed so that up to four receive gates from a single transducer can be used to provide useful reasoning information to the embolic signal-detection unit. Alternatively, two transducers can be used simultaneously, either for bilateral transcranial Doppler (TCD) investigations or for simultaneous intraand extracranial investigation of different arteries. The structure of the software will allow the future implementation of embolus detection algorithms that use the information from all four channels when a single transducer is used, or of independent embolus detection in two sets of two channels when two transducers are used. The user-friendly system has been tested in-vitro, and it has demonstrated a 93.6% sensitivity for micro-embolic signal (MES) identification. Preliminary in-vivo results also are encouraging