Abstract: A programmable probe multiplexer which can be reconfigured for use with multiple imaging systems having different channel counts. The probe uses a system code that informs the multiplexer of the number of channels on the system to which it is connected. The multiplexer hardware in turn adjusts the program or channel map to reconfigure the probe to accommodate the system. In particular, the probe can sense the presence of a system type and then reconfigure and optimize performance automatically, or the probe can be reprogrammed by the system, allowing great flexibility in the design and optimization of imaging parameters. The probe supports this concept through the use of a series of programmable switches and the appropriate logic to assign input channels to output channels.

Abstract: This disclosure relates to a noninvasive means for detecting, counting and characterizing emboli moving through the arterial or venous circulation. An ultrasonic transducer is applied to the skin or other tissues of the subject at sites such as over the temporal bone on either side of the head of the subject, on the neck, on the chest, the abdomen, arm, leg, within the esophagus, or surgically exposed organs or blood vessels. Using standard ultrasonic Doppler techniques, Doppler-shifted signals are located which are proportional to the blood flow velocity in the blood vessel(s) of interest. Spectral analysis is performed on the received signal using the fast Fourier transform or other appropriate technique to determine the frequency components in the Doppler shift spectrum. Further analysis of the spectra is used to delineate and characterize Doppler shift signals due to blood from Doppler shift signals due to emboli having a variety of compositions.