Catheter mounted Doppler ultrasound transducers

A transducer was designed and fabricated for assessment of cochlear blood flow using 12.5 MHz microvascular Doppler ultrasonography. The design includes a 2-2 composite element, front acoustic matching layers, a rear "unmatching" layer, electrical tuning, and a 0.5 mm diameter brass core. Tests indicate low insertion loss, performance comparable to model predictions, and effective detection of cochlear blood flow.