Abstract: A small, disposable device for use in intraoperative diagnostic imaging in the form of a finger-mounted probe having an elongated chamber along its longitudinal midline for removably receiving the distal end of an ultrasonic imaging catheter equipped with an ultrasound generator having an imaging plane normal to the probe's longitudinal midline. The probe includes a body formed of relatively rigid non-echogenic material with an upper surface of concave cross-sectional contour shaped and dimensioned to receive the underside of a user's finger and also includes an integral retention band that bridges the body and extends over the tip portion of a user's finger when the probe is worn. A Doppler generator/detector may be mounted in the distal end wall of the probe for directing, detecting, and transmitting signals representative of blood flow velocity through a vessel contacted by the smooth undersurface of the probe along the imaging plane of the ultrasonic imaging catheter extending into the probe's chamber.