The present invention generally relates to medical devices, and more particularly to an improved medical imaging device. In one embodiment, an imaging device includes a drive shaft having proximal and distal ends received within the lumen an imaging transducer coupled to the distal end of the drive shaft and positioned at the distal portion of the elongate member and a flow detector coupled to the imaging transducer. The flow detector may include a forward facing ultrasound transducer configured to emit energy in the direction of the longitudinal axis of the imaging device and detect a Doppler shift in the received echoes. In the case where the imaging device is located in a vessel having blood flow, such information may be used to calculate the velocity of the blood flow. The imaging device may be configured to be located in a catheter or guidewire.
