Medical devices, apparatus, and instruments for use in the field of medical imaging, namely, medical needles; medical needle acoustic sensors; injection, biopsy or aspiration needles; acoustic sensors for injection, biopsy or aspiration needles; modules for visualizing acoustic sensor position; modules for visualizing the patient anatomy; modules for determining the position of acoustic sensors in relation to the patient anatomy; modules for a tracking position of needle during a diagnostic, therapeutic or surgical procedure; a needle tracking feature of an ultrasound system comprised of a probe, software for use therefor, a needle acoustic sensor for receiving acoustic probe signals and interfacing with the software and a display for visualizing patient anatomy and needle tracking