A needle assembly for an ultrasound imaging system includes a needle having a proximal end and a distal end. The distal end is adapted to be inserted into a patient. The needle assembly also includes an optical sensor assembly secured to the distal end of the needle. The optical sensor assembly has a field of vision that includes the distal end of the needle and an environment surrounding the distal end of the needle as the needle is inserted into the patient towards a target site. In addition, the needle assembly includes a controller communicatively coupled to the optical sensor assembly. Thus, the controller is configured to receive and process one or more sensor signals from the optical sensor assembly in real-time.