ABSTRACT
Overlaying laparoscopic ultrasound (LUS) images on live video is a preferable way to enhance intraoperative visualization during laparoscopic procedures. To achieve this, a real-time tracking method is needed to track the pose of the LUS probe relative to the pose of the laparoscopic camera. Common tracking methods are optical tracking, electromagnetic (EM) tracking, computer vision-based tracking, and hybrid tracking (i.e., a combination of these methods). Each method has their advantages and limitations. Many LUS-based laparoscopic AR (LUS-AR for short) systems have been developed in the past decade. Most of them were validated using phantoms or ex vivo tissues in a laboratory or an OR. A few studies were validated in live animals, mostly porcine models, and even fewer have presented human data. In this chapter, clinically promising LUS-AR systems in each tracking category are briefly reviewed, with a focus on optical and EM tracking-based systems. In addition, fast calibration methods for forward- and oblique-viewing laparoscopes are presented. These methods are a prerequisite for extending AR methods to conventional laparoscopes. The chapter concludes with the description of an ideal LUS-AR system that can be used clinically in the near future.
