Laparoscopic Intraoperative Ultrasonography, Color Doppler, and Power Flow Application

The applications of color Doppler and power flow imaging for laparoscopic intraoperative ultrasonography (LIOU) are discussed. Basic principles concerning Doppler, color Doppler imaging (CDI), and power flow (PF) are briefly reviewed, and a number of representative examples of imaging are provided. LIOU is progressively gaining importance, not only for screening of the biliary tract, but in particular, for staging laparoscopy in patients with gastrointestinal cancer. The CDI technology that was developed relatively quickly is now in widespread use in diagnostic ultrasound, particularly for vascular surgery. CD options are no longer restricted to the expensive high-end ultrasound scanners, but are available in the majority of modest duplex systems with limited additional costs. Ongoing developments in ultrasound technology have resulted in the introduction of an alternative option to mean frequency-based CD ultrasound, ie, the PF. There are several advantages that emanate from the combination of B-mode ultrasound with CDI and/or PF. These include (1) rapid identification of anatomical structures, ie, vessels, ducts, tissue spaces, and cysts; (2) detection of small vessels that are difficult or impossible to recognize by B-mode scanning alone; (3) more accurate assessment of vascular encasement/involvement by tumor and a precise display of major vessels anatomically related to the tumor; (4) real-time guidance for safe parenchymal dissection of solid organs with identification and preservation of blood supply; (5) precise guided needle biopsy or puncture; and (6) visualization of bile flow in common bile by PF. This has the potential to enable dynamic flow studies of the function of the papilla of Vater in the near future.