ABSTRACT
OBJECTIVE: Advancements in technology have improved image acquisition and processing in the field of medical imaging, giving medical doctors the tools to implement effective medical care. In plastic surgery, despite advances in anatomical knowledge and technology, problems in preoperative planning for flap surgery remain. METHODS: In this study, we propose a new protocol to analyze three-dimensional (3D) Photoacoustic tomography images and generate two-dimensional (2D) mapping sheets that can help surgeons identify perforators and the perfusion territory during preoperative planning. The core of this protocol is PreFlap, a new algorithm that converts 3D photoacoustic tomography images into 2D vascular mapping images. CONCLUSION: Experimental results demonstrate that PreFlap can improve preoperative flap evaluation, thus can greatly saving surgeons' time and improving surgical outcomes.
Subject(s)
Plastic Surgery Procedures , Tomography, X-Ray Computed , Humans , Tomography, X-Ray Computed/methods , Imaging, Three-Dimensional/methods , Preoperative Care/methods , AlgorithmsABSTRACT
BACKGROUND: Photoacoustic tomography is a noninvasive vascular imaging modality that uses near-infrared pulsed laser light and ultrasound to visualize vessels. We previously demonstrated the utility of photoacoustic tomography for anterolateral thigh flap surgery involving body-attachable vascular mapping sheets. However, it was not possible to obtain clear separate images of arteries and veins. In this study, we tried to visualize subcutaneous arteries that cross the midline of the abdomen, since these arteries are known to be important for obtaining large perfusion areas in transverse abdominal flaps. METHODS: Four patients scheduled to undergo breast reconstruction with abdominal flaps were examined. Photoacoustic tomography was performed preoperatively. The tentative arteries and veins were traced according to the S-factor, an approximate hemoglobin oxygen saturation parameter calculated using 2 laser excitation wavelengths (756 and 797 nm). Intraoperatively, arterial-phase indocyanine green (ICG) angiography was performed after abdominal flap elevation. Images of vessels speculated to be arteries by preoperative photoacoustic tomography were merged with those of intraoperative ICG angiography and analyzed in an 8 × 4-cm2 area below the umbilical region. RESULTS: The S-factor was used to visualize the midline-crossing subcutaneous arteries in all 4 patients. A matching analysis compared preoperative tentative arteries according to photoacoustic tomography with ICG angiography results in the 8 × 4-cm2 area below the umbilical region and indicated a 71.3-82.1% match (average: 76.9% match). CONCLUSIONS: This study demonstrates that the S-factor, a noninvasive, label-free imaging modality, can be used to successfully visualize subcutaneous arteries. This information can aid in selecting perforators for abdominal flap surgery.
