Assessing Perforator Architecture

Methods of studying vascular anatomy

Flaps were harvested from fresh cadavers from the University of Texas Willed Body Program. Types of flaps included deep inferior epigastric artery perforator (DIEP), superior gluteal artery perforator flap (SGAP), and thoracodorsal artery perforator (TDAP) flaps. These were injected with contrast to determine the vascular territory in the zones of perfusion. All flaps were then submitted to static and dynamic computed tomography (CT) scan imaging.

Dynamic (Four-dimensional) CT Scanning

Dynamic or four-dimensional (4D) CT scanning refers to sequential images produced by repeated scanning as contrast flows through the flap. This technique results in a video of simulated flap perfusion. Single perforator injections were performed with iodinated contrast medium and the flap subjected to dynamic CT scanning using a GE Lightspeed 16-slice scanner (General Electric, Milwaukee, WI, USA). Scans were repeated at timed intervals, thus giving us progressive CT images over time. We found a total volume of 3 to 4 mL of contrast was sufficient for each flap injection.

Static (Three-dimensional) CT Scanning

A barium-gelatin mixture was injected into the investigated perforator to fill the vascular territory. Flaps were then frozen for at least 24 hours before CT scanning.

Three-dimensional (3D) and 4D images were viewed using the TeraRecon Aquarius workstation (version 3.2.2.21; TeraRecon, Inc, San Mateo, CA, USA). The volume-rendering function allowed us to produce clear and accurate images of the simulated flaps.

The perforasome, direct, and indirect linking vessels

Each cutaneous perforator has its own unique vascular arterial territory, which we described as being an arterial perforasome. Each perforasome is linked with adjacent perforasomes via 2 main mechanisms. These mechanisms include both direct and indirect linking vessels ( Fig. 1 ).