Volume 6, Issue 4 (April 2009)
Feasibility of a Method to Quantify Movement-Induced Conformational Changes in the Superficial Femoral and Popliteal (Femoropopliteal) Arterial Tree Using 3-D Angiography
Endovascular revascularization of the superficial femoral and popliteal (femoropopliteal (FP)) artery is currently plagued by high rates of restenosis and stent fracture. One hypothesis behind these suboptimal clinical results implicates the unique physical forces that are applied to the FP segment during daily leg movement. In an effort to elucidate these forces, we applied angiography-based previously validated three-dimensional (3-D) modeling algorithms to angiograms of a FP artery in a patient with peripheral arterial disease. As the FP is the longest artery in the body, overlapping paired angiographic images of the entire FP artery were required. From these pair of two-dimensional angiographic views, individual 3-D FP segments can be generated. A validated fusion process was then performed in order to join these FP segments to form a complete 3-D FP artery. In order to investigate the effects of motion upon this arterial segment, we performed angiography and subsequent 3-D modeling of the FP artery in both the straight-leg (SL) and crossed-leg (CL) positions. In this paper, the methodology used to generate an in vivo FP artery model from sequentially acquired multiple angiographic images is reviewed. The data set from one patient in the SL and CL positions are used to demonstrate the 3-D modeling and fusion processes followed by the computation of various quantitative estimates in order to demonstrate the feasibility of this method. Inclusive in this technique is an assessment of the twist angle that is induced when the FP artery is moved from the SL to the CL position. The authors also submit the validation results for the method of calculating these twist angles as assessed on a metallic phantom and a computer-simulated arterial tree model.