Quantification of In Vivo Kinematics of Superficial Femoral Artery due to Hip and Knee Flexion Using Magnetic Resonance Imaging
Christopher P. Cheng
The objective of this study is to quantify the in vivo kinematics of the superficial femoral artery (SFA) caused by hip and knee flexion by utilizing vascular and skeletal magnetic resonance (MR) imaging and image processing methods. Seven male healthy volunteers (56 ± 5 years old) were imaged using contrast-enhanced MR angiography in the supine and bent-leg positions using a GE Signa Excite 1.5-T scanner. Coregistered SFA coordinates from these two body positions provide the relative motion of the SFA with respect to the femur as a result of hip and knee flexion. With 86 ± 6° hip and 39 ± 6° knee flexion angles, the proximal portion of the SFA moved significantly inferiorly while the distal portion of the SFA stayed immobile in relation to the femur due to hip and knee flexion. From the supine position to the bent-leg position, the top of the SFA moved 23.5 ± 7.0 mm closer to the bottom of the SFA (p < 0.05), resulting in shortening and buckling of the SFA. The differential translations of points along the SFA indicate shortening and buckling along the length of the vessel. They also indicate that the SFA is more tethered to the bony structures at the knee compared to the thigh. The in vivo SFA kinematics obtained in this study provides insight into the interaction between the SFA and the surrounding musculoskeletal structures.