title: Quantification of popliteal artery deformation during leg flexion in subjects with peripheral artery disease: a pilot study.
abstract: OBJECTIVE
  To quantify the in vivo deformations of the popliteal artery during leg flexion in subjects with clinically relevant peripheral artery disease (PAD).
  
  
  METHODS
  Five patients (4 men; mean age 69 years, range 56-79) with varying calcification levels of the popliteal artery undergoing endovascular revascularization underwent 3-dimensional (3D) rotational angiography. Image acquisition was performed with the leg straight and with a flexion of 70°/20° in the knee/hip joints. The arterial centerline and the corresponding branches in both positions were segmented to create 3D reconstructions of the arterial trees. Axial deformation, twisting, and curvatures were quantified. Furthermore, the relationships between the calcification levels and the deformations were investigated.
  
  
  RESULTS
  An average shortening of 5.9%±2.5% and twist rate of 3.8±2.2°/cm in the popliteal artery were observed. Maximal curvatures in the straight and flexed positions were 0.12±0.04 cm(-1) and 0.24±0.09 cm(-1), respectively. As the severity of calcification increased, the maximal curvature in the straight position increased from 0.08 to 0.17 cm(-1), while an increase from 0.17 to 0.39 cm(-1) was observed for the flexed position. Axial elongations and arterial twisting were not affected by the calcification levels.
  
  
  CONCLUSIONS
  The popliteal artery of patients with symptomatic PAD is exposed to significant deformations during flexion of the knee joint. The severity of calcification directly affects curvature, but not arterial length or twisting angles. This pilot study also showed the ability of rotational angiography to quantify the 3D deformations of the popliteal artery in patients with various levels of calcification.
authors: 1 Institute for Surgical Technology & Biomechanics, University of Bern, Switzerland.
authors: Can
authors: C
authors: Gökgöl
authors: Nicolas
authors: N
authors: Diehm
authors: Levent
authors: L
authors: Kara
authors: Philippe
authors: P
authors: Büchler
mesh_terms: D000368:Aged; D057510:Endovascular Procedures / Q000295:instrumentation; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*; D056888:Patient Positioning; D058729:Peripheral Arterial Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy; D010865:Pilot Projects; D011150:Popliteal Artery / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011857:Radiographic Image Interpretation, Computer-Assisted; D012720:Severity of Illness Index; D015607:Stents; D061205:Vascular Calcification / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy