title: Correlation of contrast-enhanced power Doppler sonography and conventional angiography of abduction-induced hip ischemia in piglets.
abstract: OBJECTIVE
  The purpose of this study was to determine if enhanced power Doppler sonography can detect early ischemia of the capital femoral epiphysis induced by hip hyperabduction in piglets and to correlate these findings with angiography.
  
  
  METHODS
  Proximal femoral perfusion was evaluated in 18 studies of 10 piglet hips with unenhanced power Doppler sonography, enhanced power Doppler sonography with IV contrast agent, and digital angiography, in neutral position, hyperabduction, and after release to neutral position. Enhancement ratios between pixel intensities of power Doppler sonography and enhanced power Doppler images in each position were calculated. Angiograms were analyzed for differences in flow with changes in hip position.
  
  
  RESULTS
  With the piglet in neutral position, power Doppler sonography revealed few vessels in the femoral head. Contrast administration resulted in a temporary marked increase in the visualization of vessels in the femoral head. Quantitative enhanced power Doppler sonography revealed a marked decrease in pixel intensity with abduction (p < 0.001) that was not apparent on unenhanced studies (p = 0.28). The enhancement ratio decreased from 0.45 (mean +/- SD, +/- 0.26) in neutral position to 0.10 (+/- 0.21) after abduction; it returned to 0.41 (+/- 0.14) after release of abduction (p < 0.001 for each comparison). Angiographic studies in hyperabduction revealed a variable level of ischemia.
  
  
  CONCLUSIONS
  Enhanced power Doppler sonography can be used to visualize the vascular supply to the cartilaginous femoral head in piglets and can detect reversible ischemia induced by hip hyperabduction. These differences correlate with digital angiographic evidence of ischemia.
authors.affiliation: Department of Radiology, Children's Hospital, 300 Longwood Ave., Boston, MA 02115, USA.
authors.forename: Carol E
authors.initials: CE
authors.lastname: Barnewolt
authors.forename: Diego
authors.initials: D
authors.lastname: Jaramillo
authors.forename: George A
authors.initials: GA
authors.lastname: Taylor
authors.forename: Patricia S
authors.initials: PS
authors.lastname: Dunning
mesh_terms: D000792:Angiography; D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D004838:Epiphyses / Q000098:blood supply / Q000000981:diagnostic imaging; D005240:Feasibility Studies; D005270:Femur Head / Q000098:blood supply / Q000000981:diagnostic imaging*; D006617:Hip Dislocation / Q000150:complications / Q000000981:diagnostic imaging*; D007511:Ischemia / Q000000981:diagnostic imaging* / Q000209:etiology; D012039:Regional Blood Flow; D013552:Swine; D018608:Ultrasonography, Doppler
chemical_list: D003287:Contrast Media