title: Simplified contrast ultrasound accurately reveals muscle perfusion deficits and reflects collateralization in PAD.
abstract: BACKGROUND
  Simplified contrast-enhanced ultrasound (CEUS) can be used to evaluate muscle perfusion in peripheral arterial disease (PAD). Here, we report its diagnostic accuracy for detecting symptomatic PAD. Additionally, we hypothesize that the extent of collateral formation is reflected by CEUS.
  
  
  METHODS
  Ultrasound contrast agent was injected into an antecubital vein of 58 control subjects and 52 symptomatic PAD patients and its appearance in the calf muscle was evaluated. Interreader variability was tested using 118 raw data films. Arterial collateralization of PAD patients was assessed by angiographic imaging.
  
  
  RESULTS
  PAD patients showed a significantly longer median time to peak intensity (TTP, 36.9s) than control subjects (19.4s, p<0.001) with longer TTPs in advanced PAD stages. The area under the receiver operating characteristic curve was 0.942 and the mean TTP difference between two blinded readers was 0.28s. A TTP cut off at 30.5s was associated with 91% positive predictive value. PAD patients with good collateralization showed a significantly shorter TTP (34.1s) than patients with poor collateralization (44.0 s, p=0.008) but not a higher ankle-brachial index (ABI).
  
  
  CONCLUSIONS
  CEUS accurately displays perfusion deficits of the calf muscle in symptomatic PAD patients. The degree of arterial collateralization is reflected by CEUS and not by ABI.
authors.affiliation: Department of Cardiology and Angiology, University Hospital of Freiburg, Hugstetter Street 55, 79106 Freiburg, Germany. danieldue@gmx.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Duerschmied
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhou
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Rink
authors.forename: Dorothee
authors.initials: D
authors.lastname: Harder
authors.forename: Gabriele
authors.initials: G
authors.lastname: Freund
authors.forename: Manfred
authors.initials: M
authors.lastname: Olschewski
authors.forename: Christoph
authors.initials: C
authors.lastname: Bode
authors.forename: Christoph
authors.initials: C
authors.lastname: Hehrlein
mesh_terms: D000368:Aged; D003097:Collateral Circulation; D003935:Diagnostic Techniques, Cardiovascular / Q000592:standards; D005260:Female; D006801:Humans; D007511:Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply*; D016491:Peripheral Vascular Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015203:Reproducibility of Results; D014463:Ultrasonography / Q000379:methods* / Q000592:standards*