title: Skin perfusion assessed by contrast ultrasound predicts tissue survival in a free flap model.
abstract: The purpose of this study was to assess perfusion in a free skin flap model using contrast-enhanced ultrasound (CEU), and to determine if the extent of perfusion early after venous occlusion predicted long-term flap survival. Perfusion was assessed in an autologous abdominal skin flap and adjacent healthy skin in rats using CEU imaging before venous occlusion and following reflow. Perfusion assessment was possible in all flaps and quantitative measurements of microvascular blood volume (BV) and blood velocity were expressed as a ratio to that in the healthy skin. Proximal flap BV 18 h after venous occlusion was significantly greater in those that survived (n = 4) vs. those that became necrotic (n = 6) (BV ratio 0.8 +/- 0.1 vs. 0.2 +/- 0.1, p = 0.0001). A BV ratio of 0.5 predicted graft viability with a sensitivity and specificity of 100%. Microvascular blood velocity at 18 h was similar in grafts that survived and those that became necrotic. Qualitative assessment of perfusion by a "blinded" observer correlated well with quantitative data and predicted flap outcome in all cases. We conclude that skin perfusion can be assessed with CEU. Perfusion 18 h following a secondary ischemic insult in a free flap accurately predicts subsequent tissue survival in this model.
authors.affiliation: Cardiac Imaging Center, the Cardiovascular Division, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Christiansen
authors.forename: Howard
authors.initials: H
authors.lastname: Leong-Poi
authors.forename: Lester R
authors.initials: LR
authors.lastname: Amiss
authors.forename: David B
authors.initials: DB
authors.lastname: Drake
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Kaul
authors.forename: Jonathan R
authors.initials: JR
authors.lastname: Lindner
mesh_terms: D000005:Abdomen / Q000000981:diagnostic imaging; D000818:Animals; D001810:Blood Volume / Q000502:physiology; D003287:Contrast Media; D004195:Disease Models, Animal; D006083:Graft Occlusion, Vascular / Q000000981:diagnostic imaging; D008297:Male; D009336:Necrosis; D051381:Rats; D017207:Rats, Sprague-Dawley; D012867:Skin / Q000098:blood supply* / Q000000981:diagnostic imaging*; D013524:Surgical Flaps / Q000098:blood supply* / Q000473:pathology*; D013997:Time Factors; D014022:Tissue Survival / Q000502:physiology*; D014463:Ultrasonography
chemical_list: D003287:Contrast Media