title: Multimodality imaging approach for serial assessment of regional changes in lower extremity arteriogenesis and tissue perfusion in a porcine model of peripheral arterial disease.
abstract: BACKGROUND
  A standard quantitative imaging approach to evaluate peripheral arterial disease does not exist. Quantitative tools for evaluating arteriogenesis in vivo are not readily available, and the feasibility of monitoring serial regional changes in lower extremity perfusion has not been examined.
  
  
  RESULTS
  Serial changes in lower extremity arteriogenesis and muscle perfusion were evaluated after femoral artery occlusion in a porcine model using single photon emission tomography (SPECT)/CT imaging with postmortem validation of in vivo findings using gamma counting, postmortem imaging, and histological analysis. Hybrid 201Tl SPECT/CT imaging was performed in pigs (n=8) at baseline, immediately postocclusion, and at 1 and 4 weeks postocclusion. CT imaging was used to identify muscle regions of interest in the ischemic and nonischemic hindlimbs for quantification of regional changes in CT-defined arteriogenesis and quantification of 201Tl perfusion. Four weeks postocclusion, postmortem tissue 201Tl activity was measured by gamma counting, and immunohistochemistry was performed to assess capillary density. Relative 201Tl retention (ischemic/nonischemic) was reduced immediately postocclusion in distal and proximal muscles and remained lower in calf and gluteus muscles 4 weeks later. Analysis of CT angiography revealed collateralization at 4 weeks within proximal muscles (P<0.05). SPECT perfusion correlated with tissue gamma counting at 4 weeks (P=0.01). Increased capillary density was seen within the ischemic calf at 4 weeks (P=0.004).
  
  
  CONCLUSIONS
  201Tl SPECT/CT imaging permits serial, regional quantification of arteriogenesis and resting tissue perfusion after limb ischemia. This approach may be effective for detection of disease and monitoring therapy in peripheral arterial disease.
authors.affiliation: Departments of Internal Medicine, Biomedical Engineering, Surgery, and Diagnostic Radiology, Yale University School of Medicine, New Haven, CT.
authors.forename: Mitchel R
authors.initials: MR
authors.lastname: Stacy
authors.forename: Da Yu
authors.initials: DY
authors.lastname: Yu
authors.forename: Mark W
authors.initials: MW
authors.lastname: Maxfield
authors.forename: Irina M
authors.initials: IM
authors.lastname: Jaba
authors.forename: Bartosz P
authors.initials: BP
authors.lastname: Jozwik
authors.forename: Zhen W
authors.initials: ZW
authors.lastname: Zhuang
authors.forename: Ben A
authors.initials: BA
authors.lastname: Lin
authors.forename: Christi L
authors.initials: CL
authors.lastname: Hawley
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Caracciolo
authors.forename: Prasanta
authors.initials: P
authors.lastname: Pal
authors.forename: Daniela
authors.initials: D
authors.lastname: Tirziu
authors.forename: Smita
authors.initials: S
authors.lastname: Sampath
authors.forename: Albert J
authors.initials: AJ
authors.lastname: Sinusas
mesh_terms: D000818:Animals; D001158:Arteries / Q000000981:diagnostic imaging / Q000503:physiopathology; D002196:Capillaries / Q000000981:diagnostic imaging / Q000503:physiopathology; D003097:Collateral Circulation; D004195:Disease Models, Animal; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D064847:Multimodal Imaging / Q000379:methods*; D018919:Neovascularization, Physiologic; D055420:Perfusion Imaging; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D013552:Swine; D015899:Tomography, Emission-Computed, Single-Photon; D014057:Tomography, X-Ray Computed
keywords: emission-computed; perfusion; peripheral arterial disease; single-photon; tomography