title: Blood Oxygenation Level-Dependent CMR-Derived Measures in Critical Limb Ischemia and Changes With Revascularization.
abstract: BACKGROUND
  Use of blood oxygenation level-dependent cardiovascular magnetic resonance (BOLD-CMR) to assess perfusion in the lower limb has been hampered by poor reproducibility and a failure to reliably detect post-revascularization improvements in patients with critical limb ischemia (CLI).
  
  
  OBJECTIVE
  This study sought to develop BOLD-CMR as an objective, reliable clinical tool for measuring calf muscle perfusion in patients with CLI.
  
  
  METHODS
  The calf was imaged at 3-T in young healthy control subjects (n = 12), age-matched control subjects (n = 10), and patients with CLI (n = 34). Signal intensity time curves were generated for each muscle group and curve parameters, including signal reduction during ischemia (SRi) and gradient during reactive hyperemia (Grad). BOLD-CMR was used to assess changes in perfusion following revascularization in 12 CLI patients. Muscle biopsies (n = 28), obtained at the level of BOLD-CMR measurement and from healthy proximal muscle of patients undergoing lower limb amputation (n = 3), were analyzed for capillary-fiber ratio.
  
  
  RESULTS
  There was good interuser and interscan reproducibility for Grad and SRi (all p < 0.0001). The ischemic limb had lower Grad and SRi compared with the contralateral asymptomatic limb, age-matched control subjects, and young control subjects (p < 0.001 for all comparisons). Successful revascularization resulted in improvement in Grad (p < 0.0001) and SRi (p < 0.0005). There was a significant correlation between capillary-fiber ratio (p < 0.01) in muscle biopsies from amputated limbs and Grad measured pre-operatively at the corresponding level.
  
  
  CONCLUSIONS
  BOLD-CMR showed promise as a reliable tool for assessing perfusion in the lower limb musculature and merits further investigation in a clinical trial.
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Adnan
authors.initials: A
authors.lastname: Bajwa
authors.affiliation: Department of Cardiovascular Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, BHF Centre of Research Excellence, Wellcome Trust-EPSRC Medical Engineering Centre & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Roman
authors.initials: R
authors.lastname: Wesolowski
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Ashish
authors.initials: A
authors.lastname: Patel
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Prakash
authors.initials: P
authors.lastname: Saha
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Francesca
authors.initials: F
authors.lastname: Ludwinski
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Ikram
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Mostafa
authors.initials: M
authors.lastname: Albayati
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom.
authors.forename: Alberto
authors.initials: A
authors.lastname: Smith
authors.affiliation: Department of Cardiovascular Imaging, Division of Imaging Sciences and Biomedical Engineering, King's College London, BHF Centre of Research Excellence, Wellcome Trust-EPSRC Medical Engineering Centre & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom; Institute for Experimental and Translational Cardiovascular Imaging, DZHK Centre for Cardiovascular Imaging, University Hospital Frankfurt, Goethe University Frankfurt, Frankfurt am Main, Germany.
authors.forename: Eike
authors.initials: E
authors.lastname: Nagel
authors.affiliation: Academic Department of Vascular Surgery, Cardiovascular Division, King's College London, BHF Centre of Research Excellence & NIHR Biomedical Research Centre at King's Health Partners, St. Thomas' Hospital, London, United Kingdom. Electronic address: bijan.modarai@kcl.ac.uk.
authors.forename: Bijan
authors.initials: B
authors.lastname: Modarai
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017130:Angioplasty / Q000379:methods*; D001706:Biopsy; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007511:Ischemia / Q000097:blood* / Q000175:diagnosis / Q000628:therapy; D007866:Leg / Q000098:blood supply*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism / Q000473:pathology; D010100:Oxygen / Q000097:blood*; D011379:Prognosis; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D018616:Ultrasonography, Doppler, Duplex; D055815:Young Adult
chemical_list: D010100:Oxygen
keywords: angioplasty; cardiovascular magnetic resonance; perfusion; surgery
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