title: Arterial spin labeling perfusion cardiovascular magnetic resonance of the calf in peripheral arterial disease: cuff occlusion hyperemia vs exercise.
abstract: BACKGROUND
  Assessment of calf muscle perfusion requires a physiological challenge. Exercise and cuff-occlusion hyperemia are commonly used methods, but it has been unclear if one is superior to the other. We hypothesized that post-occlusion calf muscle perfusion (Cuff) with pulsed arterial spin labeling (PASL) cardiovascular magnetic resonance (CMR) at 3 Tesla (T) would yield greater perfusion and improved reproducibility compared to exercise hyperemia in studies of peripheral arterial disease (PAD).
  
  
  METHODS
  Exercise and Cuff cohorts were independently recruited. PAD patients had an ankle brachial index (ABI) between 0.4-0.9. Controls (NL) had no risk factors and ABI 0.9-1.4. Subjects exercised until exhaustion (15 NL-Ex, 15 PAD-Ex) or had a thigh cuff inflated for 5 minutes (12 NL-Cuff, 11 PAD-Cuff). Peak exercise and average cuff (Cuff mean ) perfusion were compared. Six participants underwent both cuff and exercise testing. Reproducibility was tested in 8 Cuff subjects (5 NL, 3 PAD).
  
  
  RESULTS
  Controls had greater perfusion than PAD independent of stressor (NL-Ex 74 ± 21 vs. PAD-Ex 43 ± 10, p = 0.01; NL-Cuff mean 109 ± 39 vs. PAD-Cuff mean 34 ± 17 ml/min-100 g, p < 0.001). However, there was no difference between exercise and Cuff mean perfusion within groups (p > 0.6). Results were similar when the same subjects had the 2 stressors performed. Cuff mean had superior reproducibility (Cuff mean ICC 0.98 vs. Exercise ICC 0.87) and area under the receiver operating characteristic curve (Cuff mean 0.992 vs. Exercise 0.905).
  
  
  CONCLUSIONS
  Cuff hyperemia differentiates PAD patients from controls, as does exercise stress. Cuff mean and exercise calf perfusion values are similar. Cuff occlusion hyperemia has superior reproducibility and thus may be the preferred stressor.
authors.affiliation: Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA. drdaviddlopez@gmail.com.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. drdaviddlopez@gmail.com.
authors.forename: David
authors.initials: D
authors.lastname: Lopez
authors.affiliation: Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA. amymarisapollak@gmail.com.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. amymarisapollak@gmail.com.
authors.forename: Amy W
authors.initials: AW
authors.lastname: Pollak
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. cmeyer@virginia.edu.|Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, VA, USA. cmeyer@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. cmeyer@virginia.edu.
authors.forename: Craig H
authors.initials: CH
authors.lastname: Meyer
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. fhe6b@virginia.edu.|Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, VA, USA. fhe6b@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. fhe6b@virginia.edu.
authors.forename: Frederick H
authors.initials: FH
authors.lastname: Epstein
authors.affiliation: Department of Biomedical Engineering, University of Virginia Health System, Charlottesville, VA, USA. lz5bf@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. lz5bf@virginia.edu.
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA. ajp8x@virginia.edu.|Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. ajp8x@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. ajp8x@virginia.edu.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Pesch
authors.affiliation: Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA. RJiji@billingsclinic.org.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. RJiji@billingsclinic.org.
authors.forename: Ronny
authors.initials: R
authors.lastname: Jiji
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. jrh2g@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. jrh2g@virginia.edu.
authors.forename: Jennifer R
authors.initials: JR
authors.lastname: Kay
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. jmd8c@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. jmd8c@virginia.edu.
authors.forename: Joseph M
authors.initials: JM
authors.lastname: DiMaria
authors.affiliation: Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. jmc2v@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. jmc2v@virginia.edu.
authors.forename: John M
authors.initials: JM
authors.lastname: Christopher
authors.affiliation: Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA. ckramer@virginia.edu.|Department of Radiology and Medical Imaging, University of Virginia Health System, Charlottesville, VA, USA. ckramer@virginia.edu.|Cardiovascular Imaging Center, University of Virginia Health System, Charlottesville, VA, USA. ckramer@virginia.edu.
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Kramer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D055109:Ankle Brachial Index; D001783:Blood Flow Velocity; D016022:Case-Control Studies; D015444:Exercise; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000503:physiopathology*; D007866:Leg; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply*; D055420:Perfusion Imaging / Q000379:methods*; D058729:Peripheral Arterial Disease / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012372:ROC Curve; D012039:Regional Blood Flow; D015203:Reproducibility of Results; D013113:Spin Labels
chemical_list: D013113:Spin Labels