title: Combined measurement of perfusion, venous oxygen saturation, and skeletal muscle T2* during reactive hyperemia in the leg.
abstract: BACKGROUND
  The function of the peripheral microvascular may be interrogated by measuring perfusion, tissue oxygen concentration, or venous oxygen saturation (SvO2) recovery dynamics following induced ischemia. The purpose of this work is to develop and evaluate a magnetic resonance (MR) technique for simultaneous measurement of perfusion, SvO2, and skeletal muscle T2*.
  
  
  METHODS
  Perfusion, Intravascular Venous Oxygen saturation, and T2* (PIVOT) is comprised of interleaved pulsed arterial spin labeling (PASL) and multi-echo gradient-recalled echo (GRE) sequences. During the PASL post-labeling delay, images are acquired with a multi-echo GRE to quantify SvO2 and T2* at a downstream slice location. Thus time-courses of perfusion, SvO2, and T2* are quantified simultaneously within a single scan. The new sequence was compared to separately measured PASL or multi-echo GRE data during reactive hyperemia in five young healthy subjects. To explore the impairment present in peripheral artery disease patients, five patients were evaluated with PIVOT.
  
  
  RESULTS
  Comparison of PIVOT-derived data to the standard techniques shows that there was no significant bias in any of the time-course-derived metrics. Preliminary data show that PAD patients exhibited alterations in perfusion, SvO2, and T2* time-courses compared to young healthy subjects.
  
  
  CONCLUSIONS
  Simultaneous quantification of perfusion, SvO2, and T2* is possible with PIVOT. Kinetics of perfusion, SvO2, and T2* during reactive hyperemia may help to provide insight into the function of the peripheral microvasculature in patients with PAD.
authors: Department of Radiology, Laboratory of Structural NMR Imaging, University of Pennsylvania Medical Center, 3400 Spruce Street, Philadelphia, PA 19104, USA. wehrli@mail.med.upenn.edu.
authors: Erin K
authors: EK
authors: Englund
authors: Michael C
authors: MC
authors: Langham
authors: Cheng
authors: C
authors: Li
authors: Zachary B
authors: ZB
authors: Rodgers
authors: Thomas F
authors: TF
authors: Floyd
authors: Emile R
authors: ER
authors: Mohler
authors: Felix W
authors: FW
authors: Wehrli
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000097:blood / Q000503:physiopathology; D035002:Lower Extremity; D008279:Magnetic Resonance Imaging; D008297:Male; D008833:Microcirculation; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000098:blood supply*; D010100:Oxygen / Q000097:blood*; D055420:Perfusion Imaging / Q000379:methods*; D058729:Peripheral Arterial Disease / Q000097:blood / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D013997:Time Factors
chemical_list: D015415:Biomarkers; D010100:Oxygen
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