title: Hemodynamic response magnetic resonance imaging: application for renal hemodynamic characterization.
abstract: BACKGROUND
  The clinical use of iodinated radiocontrast agents or gadolinium for renal perfusion imaging is limited in the presence of renal dysfunction. We have previously demonstrated the feasibility of hemodynamic response imaging (HRI), a functional magnetic resonance imaging (MRI) method combined with hypercapnia and hypercapnic-hyperoxia, for monitoring changes in liver perfusion and hemodynamics. The aim of the present study was to evaluate the utility of HRI for monitoring changes in renal perfusion and hemodynamics.
  
  
  METHODS
  Renal HRI maps were acquired during graded hypercapnia (95% air + 5% CO2) and hypercapnic-hyperoxia (95% O2 + 5% CO2) in control mice. The utility of HRI for monitoring changes in renal perfusion and oxygenation was evaluated using pharmacological inhibition of nitric oxide synthase and cycloxygenase as well as in rhabdomyolysis-induced acute kidney injury (AKI) in mice. HRI results were further interpreted using Doppler ultrasound (US).
  
  
  RESULTS
  Renal HRI maps revealed pronounced signal-intensity changes in response to both hypercapnia and hypercapnic-hyperoxia, reflecting intense vascular reactivity. These changes were significantly attenuated following the pharmacological intervention and during AKI, corresponding with hampered perfusion dynamics, as confirmed by Doppler US.
  
  
  CONCLUSIONS
  The applicability of the non-invasive HRI method suggests its potential use for the evaluation of renal perfusion and vascular reactivity, excluding the need for contrast-agent administration.
authors.affiliation: The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Jerusalem, Israel.
authors.forename: Zohar
authors.initials: Z
authors.lastname: Milman
authors.forename: Samuel N
authors.initials: SN
authors.lastname: Heyman
authors.forename: Nathalie
authors.initials: N
authors.lastname: Corchia
authors.forename: Yifat
authors.initials: Y
authors.lastname: Edrei
authors.forename: Jonathan H
authors.initials: JH
authors.lastname: Axelrod
authors.forename: Chrisitian
authors.initials: C
authors.lastname: Rosenberger
authors.forename: Galia
authors.initials: G
authors.lastname: Tsarfati
authors.forename: Rinat
authors.initials: R
authors.lastname: Abramovitch
mesh_terms: D058186:Acute Kidney Injury / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D000818:Animals; D003287:Contrast Media; D004195:Disease Models, Animal; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006439:Hemodynamics; D006935:Hypercapnia / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D051379:Mice; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors / Q000378:metabolism; D010100:Oxygen / Q000378:metabolism; D011451:Prostaglandin-Endoperoxide Synthases / Q000737:chemistry / Q000378:metabolism; D012206:Rhabdomyolysis / Q000150:complications*; D018608:Ultrasonography, Doppler
chemical_list: D003287:Contrast Media; D004791:Enzyme Inhibitors; D019001:Nitric Oxide Synthase; D011451:Prostaglandin-Endoperoxide Synthases; D010100:Oxygen
keywords: MRI; acute kidney injury; hypoxia; kidney imaging; renal blood flow