title: High temporal resolution dynamic MRI and arterial input function for assessment of GFR in pediatric subjects.
abstract: OBJECTIVE
  To introduce a respiratory-gated high-spatiotemporal-resolution dynamic-contrast-enhanced MRI technique and a high-temporal-resolution aortic input function (HTR-AIF) estimation method for glomerular filtration rate (GFR) assessment in children.
  
  
  METHODS
  A high-spatiotemporal-resolution DCE-MRI method with view-shared reconstruction was modified to incorporate respiratory gating, and an AIF estimation method that uses a fraction of the k-space data from each respiratory period was developed (HTR-AIF). The method was validated using realistic digital phantom simulations and demonstrated on clinical subjects. The GFR estimates using HTR-AIF were compared with estimates obtained by using an AIF derived directly from the view-shared images.
  
  
  RESULTS
  Digital phantom simulations showed that using the HTR-AIF technique gives more accurate AIF estimates (RMSE = 0.0932) compared with the existing estimation method (RMSE = 0.2059) that used view-sharing (VS). For simulated GFR > 27 mL/min, GFR estimation error was between 32% and 17% using view-shared AIF, whereas estimation error was less than 10% using HTR-AIF. In all clinical subjects, the HTR-AIF method resulted in higher GFR estimations than the view-shared method.
  
  
  CONCLUSIONS
  The HTR-AIF method improves the accuracy of both the AIF and GFR estimates derived from the respiratory-gated acquisitions, and makes GFR estimation feasible in free-breathing pediatric subjects.
authors.affiliation: Department of Radiology, Stanford University, California, USA.|Department of Electrical Engineering, Stanford University, California, USA.
authors.forename: Umit
authors.initials: U
authors.lastname: Yoruk
authors.affiliation: Department of Radiology, Stanford University, California, USA.
authors.forename: Manojkumar
authors.initials: M
authors.lastname: Saranathan
authors.affiliation: Department of Radiology, Stanford University, California, USA.
authors.forename: Andreas M
authors.initials: AM
authors.lastname: Loening
authors.affiliation: Department of Radiology, Stanford University, California, USA.
authors.forename: Brian A
authors.initials: BA
authors.lastname: Hargreaves
authors.affiliation: Department of Radiology, Stanford University, California, USA.
authors.forename: Shreyas S
authors.initials: SS
authors.lastname: Vasanawala
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003198:Computer Simulation; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D007668:Kidney / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D019047:Phantoms, Imaging; D014567:Urography
keywords: arterial input function estimation; dynamic contrast enhancement; glomerular filtration rate estimation; high spatiotemporal resolution dynamic imaging; urography