title: A noninvasive method for monitoring renal status at bedside.
abstract: OBJECTIVE
  The authors demonstrate the feasibility of monitoring renal status continuously and noninvasively at a patient's bedside, avoiding both radioactivity and blood and urine samples.
  
  
  METHODS
  Gadolinium-153-labeled ProHance and a glomerular filtration rate (GFR) standard technetium-99m-DTPA were coadministered to anesthetized normal and nephrectomized rats with their tails hanging in a PC 20 spin analyzer. Blood samples and T1 measurements were collected and analyzed.
  
  
  RESULTS
  Log time plots of 153Gd, 99mTc (from blood samples) and T1 of the rat tails were all linear and parallel. Halftimes were 32 +/- 2, 32 +/- 6, and 32 +/- 6 minutes for the decay of the T1, 153Gd and 99mTc, respectively. The halftime of the nephrectomized animal was 2000 +/- 4000 minutes.
  
  
  CONCLUSIONS
  T1 of an appendage remote from the kidneys reflects the concentration of gadolinium in the blood, which is in rapid equilibrium with tissue interstitial space gadolinium. The decay in T1 of the appendage reflects glomerular filtration. Thus, it is feasible to detect changes in renal status at a patient's bedside by monitoring T1 of a finger or wrist using a small, inexpensive magnet.
authors.affiliation: Bracco Research USA Inc., Princeton, New Jersey, USA.
authors.forename: M F
authors.initials: MF
authors.lastname: Tweedle
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.forename: M
authors.initials: M
authors.lastname: Fernandez
authors.forename: P
authors.initials: P
authors.lastname: Wedeking
authors.forename: A D
authors.initials: AD
authors.lastname: Nunn
authors.forename: H W
authors.initials: HW
authors.lastname: Strauss
mesh_terms: D000818:Animals; D003287:Contrast Media; D005240:Feasibility Studies; D005682:Gadolinium; D005919:Glomerular Filtration Rate; D006207:Half-Life; D006571:Heterocyclic Compounds / Q000493:pharmacokinetics; D007668:Kidney / Q000502:physiology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D009942:Organometallic Compounds / Q000493:pharmacokinetics; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D012146:Rest / Q000502:physiology*; D016284:Technetium Tc 99m Pentetate / Q000493:pharmacokinetics
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; D019275:Radiopharmaceuticals; C062402:gadoteridol; D005682:Gadolinium; D016284:Technetium Tc 99m Pentetate