title: Gadolinium-DTPA-dextran: a macromolecular MR blood pool contrast agent.
abstract: OBJECTIVE
  Magnetic resonance (MR) imaging blood pool agents offer numerous advantages for vascular and tumor imaging. The purpose of this study was to test gadolinium-diethylenetriaminepentaacetate-dextran ([Gd]DTPA-dextran) as a new water soluble macromolecular blood pool agent for MR imaging.
  
  
  METHODS
  [Gd]DTPA-dextran (187 gadolinium atoms per dextran, molecular weight 165 kD, diameter 17.6 nm) was synthesized. Fifteen anesthetized New Zealand White rabbits with thigh VX2 tumors were scanned in a knee coil at 1.5T. Coronal 3D MR angiographic sequences were obtained before and at several time points up to 72 hours after the intravenous bolus injection of [Gd]DTPA-dextran providing gadolinium at either 0.05 (n = 4) or 0.1 mmol/kg (n = 8) or [Gd]DTPA-bismethylamide (BMA) providing gadolinium at 0.1 mmol/kg (n = 3). Time enhancement curves for aorta, cava, and tumor rim were compared by univariate General Linear Model.
  
  
  RESULTS
  Contrast enhancement of cava and aorta relative to a water phantom were significantly greater at all time points after either dose of [Gd]DTPA-dextran than after [Gd]DTPA-BMA (P < 0.01). Tumor rim enhancement was less intense for either dose of [Gd]DTPA-dextran at peak than for [Gd]DTPA-BMA (P < 0.05). Tumor rim enhancement with both doses of [Gd]DTPA-dextran became equivalent to that of [Gd]DTPA-BMA at one hour and was greater at 24 hours (P < 0.05).
  
  
  CONCLUSIONS
  [Gd]DTPA-dextran is a new macromolecular MR contrast agent that can be synthesized to carry a high density of gadolinium atoms without intra-molecular cross-linking. It provides significantly greater vascular residence time than a conventional gadolinium chelate and shows promise for MR blood pool imaging.
authors.affiliation: Department of Radiology, University of California, San Diego, 200 West Arbor Drive, San Diego, CA, USA.
authors.forename: Claude B
authors.initials: CB
authors.lastname: Sirlin
authors.forename: David R
authors.initials: DR
authors.lastname: Vera
authors.forename: Jacqueline A
authors.initials: JA
authors.lastname: Corbeil
authors.forename: Marlon B
authors.initials: MB
authors.lastname: Caballero
authors.forename: Richard B
authors.initials: RB
authors.lastname: Buxton
authors.forename: Robert F
authors.initials: RF
authors.lastname: Mattrey
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000138:chemical synthesis / Q000737:chemistry; D003911:Dextrans / Q000138:chemical synthesis / Q000737:chemistry; D019786:Gadolinium DTPA / Q000138:chemical synthesis / Q000737:chemistry; D016014:Linear Models; D046911:Macromolecular Substances / Q000138:chemical synthesis / Q000737:chemistry; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D011817:Rabbits
chemical_list: D003287:Contrast Media; D003911:Dextrans; D046911:Macromolecular Substances; D019786:Gadolinium DTPA