title: Early dynamic magnetic resonance imaging of liver metastases with 0.3 and 0.6 mmol/kg gadoteridol injection.
abstract: OBJECTIVE
  The potential for improvement in liver-lesion conspicuity on early dynamic scans after bolus intravenous gadolinium (Gd) chelate administration was evaluated using gadoteridol (Gd-HP-DO3A; Prohance) at doses of 0.3 and 0.6 mmol/kg.
  
  
  METHODS
  Five New Zealand white rabbits with focal VX-2 adenocarcinoma liver metastases were studied on a 1.5-tesla Siemens Vision scanner. Each rabbit was imaged twice (on two separate days), after injections of 0.3 mmol/kg and 0.6 mmol/ kg Gd-HP-DO3A. The contrast dose (0.3 or 0.6 mmol/kg) was given as a single intravenous injection. The order of injection for the two doses was randomized, with the two studies (in any one rabbit) separated by 24 hours to allow for clearance. Contrast was administered using an autoinjector at a rate of 1.5 mL/second. Turbo-fast low-angle shot scans were obtained before and at 6, 12, 19, 25, 31, 60, 120, 180, 240, 300, and 600 seconds after contrast injection. The lesions were confirmed, after killing the rabbit, by gross and microscopic examination.
  
  
  RESULTS
  The enhancement of normal liver parenchyma, assessed by (SIt-SIo)/SIo.100, (SI = signal intensity) peaked at 32% +/- 4% 19 seconds after injection of 0.3 mmol/kg and at 38% +/- 5% 31 seconds after injection of 0.6 mmol/kg. The difference in maximum parenchymal enhancement achieved, comparing the 0.3 and 0.6 mmol/kg doses, was statistically significant (P < 0.03). Lesion conspicuity, specifically (SIliver-SIlesion/noise), increased from 4.5 +/- 2.3 precontrast to a maximum of 6.8 +/- 1.2 at 19 seconds postcontrast using a dose of 0.3 mmol/kg, with the difference statistically significant (P < 0.03). The increase with a dose of 0.6 mmol/kg was from 4.2 +/- 0.7 to 6.5 +/- 1.9 with this difference also statistically significant (P < 0.02). There was no statistically significant difference in lesion conspicuity between the doses of 0.3 and 0.6 mmol/kg.
  
  
  CONCLUSIONS
  Conspicuity of liver metastases can be improved substantially with dynamic magnetic resonance imaging and rapid intravenous bolus contrast injection with a dose of 0.3 mmol/kg. No further improvement is noted at a dose of 0.6 mmol/kg, despite greater positive contrast enhancement of normal liver parenchyma.
authors.affiliation: Magnetic Resonance Imaging and Spectroscopy Center, University of Kentucky, Lexington.
authors.forename: V M
authors.initials: VM
authors.lastname: Runge
authors.forename: J W
authors.initials: JW
authors.lastname: Wells
authors.forename: N M
authors.initials: NM
authors.lastname: Williams
mesh_terms: D000230:Adenocarcinoma / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary*; D000818:Animals; D003287:Contrast Media / Q000008:administration & dosage*; D005682:Gadolinium / Q000008:administration & dosage; D006571:Heterocyclic Compounds / Q000008:administration & dosage; D007089:Image Enhancement / Q000379:methods; D007275:Injections, Intravenous; D008099:Liver / Q000473:pathology; D008113:Liver Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000556:secondary*; D008279:Magnetic Resonance Imaging / Q000379:methods; D009942:Organometallic Compounds / Q000008:administration & dosage; D011817:Rabbits; D011897:Random Allocation
chemical_list: D003287:Contrast Media; D006571:Heterocyclic Compounds; D009942:Organometallic Compounds; C062402:gadoteridol; D005682:Gadolinium