title: Gadolinium-enhanced T1-weighted renal and abdominal MR imaging: quantitative discrepancy between clinical and in vitro findings.
abstract: OBJECTIVE
  This study was conducted to compare the magnetic resonance (MR) contrast medium enhancement of abdominal organs in vivo with the signal intensity (SI) values of known in vitro gadolinium solutions.
  
  
  METHODS
  A phantom was imaged with the MR contrast medium gadodiamide (Omniscan; Nycomed, Princeton, NJ) of solutions at full-strength (0.5 mmol/mL), one-third, 1/10, and 1/100 concentrations. A fat-suppressed fast spoiled gradient-echo pulse sequence with flip angles ranging from 10 degrees to 170 degrees (at 20 degrees increments) was performed with a 1.5-T magnet. In 12 subjects, the SIs of abdominal organs were determined with identical imaging parameters, before and after administration of gadodiamide injection at 0.1 mmol/kg.
  
  
  RESULTS
  As anticipated, the plot of SI in relation to gadodiamide concentration is nonlinear, with a decrease in SI due to T2 effects at concentrations above 0.05 mmol/mL. The kidney showed the highest SI after gadodiamide enhancement (125.2 +/- 11.6 [standard error] at 2.5 minutes), followed by the liver (76.5 +/- 11.5 at 1 minute) and spleen (57.26 +/- 9.35 at 30 seconds). The SI of the renal medulla (114.2 +/- 9.8 at 4.5 minutes) was approximately one-third that in phantom observations.
  
  
  CONCLUSIONS
  The authors observed a marked discrepancy between empirical contrast medium performance in abdominal organs and SI values for comparable gadodiamide concentrations in vitro. One possible reason is the intracellular compartmentalization of water molecules in vivo. These results suggest a need for a better understanding of MR contrast medium performance in vivo.
authors.affiliation: Department of Radiology, University of California/Davis Medical Center, Research Imaging Center, Sacramento, CA 95817, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Katzberg
authors.forename: Marija
authors.initials: M
authors.lastname: Ivanovic
authors.forename: Michael H
authors.initials: MH
authors.lastname: Buonocore
authors.forename: Claire
authors.initials: C
authors.lastname: Pellot-Barakat
authors.forename: John M
authors.initials: JM
authors.lastname: Brock
authors.forename: John M
authors.initials: JM
authors.lastname: Ryan
authors.forename: Kevin
authors.initials: K
authors.lastname: Whang
mesh_terms: D000005:Abdomen / Q000033:anatomy & histology*; D000328:Adult; D000368:Aged; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D006869:Hydronephrosis / Q000473:pathology; D007668:Kidney / Q000033:anatomy & histology* / Q000473:pathology; D007679:Kidney Medulla / Q000033:anatomy & histology / Q000473:pathology; D008099:Liver / Q000033:anatomy & histology; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019047:Phantoms, Imaging; D016658:Psoas Muscles / Q000033:anatomy & histology; D013154:Spleen / Q000033:anatomy & histology
chemical_list: D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA