Gadolinium-enhanced T1-weighted renal and abdominal MR imaging: quantitative discrepancy between clinical and in vitro findings.
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.
Katzberg
Richard W
RW
Department of Radiology, University of California/Davis Medical Center, Research Imaging Center, Sacramento, CA 95817, USA.
Ivanovic
Marija
M
Buonocore
Michael H
MH
Pellot-Barakat
Claire
C
Brock
John M
JM
Ryan
John M
JM
Whang
Kevin
K
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
D003287:Contrast Media; C064925:gadodiamide; D019786:Gadolinium DTPA