Effect of gadolinium concentration on renal signal intensity: An in vitro study with a saline bag model.
OBJECTIVE
To compare the effects of gadolinium concentration on intermediate-weighted fast inversion-recovery and T2-weighted fast spin-echo magnetic resonance (MR) images by using a saline bag model of the kidney.


METHODS
Normal-saline bags containing gadopentetate dimeglumine in concentrations of 0-20 mmol/L were imaged by using a variety of pulse sequences. Signal intensity was measured.


RESULTS
Signal intensity loss at high gadolinium concentrations (negative enhancement) was demonstrated with all MR sequences. Increasing T2 weighting increased the negative enhancement effect and reduced the minimum gadolinium concentration at which negative enhancement was seen. The results of this study match theoretic predictions.


CONCLUSIONS
The negative enhancement of normal renal tissue seen in intermediate-weighted fast inversion-recovery MR imaging is caused by T2 shortening at high gadolinium concentrations. Thus, gadolinium-enhanced T2-weighted fast spin-echo imaging also is expected to show negative enhancement and may prove to be a superior sequence for MR imaging of pyelonephritis. Further clinical investigation is warranted.
May
D A
DA
Department of Radiology, Medical College of Virginia of Virginia Commonwealth University, PO Box 980615, Richmond, VA 23298-0615, USA. damay@hsc.vcu.edu
Pennington
D J
DJ
D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage*; D005260:Female; D019786:Gadolinium DTPA / Q000008:administration & dosage*; D006801:Humans; D066298:In Vitro Techniques; D007223:Infant; D007668:Kidney / Q000473:pathology*; D008279:Magnetic Resonance Imaging; D019047:Phantoms, Imaging; D011704:Pyelonephritis / Q000175:diagnosis
D003287:Contrast Media; D019786:Gadolinium DTPA