Analysis of Signal Intensity Curve on Dynamic Contrast-Enhanced MR Imaging of Postoperative Scars in Rabbits:Comparison of Gadopentetate Dimeglumine and 24-gadolinium-tetraazacy-clododecanetetraacetic acid (DOTA)-dendrimer

ABSTRACT

PURPOSE: To compare the enhancement patterns of 24-gadolinium-tetrazacyclodode-cane tetracetic acid (DOTA)-dendrimer (Gadomer-17) with those of gadopentetate dimeglumine (Magnevist) in postoperative scars in rabbits. MATERIALS AND METHODS: Twelve rabbit thighs with experimentally induced postoperative scars underwent dynamic contrast-enhanced MR imaging with both Gadomer-17 and gadopentetate dimeglumine at a 24-hr interval at one (n = 10), two (n = 8) and three months (n=4) after scar induction. The enhancement and the ratios of lesions at each time point, peak enhancement ratios, and the slope and shape of curves were assessed. RESULTS: At all time points, enhancement ratios were significantly lower after the injection of Gadomer-17 than with gadopentetate dimeglumine (p<0.05). Peak enhancement ratios were significantly lower with Gadomer-17 (1.29+/-0.15) than with gadopentetate dimeglumine (1.61+/-0.31) (p<0.01). The slope values were 2.99%/min+/-2.72 after Gadomer-17 injection and 8.99%/min+/-7.32 after gadopentetate dimeglumine injection (p<0.01). The enhancement ratio curves showed mostly the plateau pattern with Gadomer-17 (90.9%), while for gadopentetate dimeglumine, the curve pattern was either plateau (50%) or washout (50%). Difference in enhancement characteristics between the two contrast agents were most pronounced for one-month scars. CONCLUSION: With Gadomer-17, weaker enhancement and the plateau pattern were found in postoperative scars, whereas stronger enhancement and either washout or the plateau pattern were found with gadopentetate dimeglumine.