Contrast-enhanced MR imaging of postoperative scars and VX2 carcinoma in rabbits: comparison of macromolecular contrast agent and gadopentetate dimeglumine.
OBJECTIVE
To compare the magnetic resonance (MR) imaging enhancement patterns of a blood pool contrast agent, SH L 643A, with those of gadopentetate dimeglumine in postoperative scars and VX2 carcinomas in rabbits and to compare these enhancement patterns with microvessel density in pathologic specimens.


METHODS
Eighteen rabbits with experimentally induced postoperative scars (n = 12) or VX2 carcinoma (n = 6) in the thighs underwent sequential MR imaging first with gadopentetate dimeglumine and then, 24 hours later, with SH L 643A. The enhancement ratios (ie, the ratios of postcontrast to precontrast signal intensity) and the microvessel densities of postoperative scars and VX2 carcinomas were assessed. Differences were tested for by using the Mann-Whitney U and Wilcoxon signed rank tests.


RESULTS
In postoperative scars, enhancement ratios were consistently lower with injection of SH L 643A than with injection of gadopentetate dimeglumine for up to 30 minutes (P <.05). In postoperative scars, mean peak enhancement ratios were 1.29 +/- 0.15 (SD) with injection of SH L 643A and 1.61 +/- 0.31 with injection of gadopentetate dimeglumine (P <.01). In VX2 carcinomas, the enhancement ratios were not significantly different with injection of SH L 643A than with injection of gadopentetate dimeglumine at all time points. The mean difference between the enhancement ratios of the VX2 carcinomas and postoperative scars was 0.64 +/- 0.10 (range, 0.50-0.77) with SH L 643A and 0.36 +/- 0.16 (range, 0.17-0.66) with gadopentetate dimeglumine (P <.01). The mean microvessel density (in terms of vessels per field of view) was 10.7 +/- 5.5 for postoperative scars and 30.0 +/- 7.7 for VX2 carcinoma (P <.001).


CONCLUSIONS
The difference between the enhancement ratios of postoperative scars and VX2 carcinomas with SH L 643A was greater than that with gadopentetate dimeglumine. Enhancement ratios at SH L 643A-enhanced MR imaging corresponded well with microvessel density in postoperative scars and VX2 carcinomas.
Lee
Joon Woo
JW
Department of Radiology and Clinical Research Institute, Seoul National University Hospital, 28 Yongon-dong, Chongno-gu, Seoul 110-744, Korea.
Moon
Woo Kyung
WK
Weinmann
Hanns-Joachim
HJ
Kim
Soo Jeoung
SJ
Kim
Jong Hyo
JH
Park
Seong Ho
SH
Kim
Tae Jung
TJ
Yoon
Chang Jin
CJ
Kim
Young Hoon
YH
Cho
Eun Yoon
EY
Ha
Sung Whan
SW
Kang
Wee-Saing
WS
Chang
Kee Hyun
KH
D000818:Animals; D002921:Cicatrix / Q000175:diagnosis* / Q000209:etiology; D003287:Contrast Media; D003937:Diagnosis, Differential; D005682:Gadolinium; D019786:Gadolinium DTPA; D008114:Liver Neoplasms, Experimental / Q000175:diagnosis* / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008970:Molecular Weight; D009368:Neoplasm Transplantation; D011817:Rabbits; D013848:Thigh
D003287:Contrast Media; C402765:gadomer 17; D005682:Gadolinium; D019786:Gadolinium DTPA