[Ultrasonographic characterization of an experimental model of liver metastases from colon carcinoma in rats].
OBJECTIVE
To determine the ultrasonographic characteristics of liver metastases induced in a rat model; to evaluate the usefulness of ultrasonography in the noninvasive evaluation of tumor infiltration.


METHODS
We seeded the livers of 46 WAG/RijCrl rats with CC-531 syngeneic colorectal carcinoma cells by intrasplenic inoculation. At 21, 28, 35, 42, 70 days after tumor seeding, we performed a series of ultrasonographic examinations to evaluate tumor induction in different groups of animals: 37 rats were studied with a 10 MHz linear probe and 9 were studied with a 6-18 MHz multifrequency probe. The following signs were considered indicative of tumor development: intrahepatic nodules, sinuate liver borders, lobe enlargement, and extrahepatic masses. Ultrasonographic findings were verified at autopsy. We determined the number of implants, size (less than 3mm, between 3 and 7 mm, or greater than 7 mm), and lobe location for each technique.


RESULTS
Compared to the autopsy results, ultrasonography detected 64% of the animals with disease. All the extrahepatic masses were correctly diagnosed. Metastases were identified in 90% of the rats with lesions greater than 7 mm, in 75% of those with implants between 3 and 7 mm, and in 25% of those with lesions less than 3mm. In the group in which we used the 6-18 MHz probe, we detected 50% of the lesions less than 3mm.


CONCLUSIONS
Ultrasonography was useful for monitoring the experimental model and enabled the noninvasive oncologic evaluation of the rat liver with reasonable sensitivity.
Echevarria Uraga
J J
JJ
Servicio de Radiodiagnóstico, Hospital de Galdakao-Usánsolo, Galdakao, Vizcaya, España. FIZER@telefonica.net
García-Alonso Montoya
I
I
Díaz Sanz
I
I
Herrero de la Parte
B
B
Miguélez Vidales
J L
JL
Zabalza Estévez
I
I
Fernández-Ruanova
B
B
D000818:Animals; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000556:secondary*; D003110:Colonic Neoplasms / Q000473:pathology*; D004195:Disease Models, Animal; D005260:Female; D008113:Liver Neoplasms / Q000000981:diagnostic imaging* / Q000556:secondary*; D008297:Male; D051381:Rats; D014463:Ultrasonography