Evolution of VX2 carcinoma in rabbit tibia: magnetic resonance imaging with pathologic correlation.
OBJECTIVE
To evaluate the evolution of a metastatic bone tumor model with MRI-pathology correlation.


METHODS
VX2 carcinoma was implanted into the tibiae of 20 rabbits. The rabbits were divided into four groups of five (Groups I-IV). MRI was repeated at 1-week interval up to the fourth week, including sagittal T1-weighted image (T1WI), T2-weighted image (T2WI), gadolinium-enhanced fat-suppressed T1WI (GdT1WI), and diffusion-weighted image (DWI). Each group was sacrificed after the imaging, then histological examination for the tibiae with an implanted tumor was performed and MRI-pathologic correlation was done.


RESULTS
On MRI-pathology correlation, the corresponding findings were as follows; low SI on T1WI, T2WI-tumor cells, fibrosis (1 week); central low SI on T1WI, T2WI, GdT1WI -tumor cells with fibrosis and necrosis; peripheral high SI on T2WI, DWI, GdT1WI-edema, fibrosis (2 weeks); heterogeneous SI with central low SI on T2WI, DWI-tumor cell nests with extensive necrosis, fibrosis; high SI on T2WI along periosteum-periosteal reaction; high SI around low SI and in bone marrow on T2WI, DWI, GdT1WI-edema, fibrosis; low SI on T1WI in surrounding bone marrow-tumor extension (3-4 weeks).


CONCLUSIONS
The evolution of VX2 carcinoma model was well depicted on MR imaging. Necrosis and extent of tumor were best depicted on enhanced, fat-suppressed T1-weighted images. Heterogeneity of the tumor, peripheral edema, and fibrosis were represented well on T2-weighted images. Diffusion-weighted imaging could have a role in depicting necrosis in the evaluation of bone tumor.
Choi
Jung-Ah
JA
Department of Radiology and Institute of Radiation Medicine, Seoul National University College of Medicine, Seoul, South Korea.
Kang
Eun Young
EY
Kim
Han Kyeom
HK
Song
In Chan
IC
Kim
Young I I
YI
Kang
Heung Sik
HS
D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology* / Q000556:secondary*; D008279:Magnetic Resonance Imaging; D009336:Necrosis; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000473:pathology; D011817:Rabbits; D013977:Tibia / Q000473:pathology*