Necrotic areas in VX2 carcinoma of rabbits. Correlation of magnetic resonance imaging and pathologic appearance.

RATIONALE AND OBJECTIVES

To assess the potential of magnetic resonance imaging (MRI) for evaluating the evolution of tumor necrosis, the authors evaluated 28 VX2 carcinomas inoculated in the thigh muscles of rabbits.

METHODS

MRI of VX2 carcinomas at 2.0 T was done with spin-echo technique 1 week (14 tumors) and 3 weeks (14 tumors) after the inoculation of tumor cells. T1- and T2-weighted images were obtained with 500/30 and 2,500/80 sequences; the authors also performed enhanced T1-weighted images with contrast medium. MRI and histopathologic findings were compared.

RESULTS

Enhanced T1-weighted images with gadolinium-DTPA (Gd-DTPA) (dimeglumine gadopentetate) could depict necrosis in almost all tumors (27/28) and were the most sensitive technique followed by T2- and T1-weighted images. T2-weighted images best permitted the evaluation of the characteristics of necrotic areas in VX2 carcinomas, followed by T1-weighted images with contrast enhancement, and unenhanced T1-weighted images. On T2-weighted images, low-intensity areas of necrotic areas correspond to areas of early necrosis, isointense areas corresponded to areas of intermediate necrosis, and high-intensity areas corresponded to the late phase of necrosis.

CONCLUSIONS

MRI is useful in depicting necrosis and characterizing different phases of necrosis in VX2 carcinomas.