Visualization and quantification of transplanted Dunning prostate tumors in rats using magnetic resonance imaging.

Quantitative magnetic resonance imaging (MRI) has been used for the in vivo size determination of subcutaneously implanted Dunning R3327-H tumors in male Copenhagen-Fisher rats (N = 18). Images have been recorded using a multislice spin-echo sequence SE(1000/36) with a resolution of 0.2 x 0.2 mm2 in the imaging plane and a slice thickness of 2 mm. The reliability in the MRI size determination was of the order of 10%. The MRI results were compared with caliper measurements. Five months after tumor implantation nine rats were castrated. Orchiectomy led to a marked and statistically significant reduction in tumor growth rate as determined by both methods of quantification. Qualitative MRI information regarding the tumor morphology was compared with that for histological specimens.