Dynamic magnetic resonance tomography and proton magnetic resonance spectroscopy of prostate cancers in rats treated by radiotherapy

Rationale and Objectives: To establish an experimental setting for monitoring perfusion and metabolism in orthotopic prostate cancer at 1.5 T using dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) and H-1-MR spectroscopy (MRS). Methods: Dunning rat prostate cancer cells were injected into the prostate by open surgery. Twelve tumor-bearing rats (5 of these irradiated) and 6 healthy controls were followed up using gadolinium-diethylenetriaminepentaacetic acid -enhanced dynamic MRI and H-1-MRS. Amplitude and the exchange rate constant k(ep) were calculated (2-compartment model). From H-1-MR spectra, ratios of choline (Cho) and creatine (tCr) were calculated. All tumors were examined histologically. Results: On DCE MRI parameter maps, tumors showed increased vascularization. k(ep) and microve.ssel density were correlated (r = 0.97). Tumors showed elevated Cho/tCr and an unexpected lipid fraction (2.0-2.2 parts per million). Irradiation slowed tumor growth significantly. Changes of perfusion and metabolism could be detected in all tumors during follow up. Conclusion: DCE MRI and H-1-MRS has potential to characterize orthotopic Dunning prostate cancer in rats, which is a promising model similar to human prostate carcinomas.