In vivo magnetic resonance volumetric and spectroscopic analysis of mouse prostate cancer models. Fricke ST, Rodriguez O, Vanmeter J, Dettin LE, Casimiro M, Chien CD, Newell T, Johnson K, Ileva L, Ojeifo J, Johnson MD, Albanese C, Lombardi Cancer Center, Department of Neuroscience, Georgetown University Medical Center, Washington, DC

Background: Mouse prostate cancer modeling presents unique obstacles to the study of spontaneous tumor initiation and progression due to the anatomical location of the tissue. Results: High resolution [130 microm(x) × 130 microm(y) × 300 microm(z)], three-dimensional MRI allowed for the visualization, segmentation, and volumetric measurement of the prostate from normal and genetically engineered animals, in vivo. Additionally, MRS performed on the prostate epithelia of probasin-ErbB-2Delta × Pten(+/-) mice identified changes in the relative concentrations of the metabolites choline and citrate, which was not observed in TRAMP mice. Methods: T1-weighted MRI was performed on normal, TRAMP, probasin-ErbB-2/Her2/Neu (probasin-ErbB-2Delta), and probasin-ErbB-2Delta in the context of decreased Pten activity [probasin-ErbB-2Delta × Pten(+/-)] mice. Volume-localized single-voxel proton magnetic resonance spectroscopy (SVS 1H-MRS) was also performed. Conclusions: The data presented supports the use of combined MRI and MRS for the measurement of biochemical and morphometric alterations in mouse models of prostate cancer.